bread and yeast experiment

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Yeast and the expansion of bread dough

In association with Nuffield Foundation

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Try this class practical to investigate how temperature affects yeast and the expansion of bread dough

Yeast is a microbe used in bread making which feeds on sugar. Enzymes in yeast ferment sugar forming carbon dioxide and ethanol. The carbon dioxide makes the bread rise, while the ethanol evaporates when the bread is baked. In this experiment, students investigate the effect of different temperatures on yeast activity and the expansion of the bread dough.

It is best if each group does the activity at one temperature and then shares the results with other groups.

• Spatula or glass rod
• Beaker, 100 cm 3
• Measuring cylinder, 250 cm 3
• Measuring cylinder, 50 cm 3
• Thermometer, 0–100 °C
• Graph paper
• Access to a balance (1 d.p.)
• Access to water baths set at 20 °C, 30 °C and 37 °C (see note 2 below)
• Plain flour, 25 g
• Yeast suspension, 30 cm 3 (see note 3 below)

Health, safety and technical notes

• Read our standard health and safety guidance.
• If thermostatically controlled water baths are not available then large beakers of water maintained at the three temperatures can be used. The water temperature in each beaker needs to be monitored using a thermometer, and access to a supply of hot water, eg from a kettle, is needed to top up the beaker as the temperature falls. 
• The yeast suspension is made by stirring 7 g of dried yeast with 450 cm 3 of warm water. If fresh yeast is used it should not have been kept too long. Fresh yeast can be kept in the freezer for up to two months.
• Add 25 g of flour to a beaker and then add 1 g of sugar.

Source: Royal Society of Chemistry

Weigh flour and sugar for a simple bread dough

• Take 30 cm 3 of the yeast suspension in a 50 cm 3 measuring cylinder. Add the yeast suspension to the flour and sugar. Stir with a spatula or glass rod until a smooth paste, which can be poured, has been obtained.
• Pour the paste into a 250 cm 3 measuring cylinder. Take great care not to let the paste touch the sides – this is very important.

Make a paste from the flour, sugar and yeast suspension and pour it into a measuring cylinder

• Note the volume of paste in the cylinder. Place the cylinder in one of the water baths. Record the temperature and note the volume of paste every two minutes for about 30 minutes. A results table is useful here.
• Plot a graph to show how the volume of the dough increases with time. Plotting the results from groups, with the water baths at different temperatures, on the same graph will allow comparison of results.

Teaching notes

It is important that the paste does not touch the sides of the measuring cylinder when the students pour it from the beaker – this is easier said than done. One way of achieving this is to use a large plastic funnel which has had the stem cut off to leave a hole large enough for the paste to flow through the funnel. Alternatively, a suitable plastic drinks bottle could be cut to produce a wide mouthed ‘funnel’.

After 35–45 minutes the protein (gluten) breaks and carbon dioxide gas escapes.

Possible extensions for this activity could be to investigate the effect of substrate concentration (sugar), enzyme concentration and/or pH value on enzyme reactions.

Additional information

This is a resource from the  Practical Chemistry project , developed by the Nuffield Foundation and the Royal Society of Chemistry.

Practical Chemistry activities accompany  Practical Physics  and  Practical Biology .

© Nuffield Foundation and the Royal Society of Chemistry

• 11-14 years
• 14-16 years
• Practical experiments
• Biological chemistry

Specification

• 7. Investigate the effect of a number of variables on the rate of chemical reactions including the production of common gases and biochemical reactions.
• 9. Consider chemical reactions in terms of energy, using the terms exothermic, endothermic and activation energy, and use simple energy profile diagrams to illustrate energy changes.
• 2. Develop and use models to describe the nature of matter; demonstrate how they provide a simple way to to account for the conservation of mass, changes of state, physical change, chemical change, mixtures, and their separation.
• Awareness of the contributions of chemistry to society, e.g. provision of pure water, fuels, metals, medicines, detergents, enzymes, dyes, paints, semiconductors, liquid crystals and alternative materials, such as plastics, and synthetic fibres; increasi…
• Enzymes as catalysts produced by living cells (two examples).

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Yeast Science Experiment for Kids

Make homemade bread and bake in a science lesson..

Introduce your child to the amazing power of yeast!

Mix a packet of active yeast with ¼ cup of warm water and a tsp of sugar in a bowl. After 10 minutes, your child will see the mixture foaming--a sign that the microbes are feeding and producing carbon dioxide. Talk about the role those CO2 bubbles play in making dough rise!

What happens when you leave out the sugar? (Hint: organisms like yeast need to eat sweet stuff to multiply.) After you’ve baked your bread, see if your kiddo can spot the connection between the foaming yeast and the air pockets in a slice. (Then butter it, and snack!)

Break Bread

Find a no-knead bread recipe at  Simply-edible.com . Source: Dorothy Munn, educator, Michigan State University Extension youth program

Plus: Easy (and Mess-Free!) Science Experiments 5 Creative Science Experiment Crafts for Kids

Photo Credit: Melanie Acevedo

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Agricultural Literacy Curriculum Matrix

Lesson plan, grade levels, type of companion resource, content area standards, agricultural literacy outcomes, common core, food science: bread dough challenge, grade level.

Students explore the phenomenon of what makes bread dough rise. Using baker's yeast, students will observe alcoholic fermentation and its connection to cellular respiration as they are challenged to act as food scientists and develop the best recipe for quick-rising bread dough.  Grades 9-12

Estimated Time

Two 1-hour sessions

Materials Needed

Engage: 

• Time Lapse - Pizza Dough Rising  video

Activity 1: What makes bread dough rise?

• 3 sandwich-sized Ziploc bags
• 1 tablespoon measuring spoon
• Food Science: Bread Dough Challenge handout , 1 per student
• Food Science: Bread Dough Challenge PowerPoint

Activity 2: Bread dough Challenge

• Food Science: Bread Dough Challenge  handout, 1 per student (continued from Activity 1 )
• Bread Dough Challenge Variables sheet , 1 copy per class printed front to back, cut into quarters
• 1 glass Mason jar or clear glass beaker
• 1 cup flour
• 1 tablespoon sugar
• 1/3 cup warm water
• 1 teaspoon active dry yeast
• 1 teaspoon cooking oil
• 1 plastic spoon for stirring
• 1 paper/plastic bowl for mixing
• Rapid-rise yeast
• Vital wheat gluten
• 1 cup whole wheat flour
• 1 cup gluten-free flour (rice, coconut, oat, etc.)
• Sugar substitute such as Splenda
• Alternative sugar such as honey, brown sugar, or molasses

Essential Files

• (optional) Cellular Respiration Concept Map

alcoholic fermentation: an anaerobic pathway that converts the pyruvate made in glycolysis to ethanol, produces CO2, and regenerates NAD

anaerobic: without the use of oxygen

asexual reproduction: a form of reproduction involving a single parent and producing offspring that are exact genetic duplicates

budding: a form of asexual reproduction where parent cell forms a bubble-like bud that stays attached to the parent cell while it grows and develops; then breaks away to form a new organism

cellular respiration: process by which cells release energy from glucose and convert it to ATP

food science: the study of the physical, biological, and chemical makeup of food and the concepts underlying food processing

gluten: a tough, elastic protein substance in flour, especially from wheat, that holds dough together and makes it sticky

lactic acid fermentation: an anaerbic pathway that converts the pyruvate made in glycolysis to lactic acid, regenerating NAD

Did You Know?

• It takes 9 seconds for a combine to harvest enough wheat to make about 70 loaves of bread. 1
• Yeast are microorganisms. They are single-celled fungi. 2
• Yeast produces carbon dioxide when it consumes sugar. 3
• It takes 20 billion yeast cells to weigh one gram of cake yeast. 4

Background Agricultural Connections

This lesson can be nested into a storyline as an episode exploring the phenomenon of bread dough rising. In this episode, students investigate the question, "What makes bread dough rise?" Phenomena-based lessons include storylines which emerge based upon student questions. Other lesson plans in the National Agricultural Literacy Curriculum Matrix may be used as episodes to investigate student questions needing science-based explanations. For more information about phenomena storylines visit nextgenstorylines.org .

Cellular respiration can be a difficult topic for students to understand because it cannot be directly observed. In this lesson, students who have studied the basics of aerobic cellular respiration will be introduced to alcoholic fermentation and will conduct a simple experiment to determine how yeast gets energy from sugar. Students who aren’t familiar with using yeast in baking may wonder if it’s alive, which is another great opportunity for discussion.

Yeasts are unicellular fungi that reproduce asexually. The species Saccharomyces cerevisiae is used in bread baking and wine and beer brewing. S. cerevisiae is also used as a model organism in many laboratories because it is easy and inexpensive to culture. It is a facultative anaerobe, meaning that it undergoes both aerobic and anaerobic fermentation. In the absence of oxygen, yeast and other organisms undergo alcoholic fermentation, producing CO 2 and ethanol and regenerating the NAD+ needed to continue glycolysis. While this produces less ATP than aerobic respiration, some ATP is still produced.

Yeast cells do more than respire, they go through a form of asexual reproduction called budding. Asexual reproduction involves a single parent and results in offspring that are genetically identical to each other and to the parent. Budding occurs when a parent cell forms a bubble-like bud that stays attached to the parent cell while it grows and develops. Then, it breaks away and forms a new organism.

Students may be interested to learn that yeast is all around us; sourdough bread is made by allowing yeast in the air and in the flour to colonize a mixture of flour and water. The CO 2 produced during yeast metabolism is captured in bread dough, causing it to rise. The protein gluten provides a structure for the bubbles of CO 2 . Kneading is necessary to develop and strengthen the crosslinks between gluten molecules. If dough is not kneaded enough, it won’t be elastic enough to capture the CO 2 bubbles, resulting in a flat loaf. Gluten is not found in some grains, such as oats and rice. Students who try to make a dough with gluten-free flour may find that it won’t rise at all.

In Activity 2 , students are challenged to act as food scientists to develop a recipe for quick-rising bread dough. Agricultural companies, like General Mills, Land O Lakes, and Cargill, challenge food scientists to utilize raw agricultural products as efficiently as possible to develop consumer-demanded food products.  If Activity 2 must be broken up over two class periods, it might be helpful to have students mix together the dry ingredients of their dough (Step 11) on the first day so they are ready to start immediately on day two.

• Ask students, "What is causing this pizza dough to rise?" When students offer "yeast" as an answer, question further. For example, "What is yeast?" or "How does yeast make dough rise?"

Explore and Explain

Activity 1: What makes bread dough rise?

• Introduce yeast by passing around small Ziploc bags of yeast or displaying one at the front of the room. Ask students if they know what it is and what it is used for. If no one knows, explain that it is yeast and that our primary use for it is in cooking.
• Fill 3 quart or sandwich sized ziploc bags with 1 tablespoon of yeast per bag.
• Add 1 tablespoon of sugar to bag two and 3 tablespoons of sugar to bag three. (Bag 1 will serve as the control and will not have any sugar.)
• Place 1/2 cup of warm water in each bag and mix the contents thoroughly with your fingers.
• Push the air out of the bag and seal tightly.
• Place bags in a central area for observation.
• Tip: It will take approximately 20 minutes for the ziploc bags to fully inflate. However, exact time will vary depending on the temperature of your classroom. The next steps may be interchanged as needed for class flow.
• Using PowerPoint slides 2-5, discuss the answers to the four questions contained on the first page of the handout.
• Safety Note: Be sure to open the ziploc bags before they pop.
• Using the second page of the handout, draw on students' prior knowledge and have them answer the questions about how various organisms obtain energy.

Activity 2: Bread Dough Challenge

• Ask students if they can name any food products that are made using yeast and alcoholic fermentation. Examples include bread, beer, and wine.
• Tell students that one of the challenges to making bread (at home or on the industrial scale) is the time that it takes to allow the dough to rise. Food scientists use engineering, biology, and chemistry to evaluate and improve food products from the farm to the kitchen.
• Tell students that they are on a team of food scientists at a bread company. They will be working together to discover the best recipe and preparation procedures to produce quick rising bread. To test as many variables as possible, the class will be divided into small groups.
• Divide your class into 8-12 groups and assign each group one  Bread Dough Challenge Variable .  You can use any of the variables provided, or have students think of their own. Preselect the optional variables based on your class size and/or lab supplies available.
• Tip: As students determine their variables and how they will manipulate them for the experiment, allow them to pursue the wrong direction to provide an authentic learning experience and the opportunity to explain the outcome using science. For example, knowing that yeast needs sugar to grow, a student may greatly increase the amount of sugar in the recipe. If the yeast is not increased, this sample will not rise faster. It may not rise as much or even at all depending on the ratio. Refer to information about the  molar concentration of sucrose for an explanation. 
• Provide lab supplies, answer student questions, and tell students where to take their dough once it is mixed. Have students fold their variable card in half to make a tent label to identify their dough.
• Using a dry erase marker, have each group place a starting line on their jar at the level of the dough. 
• Allow at least 30 minutes for the bread dough to rise. Instruct students to place a second line at the level of the dough after 30 minutes. 
• Place all dough jars for students to observe. After observation time is over, allow students time to complete the last page of their handout which will contain their final recommendation to the bread company.

Have students complete the attached Cellular Respiration concept map . Print the blank diagram (page 1) or the diagram with hints (page 2). Students can use a textbook or internet search to complete the diagram. The word bank on page 3 can also be projected or printed for reference. The teacher key is found on page 4.

Discover other foods that are created using the process of fermentation. Examples include cheese, sauerkraut, pickles, kimchi, and root beer. Divide the class into small groups. Assign each group to research a specific fermented food and create a "how to" brochure outlining how the food is made.

Show students where wheat is grown in the United States. Use the  wheat map  from the Interactive Map Project . Find your state and determine how much wheat your state grows annually.

Have students create a graph of their data and the control from Activity 2. Students can create the graph by hand or by using graphing software such as Google Spreadsheets or Microsoft Excel. Have each group display their graph to the class. 

After conducting these activities, review and summarize the following key concepts:

• Food Science is a career area in agriculture. Many agricultural companies employ food scientists to develop raw agricultural commodities into marketable food products.
• Science is used to produce and process our food. The process of alcoholic fermentation is used in making bread dough.
• Bread dough rises as yeast processes sugar and produces carbon dioxide, the gas that makes the dough rise.
• Gluten is the protein found in wheat flour.
• https://mobile-cuisine.com/did-you-know/bread-fun-facts/
• https://wiki.kidzsearch.com/wiki/Yeast
• http://www.ilove2bake.co.za/learn-more-about-yeast-6-8-interesting-facts/
• https://redstaryeast.com/science-yeast/what-is-yeast/

Acknowledgements

This lesson was originally written by Ann Butkowski for Minnesota Agriculture in the Classroom. It was updated and revised in 2019 by the National Center for Agricultural Literacy.

Phenomenon chart adapted from work by Susan German. German, S. (2017, December). Creating conceptual storylines.  Science Scope , 41(4), 26-28. German, S. (2018, January). The steps of a conceptual storyline.  Science Scope , 41(5), 32-34.

Recommended Companion Resources

• Amazing BREAD Processing- How It's Made Inside a Factory
• Dirt to Dinner
• Modern Marvels: World's Largest Combine

Ann Butkowski and Andrea Gardner

Organization

Minnesota Agriculture in the Classroom and National Center for Agricultural Literacy

Culture, Society, Economy & Geography

• Describe essential agricultural careers related to production, consumption, and regulation (T5.9-12.d)

Science, Technology, Engineering & Math

• Predict the types of careers and skills agricultural scientists will need in the future to support agricultural production and meet the basic needs of a growing population (T4.9-12.f)

Education Content Standards

Career & technical education (career).

AFNR (Grades 9-12) Food Products and Processing Systems Career Pathway

• FPP.02.01    Apply principles of nutrition and biology to develop food products that provide a safe, wholesome and nutritious food supply for local and global food systems.
• FPP.02.02    Apply principles of microbiology and chemistry to develop food products to provide a safe, wholesome and nutritious food supply for local and global food systems.

AFNR (Grades 9-12) Career Ready Practices

• CRP.10.1    Identify career opportunities within a career cluster that match personal interests, talents, goals and preferences.

Science (SCIENCE)

HS-LS2 Ecosystems: Interactions, Energy, and Dynamics

• HS-LS2-3    Construct and revise an explanation based on evidence for the cycling of matter and flow of energy in aerobic and anaerobic conditions.
• HS-LS2-5    Develop a model to illustrate the role of photosynthesis and cellular respiration in the cycling of carbon among the biosphere, atmosphere, hydrosphere, and geosphere.

Common Core Connections

Anchor standards: writing.

CCSS.ELA-LITERACY.CCRA.W.7 Conduct short as well as more sustained research projects based on focused questions, demonstrating understanding of the subject under investigation.

Practice Standards: Mathematics

CCSS.MATH.PRACTICE.MP1 Make sense of problems and persevere in solving them. Students start by explaining to themselves the meaning of a problem and looking for entry points to its solution. They analyze givens, constraints, relationships, and goals. They make conjectures about the form and meaning of the solution and plan a solution pathway rather than simply jumping into a solution attempt. They consider analogous problems, and try special cases and simpler forms of the original problem in order to gain insight into its solution. They monitor and evaluate their progress and change course if necessary. Students check their answers to problems using a different method, and they continually ask themselves, “Does this make sense?” They can understand the approaches of others to solving complex problems and identify correspondences between different approaches.

CCSS.MATH.PRACTICE.MP5 Use appropriate tools strategically. Students consider the available tools when solving a mathematical problem. These tools might include pencil and paper, concrete models, a ruler, a protractor, a calculator, a spreadsheet, a computer algebra system, a statistical package, or dynamic geometry software. Students at various grade levels are able to identify relevant external mathematical resources, such as digital content located on a website, and use them to pose or solve problems. They are able to use technological tools to explore and deepen their understandings of concepts.

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Bread Science 101

From Chinese baozi to Armenian lavash, bread comes in thousands of forms. What do they have in common? On the most basic level, they all involve cooking a mixture of milled grains and water.

Imagine a continuum of breads, ranging from the thinnest flatbreads to the fluffiest brioche. Some are amazingly simple: Matzoh, for example, is nothing more than flour and water, baked until crisp. Raised breads, on the other hand, involve the complex interactions between flour and the leaveners that give them their porous, tender quality.

Leaveners come in two main forms: baking powder or soda and yeast.

Baking Powder and Baking Soda

Yeast, on the other hand, is a live, single-celled fungus. There are about 160 species of yeast, and many of them live all around us. However, most people are familiar with yeast in its mass-produced form: the beige granules that come in little paper packets. This organism lies dormant until it comes into contact with warm water. Once reactivated, yeast begins feeding on the sugars in flour, and releases the carbon dioxide that makes bread rise (although at a much slower rate than baking powder or soda). Yeast also adds many of the distinctive flavors and aromas we associate with bread. For more on yeast, check out our fun yeast activity .

But leavening agents would just be bubbling brews without something to contain them. Here is where flour comes in. There are lots of different types of flour used in bread, but the most commonly used in raised bread is wheat flour. This is because wheat flour contains two proteins, glutenin and gliadin , which, when combined with water, form gluten. As you knead the dough, the gluten becomes more and more stretchy. This gum-like substance fills with thousands of gas bubbles as the yeast goes to work during rising.

Starch, a carbohydrate that makes up about 70% of flour by weight, also gets in on the act. When starch granules are attacked by enzymes present in flour, they release the sugars that yeast feeds on. Starch also reinforces gluten and absorbs water during baking, helping the gluten to contain the pockets of gas produced by the yeast.

Sometimes, a baker will let the dough rise several times, allowing the gluten to develop more completely and the yeast to add more of its flavors. When the dough is finally cooked either in an oven, over a fire, or in a steamer, depending on what kind of bread you ’ re baking—the yeast inside it continues feeding, and the pockets of gas in the dough continue to expand. As the temperature of the cooking dough rises, the yeast eventually dies, the gluten hardens, and the dough solidifies. Et voilà! Bread!

For more about bread science, check out these links !

More from the Science of Cooking

Yeast Experiments and Bread in a Bag

Introduction: Yeast Experiments and Bread in a Bag

Overview: Making “bread in a bag” is a popular classroom activity (see resources section). In addition to the fun and satisfaction inherent in making something you can eat, bead baking is an excellent introduction to food science, measurement, and following multistep instructions. This activity takes it a step further, asking students to investigate yeast and what yeast needs to grow. These activities can be part of an introduction to cells, and a bridge between discussing single-celled organisms like yeast and the more complex systems of our bodies.

Notes : The activity can be done as a kit for remote learning. You should check with your school about policies on cooking and eating recipes in class or at home. You may need to purchase ingredients in individually sealed packages, modify recipes based on food allergies, or do the yeast experiments as a class and suggest the bread recipe as an option for families to use at home at their discretion.

(Amounts will vary depending on how many experiments you do. A suggested per-student amount is given, assuming two rounds of 5 experiments. Equivalents are given for a remote learning kit.)

Necessary per student:

Yeast : Per-student: at least 5 teaspoons (Kit: 4-5 packages, each packet is 2.25 teaspoons. Bulk: approximately 160 teaspoons in a pound of active dry yeast.)

Flour : Per-student: at least 4 cups, ideally more. (Kit: 2-pound bag per kit. Bulk: approximately 3 ⅓ cups per pound.)

Sugar : Per-student: 10 teaspoons (Kit: 10 teaspoon packets. Bulk: approximately 108 teaspoons in a pound of sugar.)

Salt : Per-student: 10 teaspoons (Kit: 60 packets, or one salt shaker. A teaspoon of salt equals 12-15 salt packets. You can also reduce the amount of salt in the recipe by half. Bulk: approximately 79 teaspoons in a pound of salt.)

Zip close bags : Per-student: at least 10 (“sandwich size” or one-quart capacity. Test the brand to make sure they are strong and easy to close. )

Measuring spoon : ½ Teaspoon

Measuring cup : 1 cup (with ½ cup marking)

Optional (you can substitute or workaround):

Permanent marker for writing on bags

Aluminum pie plate 8”, or small loaf pan for baking

Oil (for greasing the pan, but can also be an ingredient to experiment with adding to the recipe)

Step 1: Background

Yeast are single-celled organisms (a fungus) and reproduce rapidly when they have the right environment and food. (When we talk about yeast growing, we are really talking about them multiplying: more cells, not larger cells.) Like us, yeast needs food. Like us, they give off carbon dioxide as a waste product. Our bodies have complex systems for digesting food, bringing food to the cells, and removing carbon dioxide. Yeast are much simpler: each cell absorbs food and gives off carbon dioxide directly. The bubbles of carbon dioxide make bread rise as they get trapped in the sticky dough. The carbon dioxide will also puff up the zip bags in our experiments -- showing us how much the yeast in each bag have grown.

Step 2: Introducing the Activity

Give out the bread recipe in the next step (you can bake some yourself to show). Go over the background information and have students think about what the yeast in the recipe might need to grow. Go through each ingredient and discuss whether students think the yeast might need it. If it does not seem like something yeast would need, what other roles might this ingredient play in the recipe? The science behind bread baking is actually quite complex, at this point just come up with some good hypotheses -- we will test them in a moment.

How can you test to see what ingredients the yeast need? You can mix just a few of the ingredients in a bag and watch what happens. Discuss with the students what combinations to try. For now, keep to the amounts given in the recipe and only change the combinations of ingredients (in later iterations students may want to try varying the amounts.) Design a data sheet with the students (or use our sample) to have each student keep track of their results, either separately or on one shared document. Ideally, each student should do several experiment bags and one full recipe which they can then bake and eat.

Attachments

Step 3: A Basic Bread-in-a-Bag Recipe

Ingredients : Yeast: ½ Teaspoon

Sugar: 1 Teaspoon

Salt: ½ Teaspoon

Flour: 1 cup

Water: ½ cup

To make the bread:

1: Put all the dry ingredients in the bag. Close the bag and shake to mix well.

2: Add the water. As you close the bag, lay the bag flat so as to trap as little air as possible. Gently mush it around until everything is well mixed and there are no lumps.

3: Put the bag in a tray or pot that will not be damaged if the bag leaks, and keep it out of the cold. Turn the bag occasionally, and observe what is happening over the day.

4: After about 4 hours, remove the dough from the bag and put it on a baking sheet, pie plate, or in a muffin pan (ideally grease the pan with a little oil, butter, or shortening).

5: Bake at 350 degrees for approximately 45 minutes (you can bake the bread in a regular oven or a toaster oven). When done, the bread should be a bit brown on the sides and top. Get an adult to help with the baking.

The result is a very simple bread. How could we improve the recipe?

Step 4: Suggestions

• Since the yeast needs time to grow, start the experiment in the morning, and discuss the results in the afternoon. The full recipe should be ready to bake in 4 hours, the dough will be bubbly, and the bag puffed up. If not, you can let it sit longer.
• Not everyone needs to try every combination, but do have several students try each combination. The results may vary based on additional variables such as temperature, small differences in amounts, or mistakes. Discuss the different results. Scientists usually try many replications to refine their experimental approach and results.
• Include one bag with just the dry yeast. It is a good control to compare with the other bags.
• Make sure students observe their bags often: there is lots to see as the yeast starts to grow. Record observations and times on the datasheet.
• Students will ideally come up with other variables to test based on their observations over the first day. For example, the temperature may affect how fast the yeast grow; if the water is too hot it can kill the yeast; what would happen if you vary the quantity of the ingredients; what happens if you add more sugar after the yeast have stopped growing? Plan on following up on these investigations over subsequent days.
• Students will probably not get all the variables perfectly sorted out at first -- for example, if students change two variables at once, say sugar and temperature, they will not know if it was the heat and/or the sugar that affected the results. Let students make some mistakes and discuss them -- these are good ways to learn about how science works!
• Using what you have learned, try improving the recipe. Have students talk to their parents, grandparents, or others to get more ideas (there are different bread traditions in every culture). Share the ideas. Have everyone come up with their own improved bread recipe.
• You may need to modify the recipe if a student has food allergies, and baking should be done with adult supervision.

Step 5: Resources

This Exploratorium page provides a summary of bread science and will lead you to many further references, as well as some follow up experiments for yeast, and other food science investigations:

https://www.exploratorium.edu/cooking/bread/bread....

Another Bread in a Bag recipe (there are many others on the web, including no-knead and kneaded versions):

https://www.instructables.com/No-Knead-Bread-in-a-...

Math and bread (and notes on why the amount of water matters): https://www.instructables.com/Metric-Bread/

Video of budding yeast cells:

https://www.youtube.com/watch?v=GFEgB_ytDZY

This work is made possible by support from STAR, a Biogen Foundation Initiative. The team at Lesley supporting this initiative includes faculty and staff in the Lesley STEAM Learning Lab, Science in Education, the Center for Mathematics Achievement, and other related Lesley University departments and programs.

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Yeast Alive! Watch Yeast Live and Breathe

Bring Science Home: Activity 6

By Katherine Harmon

Key concepts Life Food Metabolism

From National Science Education Standards : Life cycles of organisms

Introduction Have you ever looked closely at a piece of sandwich bread— really closely? Notice all of those tiny holes? They probably got there thanks to tiny living organisms called yeast. Even though these organisms are too small to see with the naked eye (each granule is a clump of single-celled yeasts), they are indeed alive just like plants, animals, insects and humans. In fact, we have some interesting things in common with these little creatures!

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When you breathe out, part of what you are exhaling is a gas known as carbon dioxide. Yeast also releases carbon dioxide when it is active (although it's way too small and simple an organism to have lungs). Yeast are so small you can't see individual ones very well. So how can you tell if they are alive or not? You can enlist a whole bunch of them to blow up a balloon for you!

Background When you buy a packet of baker's yeast at the store, the organisms inside are in a state of inactivity so they don't need to eat (keeping them cool and dry helps keep them preserved this way). But when you mix them into dough, they wake up and begin eating—and making carbon dioxide.

When you make yeast-based bread, you often have to wait for it to rise. During this step the dough might appear to be growing. But what is really happening is that you're giving the tiny yeast organisms time to eat and create small pockets of carbon dioxide inside the dough, which is what makes the dough seem to grow larger—and which leads to fluffy bread! (Bread products that don't have yeast rise during baking thanks to other ingredients, such as baking powder.)

Why do the yeast organisms "wake up" when you put them into a dough mixture? Like other living organisms, they need food and water. So by putting them in a moist environment with nutrients (such as sugar), they become "active."

Materials •    Fresh packet of baker's yeast (check the expiration date) •    Tablespoon of sugar •    Clear plastic bottle with a small opening (such as a water bottle) •    Funnel •    Small balloon •    Warm water

Preparation •    Carefully stretch out the balloon by blowing it up a few times (might as well give the tiny yeast a hand!). •    Pour an inch or two of warm water into the clear plastic bottle.

Procedure •    Pour the packet of yeast into the bottle and swirl it around. •    Now add the sugar, and swirl the mixture around a little bit more. •    Stretch the balloon opening over the top of the plastic bottle. •    Look through the bottle— do you see any signs of life? •    Leave the balloon-covered, yeast-filled bottle in a warm place for 15 or 20 minutes. •    Any signs of life? Do you see any changes in the balloon? •    Will the yeast keep making more and more carbon dioxide? Why might it stop? •    Extra: If you have more yeast, try making a loaf of bread from scratch. You can find simple recipes—with the science behind them—on the Exploratorium's "Science of Cooking" website .

[To get the full effect for the time-lapse section in our video we used three tablespoons of yeast, three tablespoons of sugar, and we allowed the mixture to sit for 40 minutes.] Read on for observations, results and more resources.

Observations and results When the yeast get warm water and some food to eat (in the form of sugar), they will become active. And as they eat the sugar and break it down for food, they release carbon dioxide, which fills up the balloon.

Yeast is actually a type of fungus related to mushrooms. The type of yeast used for baking is usually Saccharomyces cerevisiae , but it is one of more than 1,000 species of yeast. Our own bodies actually have plenty of yeast species that live peacefully alongside (and inside) us!

Other foods, such as cheese, also make use of tiny creatures and their little life cycles. Instead of yeast, cheese is brought to you in part by bacteria—but these are carefully controlled and healthful types of bacteria, so no need to worry about eating it.

Share your living yeast observations and results! Leave a comment below or share your photos and feedback on Scientific American 's Facebook page .

Cleanup Rinse out the bottle and recycle or reuse it. Reuse the balloon.

More to explore "Yeast Does DNA Tricks to Live in Us" from Scientific American "Mixed Cultures: Art, Science and Cheese" from Scientific American "Bread Science 101" overview from the Exploratorium "Microorganisms" overview from the Children's University of Manchester I'm a Scientist: Kitchen by DK Publishing, ages 4–8 The Science Chef: 100 fun food experiments and recipes for kids by Joan D'Amico, ages 9–12

Up next… Sink or Swim: Muscle Versus Fat

What you'll need •    Cooked piece of meat that has both lean meat and fat on it (such as a pork chop or steak) •    Knife to cut the meat •    Piece of bread •    Large clear glass cup or bowl •    Water

SCIENCE OF YEAST

We are pleased to offer a comprehensive and convenient resource on yeast. “The Science of Yeast” covers a broad range of subjects – from the history of yeast to the modern yeast manufacturing process. Educator and student resources are also available, including science project experiments.

Use the links below to go to a topic.

EDUCATION RESOURCES

What is yeast, what is yeast.

Yeast is a fascinating, living organism that turns a mixture of flour and liquid into something amazing that rewards your efforts with wonderful aromas and complex flavors that only yeast can deliver.

Yeast is a single-celled living organism with a mighty big job in baking. Yeast cells are so small that one (0.25-ounce) packet of dry yeast contains billions of healthy yeast cells!

Yeast cells digest food to obtain energy for growth. Their favorite food is sugar in its various forms: sucrose (beet or cane sugar), fructose and glucose (found in white sugar, honey, molasses, maple syrup and fruit), and maltose (derived from starch in flour).

The process, alcoholic fermentation , produces useful end products, carbon dioxide (gas) and ethyl alcohol. These end products are released by the yeast cells into the surrounding liquid in the dough. In bread baking, when yeast ferments the sugars available from the flour and/or from added sugar, the carbon dioxide gas cannot escape because the dough is elastic and stretchable. As a result of this expanding gas, the dough inflates, or rises. Thus, the term “yeast-leavened breads” was added to the vocabulary of the world of baking.

The ethyl alcohol (and other compounds) produced during fermentation produce the typical flavor and aroma of yeast-leavened breads.

Yeast in History

Yeast can be considered man’s oldest industrial microorganism. It’s likely that man used yeast before the development of a written language. Hieroglyphics suggest that the ancient Egyptian civilizations were using yeast and the process of fermentation to produce alcoholic beverages and to leaven bread over 5,000 years ago. The biochemical process of fermentation that is responsible for these actions was not understood and undoubtedly looked upon by early man as a mysterious and even magical phenomenon.

Leaven, mentioned in the Bible, was a soft, dough-type medium kept from one bread baking session to another. A small portion of this dough was used to start or leaven each new lot of bread dough.

It is believed that since early times, leavening mixtures for bread making were formed by natural contaminants in flour such as wild yeast and lactobacilli, organisms also present in milk.

Yeast Today

It was not until the invention of the microscope, followed by the pioneering scientific work of Louis Pasteur in the late 1860’s, that yeast was identified as a living organism and the agent responsible for alcoholic fermentation and dough leavening. Shortly following these discoveries, it became possible to isolate yeast in pure culture form. With the newfound knowledge that yeast was a living organism and the ability to isolate yeast strains in pure culture form, the stage was set for commercial production of baker’s yeast that began around the turn of the 20th century.

See yeast manufacturing diagram and video here .

YEAST TYPES

• Baker’s Yeast
• Nutritional Yeast
• Wine and Distiller’s Yeast
• Brewer’s Yeast

Baker’s yeast is used in home and commercial bread baking to leaven dough. It is widely available in these forms: Cream Yeast, Fresh Yeast (also known as wet, cake, crumbled or compressed yeast), Active Dry Yeast and Instant (quick-rising or fast-rising) Yeast.

Click image below for more information on our products for home baking.

For information on Commercial Baking or Food Service Yeast and Ingredients, click here .

Nutritional yeast is dried, inactive yeast that is an excellent source of protein, rich in many essential amino acids. It is not an active (alive) yeast product, and cannot leaven dough.

Visit Gnosis by Lesaffre for more information or inquiries about nutritional yeast.

Wine and distiller’s yeast are sold through Fermentis , another business unit of Lesaffre.

Brewer’s yeast is a by-product of the brewing industry. Lesaffre Corporation does not sell Brewer’s Yeast. Alternatively, Lesaffre produces Nutritional Yeast .

INFORMATION FOR EDUCATORS

Red Star Yeast is pleased to offer comprehensive and convenient resources for the classroom. It is our hope that you will find these resources on this page and website of great benefit in your classroom and, in turn, generate a positive interest in your students in yeast, yeast products and baking with yeast.

We also offer special educator prices for thermometers and our yeast products for use in classroom baking activities and experiments. Download our Educator’s Order Form here .

Additional classroom resources:

Explore Yeast

Home Baking Association

INFORMATION FOR STUDENTS

So, you’ve been assigned by your teacher to do a science fair project and you’re looking for some ideas? Come Explore the Science of Yeast!

• Yeast experiments
• What is Yeast
• Types of Yeast
• How Yeast is Made
• Explore Yeast.com

– CLASSROOM and SCIENCE FAIR –

YEAST EXPERIMENTS

Use these experiments as a guide or modify with your own variables.

• Growth #1 – Sugar and Yeast
• Growth #2 – Is Yeast Alive?
• Fermentation #1 – Ingredients
• Fermentation #2 – Temperature
• Making Bread #1 – Does Salt Affect Bread?
• Making Bread #2 – Does Sugar Affect Bread?

HOW YEAST IS MADE

Step-by-step diagram and video on how we grow baker’s yeast.

Download HERE .

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The Fresh Loaf

A community of amateur bakers and artisan bread enthusiasts., search form, you are here, the science behind bread (experiment).

White Bread

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Intro- In our Biology class, we made bread in order to better understand photosynthesis and cellular respiration. We are novices in the bread making business and we were tasked with figuring out the necessary ingredients and the amount of each ingredient as well as the science behind bread making.

Yeast are actually living organisms! They are eukaryotic, single-celled organisms. Yeast plays a very important role in bread making. Yeast is capable of converting sugar into carbon dioxide and alcohol. In doing this, it causes the bread to rise. The warm water added to the dough “activates” the yeast. If the water is too hot, it will kill the yeast. If the water is not hot enough, the yeast will not wake up.

Cellular Respiration

The process yeast uses to make carbon dioxide and alcohol is called alcoholic fermentation. This process is a variation of cellular respiration, or the process of turning oxygen and sugar into energy, carbon dioxide, and water. Cellular respiration takes place in the mitochondria and it is used by humans and all other organisms to make energy.  The chemical equation for cellular respiration is 6O2+ C6H12O6 → 6H2O+ ATP+ 6O2. There are two types of  respiration: aerobic, which requires oxygen, and anaerobic, which does not. Within anaerobic respiration there is alcoholic fermentation for plants and lactic acid fermentation for animals.

Flour was wheat before it became flour. Wheat is a plant, and like all other plants it goes through photosynthesis. In the process of photosynthesis, glucose and oxygen is made from carbon dioxide and water. Although the flour no longer performs photosynthesis, when it was turned into flour some glucose that was produced was most likely left behind. Since yeast uses glucose to perform alcoholic fermentation and make the bread rise, the flour can be used as its “food” along with sugar. Flour is made up of glutenin and gliadin. When combined with warm water, the glutenin and gliadin turn into gluten. This is important in bread making because it strengthens the bread and provides structure.

Carbon Cycle

Making bread also plays a role in the carbon cycle. Because anaerobic respiration is being performed, carbon dioxide is being produced. Therefore, when bread is made, carbon dioxide is released into the air.

The Science Behind the Ingredients

Originally, our team was given a simplistic recipe for plain, white bread. This recipe involved flour,  120 degree water and yeast. Our job was to add ingredients that would produce better bread and understand the science behind what made those ingredients work well.

Butter- Based off of research, butter makes bread more tender and increases elasticity. It also adds a lot of flavor. However, it can cause the bread to rise slightly slower so we decided to only put ½ Tbsp of butter in our recipe. We figured this way we could still get the flavor without the negative effects on the rising speed.

Salt- Salt is another preference ingredient we chose to add. Like butter, it adds flavor but it also decreases rising time. We added only a pinch of salt to our recipe because we know that a little bit of salt goes a long way in terms of flavor. Also, we didn’t want the decrease the rising speed.

Sugar- Sugar, or glucose, is food for the yeast. Therefore, adding sugar will increase rising time. In our research we found that you should not add more that 2 teaspoons per cup of flour. Based off of that proportion, we could add up to 1 teaspoon of sugar. We chose to add ¼ teaspoon because we wanted to play it safe, and we didn’t want really sweet bread.

Before we made our final product, we had a day to experiment with and tweak our created recipe. We did not bake our experimental bread, but we monitored its rising time for 30 minutes. There was a control bread that we compared our bread to. The control bread was made with only flour, yeast, and water. We were very happy with the results of the our bread. It rose slightly more than the control bread and when we broke it apart after 30 minutes of rising, it had lots of holes which meant that alcoholic fermentation occurred. We decided not to change our recipe at all because we had good results.

Now that you understand the science behind bread making, here is the procedure we followed:

In a ziploc baggie, mix together ¼ teaspoon yeast and ¼ cup of flour

Heat 4 tablespoons of water to 120 °F - 130 °F (1 minute in the microwave). Then slowly add the 4 tablespoons of heated water to the baggie and stir to combine.

                        Add ¼ teaspoon of sugar

Let mixture sit for 10 minutes in order for the yeast to activate.

Mix another ¼ cup of flour into the baggie

Add ½ Tbsp of butter and a pinch of salt to the baggie

Take the dough out of the baggie and knead it for one minute.

Roll the dough into a ball

Place the dough ball under a heat lamp for 30 minutes.

Place the dough ball in a cupcake pan and bake for 15 minutes in 375 degrees.

Here is our final product!

We were successful in making bread, however it did not turn out how we thought it would. It was very hard, dry and bland. We had the right ingredients but not the right amount. If we were to do this again we would use more butter for flavor, and a little bit more sugar to make the bread rise more. Overall, we consider this bread to be a failure. Although it looked delicious and smelled delicious, it tasted like cardboard. However, we learned a lot in the process. If we were to make bread again, it would turn out a lot better.

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Too little salt will make your bread taste insipid. Aim for about 2% of salt in your recipe. You won't need to increase the butter or sugar. 

• Schmid College of Science and Technology

Simple Science: Making Bread In A Bag Food Science Professor Anu Prakash offers a fun and simple way for kids to make bread in a zip lock bag.

October 7, 2016

Did you know that Chapman recently broke ground on its most innovative building to date? The 140,000 square-foot Center for Science and Technology is the manifestation of Chapman’s ongoing commitment to scientific advancement and discovery. Get your future Panthers in the scientific spirit with this engaging and silly experiment, recommended by Chapman’s own Anu Prakash, Director of Schmid College’s Food Science program.

Making bread is an age old tradition, one that is traditionally associated with being long and arduous. But making bread can be fun, and can provide insight into the science of baking and how yeast works. If you are making bread as a microorganism experiment, vary the yeast, sugar, salt, or water temperature for interesting results! We had Food Science graduate student Erika Orejola, and 6-year old Rasa Nazarinia, put the experiment to the test and they delivered some delicious results!

We had @cufoodscience student Erika Orejola and 6-year old Rasa Nazarinia make bread in a bag as part of our “Simple Science” series, which delivers science for kids! Check the Schmid Blog to learn more and find the recipe! A video posted by Chapman Sciences (@chapmansciences) on Oct 7, 2016 at 8:54am PDT

 Materials:

• 3 Cups flour, divided into three 1 cups
• 1 (.25) package rapid rise yeast
• 3 Tbsp white sugar
• 3 Tbsp olive oil
• 1 Cup warm water
•  1.5 tsp salt

1. In a resealable Zip Lock bag combine 1 cup of flour, sugar and yeast and add in warm (not hot) water.

3. Let the dough sit for 10 minutes at room temperature.

4. Open the bag and add 1 cup of flour, the oil and the salt.  Remove the air from the bag, seal it and squish again.

6. Continue mixing until well blended.

7. Remove the dough from the bag and put on a lightly floured surface.

8. Knead the dough for 8 minutes until it becomes smooth.

9. Divide the dough and place each into lightly greased bread pans or feel free to construct it into a fun shape (we suggest “C” and “U” for Chapman University!)

10. Cover the pan with a towel and allow to rise for about 45-60 minutes. The bread should double in size.

11. Bake in a 375 degree oven for 25 minutes or until golden brown.

12. Let the bread cool and enjoy!

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Chapman Students Advocate for Higher Education at State Capitol

May 7, 2024 by Staci Dumoski | Student Focus

Participants in a six-month internship program met with Assemblymember Avelino Valencia and others to win support for increased Cal-Grant funding for students enrolled at private universities.

Chapman University’s Yakir Aharonov Elected as Member of the Royal Society

May 28, 2024 by Katy Gilbertson | News

Yakir Aharonov, a professor at Schmid College of Science and Technology and holder of the James J. Farley Professorship in Natural Philosophy, has been elected as a member of the Royal Society, the UK’s national academy of sciences.

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Week 3: Sugar, yeast and life

Introduction

Welcome to Week 3. This week, you will be conducting experiments using living organisms. You might be wondering if you need special licences or ethics committee approval, but as the organisms involved are only single-celled fungi, you don’t need to worry. This week, you will be experimenting on yeasts.

As single-celled organisms, yeasts are tiny; only a few, to a few tens, of micrometres (10 -6  m) across. Yet despite their size, they have had a huge impact on our culture, having been used for thousands of years in the manufacture of leavened bread, beer and wine (although some of us think it reached its culinary peak in the manufacture of Marmite).

The uses we have put yeasts to might seem trivial, but for many centuries throughout the history of human culture, water supplies were often unsafe to drink, due to the presence of pathogens. It was often the case that the only safe beverage to drink was beer or wine, so the use of yeasts has been pivotal in lowering mortality rates.

3.1 Experiment 4: Yeast experiment

Living organisms, like yeasts, need food and oxygen in order to survive and thrive. In this experiment, you will test some conditions that can affect their growth. What variables might you be able to change in this experiment?

You will add the living yeast organisms to sugary solutions at different temperatures. You will also cover one glass of your sugary solution with cling film.

To carry out this experiment, you will need:

• four glasses
• four sachets of baker’s yeast
• a marker pen
• your  activity booklet .

As with experiments in the previous weeks, you will want to carry this out somewhere that it won’t be disturbed by family members or pets. The experiment shouldn’t take more than half an hour or so to carry out, so you won’t need to be vigilant for too long.

What results do you expect to see in this experiment? Try to write down a hypothesis that you will be testing.

3.1.1 The experiment

Follow Janet’s instructions in the video (or use your  activity booklet   PDF) to conduct the experiment. You will need about 1 tablespoon of sugar and approximately 200 ml of water in each large glass. This sugar will act as food for your yeasts to consume.

Take care to label your glasses with which variables you’ve changed – you don’t want to get them mixed up. If the environmental conditions are suitable, the yeasts will grow and multiply quite quickly – you shouldn’t need more than 30 minutes to complete this experiment. Remember that boiling water can crack glassware, so be careful to let the water cool a bit first.

Carefully observe and record which glasses have conditions suitable for the yeasts to grow and which ones have conditions that restrict its growth.

You will have the opportunity to discuss your results in the next section.

3.1.2 What were your results?

You should now have completed this week’s experiment and be ready to share your findings with your fellow learners.

Activity 3.1 Experiment 4

Post your results and findings in the course forum thread for this activity

• Were your results similar to Janet’s or were there any differences?
• Which environments promoted yeast growth and what environments hindered yeast growth?
• How do the results of your two experiments at body temperature conditions compare?
• Did you notice any changes with time? If you needed to, how could you display these results?

While it is nice when an experiment goes according to plan, it is often more interesting from a scientific point of view when something odd and unexpected happens. It usually means that there is something exciting going on, or that you need to think about ways to tighten up your experimental skills – both of which are good things. Never feel bad if an experiment goes a bit wonky, that is where the cutting edge stuff happens!

3.1.3 Yeast experiment explained

You’ve seen the results of the yeast experiment, but what do these results mean?

Yeasts are microscopic, single-celled organisms, and are a type of fungus that is found all around us, in water, soil, on plants, on animals and in the air. Like all organisms, when yeasts are put in the right type of environment they will thrive; growing and reproducing.

Your experiments were designed to help you identify which environment promotes the most yeast growth. The first three glasses in your experiment contained different temperature environments (cold water, hot water and body temperature water). At very low temperatures the yeast simply does not grow but it is still alive – if the environment were to warm up a bit, it would gradually begin to grow. At very high temperatures the cells within the yeast become damaged beyond repair and even if the temperature of that environment cooled, the yeast would still be unable to grow. At optimum temperatures the yeast thrives.

Your third and fourth glasses both contained environments at optimum temperature (body temperature) for yeast growth, the difference being, the fourth glass was sealed. The variable between these two experiments was the amount of available oxygen. You may have been surprised by your results here, thinking that a living organism in an environment without oxygen cannot survive? However, you should have found that yeast grew pretty well in both experiments.

To understand why yeast was able to thrive in both conditions we need to understand the chemical process occurring in each glass during the experiment. In the three open glasses, oxygen is readily available, and from the moment you added the yeast to the sugar solution it began to chemically convert the sugar in the water and the oxygen in the air into energy, water, and carbon dioxide in a process called aerobic respiration.

Yeast is a slightly unusual organism – it is a ‘facultative anaerobe’. This means that in oxygen-free environments they can still survive. The yeast simply switches from aerobic respiration (requiring oxygen) to anaerobic respiration (not requiring oxygen) and converts its food without oxygen in a process known as fermentation. Due to the absence of oxygen, the waste products of this chemical reaction are different and this fermentation process results in carbon dioxide and ethanol.

Depending on how long you monitored your experiment for and how much space your yeast had to grow you may have noticed that, with time, the experiment sealed with cling film slowed down. This is for two reasons; firstly because less energy is produced by anaerobic respiration than by aerobic respiration and, secondly, because the ethanol produced is actually toxic to the yeast. As the ethanol concentration in the environment increases, the yeast cells begin to get damaged, slowing their growth.

The ethanol produced is a type of alcohol, so it is this process that allows us to use it to make beer and wine. When used in bread making, the yeast begins by respiring aerobically, the carbon dioxide from which makes the bread rise. Eventually the available oxygen is used up, and the yeast switches to anaerobic respiration producing alcohol and carbon dioxide instead. Do not worry though; this alcohol evaporates during the baking process, so you won’t get drunk at lunchtime from eating your sandwiches.

3.2 Altering variables

You have now conducted another experiment, one which had several different variables. Variables are parts of an experiment that can be kept the same, or changed in order to test different outcomes.

In the yeast experiment, you actually performed two separate tests at the same time; one regarding the temperature and another regarding available oxygen. Note that in each case you only altered one variable (either temperature or oxygen availability).

You could repeat the yeast experiment, keeping both temperature and oxygen availability constant but altering a different variable, i.e., fixing a previously changing variable and changing a previously fixed variable. By performing a combination of these experiments the optimum conditions for yeast growth can be determined.

You should now be starting to think like an experimental scientist and considering ways that an experiment can be altered so that different hypotheses can be tested.

Takes some time now to think which other variables you could test and why.

3.3 Yeast – who needs it?

You’ve seen yeast in action and had a look at the science behind it, but where has it come from? Human society has used it for at least 7000 years. Its use in brewing is first thought to have taken place in ancient Iran and possibly even earlier in China. The oldest surviving beer recipe dates back to a 3900-year-old Sumerian poem.

The earliest brewing may well have been accidental, as wild yeasts in the air and on the ground may have contaminated cereal crops, causing them to undergo spontaneous fermentation, possibly in leftover pots of gruel. As time passed these brews would have been replicated and, to a degree, standardised.

Without fermented beverages, historical populations might have been afflicted with more waterborne diseases than are recorded, due to the boiling step in the production process.

Around the same time yeasts were being used in brewing, they began to be used as raising agents in bread making. As far back as 30,000 years ago, humans were crushing up cereal crops and baking them as flatbreads, but records show that from a few thousand years ago the ancient Egyptians began using yeasts to leaven bread, although the extent to which their rather dense loaves actually rose is uncertain.

The Romans, Greeks, Gauls, and Iberians are all recorded as making leavened breads. By the Middle Ages bread had become a staple across Europe, not only as food, but also as a type of plate, known as a trencher. These trenchers were made from a slice of stale bread, on which the food was placed. The trencher would soak up the juices to be eaten later or given to the poor.

In modern times, bread comes in a dizzying array of types, light to dark, pure and refined, coarse and grainy, sliced and unsliced to name but a few. Interestingly, sliced bread is a fairly recent invention.

Early attempts to pre-slice bread were met with doubt as it was thought that the bread would go stale too quickly. In 1928, Otto Rohwedder sold his latest invention to a bakery in Chillicothe, Missouri, a device to slice and wrap loaves of bread. In 1928, an advert was run on the back page of the local newspaper proclaiming it to be ‘the greatest forward step in the baking industry since bread was wrapped’. This may be the origins of the phrase, ‘the best thing since sliced bread’, suggesting that the best thing prior to sliced bread was wrapped bread!

3.4 Week 3 quiz

Check what you’ve learned this week by taking this end-of-week test.

Complete the Week 3 quiz   now.

Open the quiz in a new window or tab then come back here when you're done.

3.5 Week 3 summary

Congratulations on completing Week 3. Who knew yeast was so important in human history?

While the experiments you’ve carried out over the last three weeks have been necessarily simple enough for you to perform at home, with little risk of accidentally constructing a doomsday device or incinerating your pets or family, they are important experiments in explaining how the world around us works. Hopefully, you’ve also developed skills in carrying out scientific experiments and how you can identify and alter variables to test a hypothesis further.

In the final week of the course, the difficulty level ramps up a notch, as you will be using some household items to separate and extract the DNA from a living organism!

To conduct next week’s experiment, you will need:

• kiwi fruit (or another fruit of your choice)
• methylated spirits, chilled in freezer for 30 minutes (or vodka or strong white rum)
• fine sieve or filter paper
• washing-up liquid
• measuring beaker
• a paperclip.

Remember, methylated spirits are extremely hazardous and should only be used with adult supervision.

You can now go to Week 4 .

Acknowledgements

This course was written by Hazel Rymer.

Except for third party materials and otherwise stated in the acknowledgements section, this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence .

Every effort has been made to contact copyright owners. If any have been inadvertently overlooked, the publishers will be pleased to make the necessary arrangements at the first opportunity.

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Bread Dough Rising Experiment

Science is all around us.

Oftentimes, we apply the principles of physics, chemistry or biology without even knowing.

We can all be scientists and we are  by observing and studying carefully what happens around us.

Baking is a good example.

Kids love baking and playing with the dough.

Making bread with kids is full of teaching moments.

Try this science of break making experiment.

The Science of Bread Baking

Let's do this  edible experiment together and see what kids can learn at each step.

• 1/3 package active dry yeast
• 3/4 cup warm water
• 1 tablespoon sugar
• 2 1/4 cup all purpose flour
• 1/3 tablespoon salt
• 2/3 tablespoon cooking oil (e.g. canola oil) or butter
• adult supervision

Instructions

• In a large bowl, dissolve yeast and sugar in warm water.
• Learn how to measure.

• Stir gently and put aside for 15 mins or until you will see a layer of foam form on the surface.
• Once reactivated in warm water, yeast begins feeding on the sugars and releasing carbon dioxide . The carbon dioxide forms a layer of small bubbles on the water surface. This is called  anaerobic fermentation .

• Add salt, oil 2 cups of flour.
• Beat until smooth.
• Then stir in enough remaining flour, a little bit at a time, to form a soft dough.
• Turn onto a floured surface. Knead until smooth and elastic, about 8-10 minutes.

• Place in a greased bowl, turning once to grease the top.
• Cover with a wet towel and let it rise in a warm place until doubled, about 30 minutes to 1 hour.
• Remember yeast is only active in warm water? Yeast needs a warm and moist environment to ferment.

• Punch dough down. Turn onto a lightly floured surface; divide dough into smaller doughs.
• Notice when you punch down the dough, its size shrinks. That's because the strands of gluten are still soft and cannot hold in shape to preserve the space inside when they're under pressure.
• Punching down removes some of the gas bubbles formed during rising and produces a finer grain. It also redistributes the yeast cells, sugar and moisture so they can ferment and rise the dough during the proofing stage.

• Bake at 375° for 30-35 minutes or until golden brown. Check occasionally to prevent burning.
• Move the loaves from the pan to wire racks to cool.
• Study the size of the bread loaves.
• Carbon dioxide, like most gases, expands when it is heated. In the oven, air pockets inside the bread expand and caused the bread to increase further in size ( oven spring ). That is why the bread is larger in size than the bread dough that went in.
• Break up a piece and observe the small holes inside.

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Not only was it fun, but the experiment was also tasty . My daughter refused to share her two big pieces of bread, which was a very good indication that the baking was a success.

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• Meet baker’s yeast, the budding, single-celled fungus that fluffs your bread

Meet baker’s yeast, the budding, single-celled fungus that fluffs your bread

Dough rising in a 100-minute time-lapse animation. In bread dough, baker’s yeast, or Saccharomyces cerevisiae , digests sugar and releases carbon dioxide. The CO2 forms bubbles in the dough and causes it to expand. Credit: Douglas Levere / University at Buffalo

The pandemic has caused a run on baker’s yeast. It’s a marvelous organism, as UB scientists explain

By charlotte hsu.

Release Date: July 9, 2020

BUFFALO, N.Y. — They live in bread dough. They die in your oven.

At the grocery store, where you buy them, they sit in little glass jars, dormant on the shelf, waiting to be rehydrated so they can do their life’s work, eating sugar and releasing carbon dioxide to form bubbles in your bread.

Baker’s yeast has become a sought-after pandemic commodity as people bake at home.

But how much do you really know about this organism, a single-celled fungus that scientists call Saccharomyces cerevisiae ?

As it turns out, baker’s yeast is a common model organism that researchers use to study biological processes, including disease. A number of biologists in the University at Buffalo College of Arts and Sciences regularly grow the species in their labs, and a few took time to discuss the wacky, wonderful science of S. cerevisiae .

What is baker’s yeast? (Don’t worry —it won’t grow into a mushroom)

“Yeast is a fungus that grows as a single cell, rather than as a mushroom,” says Laura Rusche, PhD, UB associate professor of biological sciences.

Though each yeast organism is made up of just one cell, yeast cells live together in multicellular colonies. They reproduce through a process called budding, in which a “mother cell” grows a protrusion known as a “bud” that gets bigger and bigger until it’s the same size as the mom.

Baker’s yeast, or Saccharomyces cerevisiae , seen through a microscope in the lab of UB biologist Laura Rusche. Each round object is an individual yeast cell. The cells pictured are a laboratory strain of S. cerevisiae , but wild yeast look essentially the same, Rusche says. Credit: Ashleigh Hanner

“That’s the daughter cell, and it splits off,” says Sarah Walker, PhD, UB assistant professor of biological sciences. “They’re single-celled organisms, so they don’t grow to become mushrooms or anything like that.”

When food supplies run low or the environment gets harsh, S. cerevisiae can produce special stress-resistant cells called spores, which can stay dormant for long periods of time, germinating when conditions improve. Regular, non-spore yeast cells can also be preserved through freezing.

“Yeast cells can hunker down and wait — they can go into a sort of suspended animation to survive stress,” Walker says. “We can’t do it, but they can. In the lab, we put them in a -80 Celsius freezer, so it’s a deep freeze, and they are stable for years and years. Later, we take a little bit of the ice out of the frozen culture, and it starts growing again.”

What does yeast do in nature?

Out in the world, yeast is all over — on tree sap, on grape skins, on fallen fruits. The organisms drive the process of decay, helping to break down plant material.

“Where is yeast found in nature? It is found everywhere,” Rusche says. “It makes little spores, and those spores are kind of just around. Where it proliferates is on rotting vegetative matter, rotting fruit. It likes sugar.”

“For a long time, people used to lump plants and fungi together, but they’re biologically different,” she adds. “Plants do photosynthesis. Fungi don’t. Fungi live on decaying material, on things like rotting wood, and they’re eating the stuff that other organisms have left behind, whereas plants are making their own food through photosynthesis.”

Walker explains that S. cerevisiae and other yeast species eat sugar and produce byproducts including carbon dioxide (responsible for the air pockets in leavened bread), and alcohol (think wine and beer).

“Yeast evolved to take advantage of high-sugar plant material that came about when flowering plants emerged,” she says. “The plants make sweet fruits to attract animals to move their seeds around, but the fruits mostly get dropped on the ground, and they rot, and the yeast are taking advantage of all this. They’re what’s doing the rotting.”

Why do scientists use baker’s yeast in the lab?

Colonies of baker’s yeast, or Saccharomyces cerevisiae , pictured under a microscope. Yeast don’t grow this way in bread dough: The images are from a 2016 study in the lab of UB biologist Paul Cullen that explored cellular mechanisms that cause certain changes in yeast growth patterns. In glucose-rich conditions on a flat laboratory plate (left), the yeast cells grow in a tight cluster. But when glucose is limited (right), new cells grow outward, forming a filament-like configuration that may aid in the search for food. Bar, 10 microns. Credit: Paul J. Cullen

Researchers harness baker’s yeast to study a variety of biological processes.

Rusche’s lab uses S. cerevisiae to learn more about how certain genes get switched on or off in response to stress. Walker’s team uses the organism to probe the intricacies of mRNA translation, which causes cells to produce proteins.

This research sheds light on the basic biology of S. cerevisiae . But the work could also improve understanding of cellular processes in other species, ranging from disease-causing yeasts to humans.

Scientists like to work with baker’s yeast because it’s cheap, its genetic material is easy to manipulate, and researchers already know a lot about it. Yeast also grows quickly.

“Yeast cells are a good model organism because you can grow a culture overnight. Doubling time is only an hour-and-a-half, whereas if you’re growing a mammalian cell culture, it can take a few weeks,” Walker says. “A lot of the time, yeast has a pared down version of the genetic machinery that’s required for similar processes in higher organisms. So sometimes we do our initial work in yeast, and then we try to follow up on promising results in mammalian cells.”

“It’s a really well-established lab organism, so if you learn something new about Saccharomyces , you can put it in the context of everything else that the whole community has already learned about that organism. You can relate the data to what you already know,” Rusche says. “If you go to a species that hasn’t really been studied, and you make a discovery, you have a piece of information in isolation.”

Any tips for bakers and brewers?

Baker’s yeast, Saccharomyces cerevisiae , proofing with sugar and water in a ​40-minute time-lapse animation. Credit: Douglas Levere / University at Buffalo

Christopher Rupert, a PhD candidate in Rusche’s lab, says one of the neat things about yeast is that these organisms evolved not to help humans make bread and beer, but to survive in their ecological niches.

“A lot of people associate yeast with beer and bread. Yeast ferments — it takes in sugar and spits out alcohol and CO2 — and that’s why we love it so much,” he says. “But what’s interesting is that it is hypothesized that this evolved as a way for yeast to fight other micro-organisms. Yeast has a higher alcohol tolerance, so when it is secreting alcohol, it is killing bacteria around it, so it’s the only one that’s left.”

Rupert’s dissertation deals with the yeast species Candida parapsilosis , which can cause human infections. But he did undergraduate research on S. cerevisiae , and also uses it at home; he’s an avid baker, making dinner rolls, burger buns, buttermilk biscuits and sourdough bread (he seeded his with some baker’s yeast, but it also contains wild yeasts of different species).

“When we used to go into the lab, he would bring stuff in for us to sample,” Rusche says, recalling the days before social distancing. “We would always get all his treats.”

Because yeasts did not evolve specifically to help humans, humans must cater to the needs of yeasts.

For example, S. cerevisiae thrives at temperatures of about 85 degrees Fahrenheit, which is why seasoned bakers often keep their rising dough somewhere warm. Too cold, and the yeast will be slow to grow. Too hot, and it will die.

When it comes to making wine, choosing the right species of yeast can be important, as some can tolerate higher levels of alcohol than others. If your yeast dies before it’s able to consume all of the sugar, your beverage might turn out too sweet, says Walker, who has a peach tree in her yard and makes peach wine.

“If you bake or brew with yeast, you have a living organism. You have to give it time and a nice warm environment,” Rusche says. “Humans domesticated Saccharomyces cerevisiae , but there are so many different species of yeast in the world. Sourdoughs contain a lot of wild yeast, and many of those are not Saccharomyces . They’re such interesting organisms.”

Media Contact Information

Charlotte Hsu is a former staff writer in University Communications. To contact UB's media relations staff, email  [email protected]  or visit our list of current university media contacts .

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Why do scientists use baker’s yeast in the lab?

Baker's Yeast in lab measuring cup

Why do scientists use baker’s yeast in the lab? Researchers harness baker’s yeast to study a variety of biological processes. Laura Rusche’s lab uses  S. cerevisiae  to learn more about how certain genes get switched on or off in response to stress. Sarah Walker’s team uses the organism to probe the intricacies of mRNA translation, which causes cells to produce proteins. Paul Cullen's lab explores cellular mechanisms that cause certain changes in yeast growth patterns.  Read the news article by Charlotte Hsu . 

Research News

Meet baker’s yeast, the budding, single-celled fungus that fluffs your bread.

Dough rising in a 100-minute time-lapse animation. In bread dough, baker’s yeast, or Saccharomyces cerevisiae, digests sugar and releases carbon dioxide. The CO2 forms bubbles in the dough and causes it to expand. Photo: Douglas Levere

By CHARLOTTE HSU

Published July 13, 2020

They live in bread dough. They die in your oven.

At the grocery store, where you buy them, they sit in little glass jars, dormant on the shelf, waiting to be rehydrated so they can do their life’s work, eating sugar and releasing carbon dioxide to form bubbles in your bread.

Baker’s yeast has become a sought-after pandemic commodity as people bake at home.

But how much do you really know about this organism, a single-celled fungus that scientists call Saccharomyces cerevisiae ?

As it turns out, baker’s yeast is a common model organism that researchers use to study biological processes, including disease. A number of biologists in the College of Arts and Sciences regularly grow the species in their labs, and a few took time to discuss the wacky, wonderful science of S. cerevisiae .

What is baker’s yeast?

“Yeast is a fungus that grows as a single cell, rather than as a mushroom,” says Laura Rusche, associate professor of biological sciences.

Though each yeast organism is made up of just one cell, yeast cells live together in multicellular colonies. They reproduce through a process called budding, in which a “mother cell” grows a protrusion known as a “bud” that gets bigger and bigger until it’s the same size as the mom.

“That’s the daughter cell, and it splits off,” says Sarah Walker, assistant professor of biological sciences. “They’re single-celled organisms, so they don’t grow to become mushrooms or anything like that.”

When food supplies run low or the environment gets harsh, S. cerevisiae can produce special stress-resistant cells called spores that can stay dormant for long periods of time, germinating when conditions improve. Regular, non-spore yeast cells can also be preserved through freezing.

“Yeast cells can hunker down and wait — they can go into a sort of suspended animation to survive stress,” Walker says. “We can’t do it, but they can. In the lab, we put them in a -80 Celsius freezer, so it’s a deep freeze, and they are stable for years and years. Later, we take a little bit of the ice out of the frozen culture, and it starts growing again.”

What does yeast do in nature?

Baker’s yeast, or Saccharomyces cerevisiae , seen through a microscope in the lab of UB biologist Laura Rusche. Each round object is an individual yeast cell. The cells pictured are a laboratory strain of S. cerevisiae , but wild yeast look essentially the same, Rusche says. Photo: Ashleigh Hanner

Out in the world, yeast is all over — on tree sap, on grape skins, on fallen fruits. The organisms drive the process of decay, helping to break down plant material.

“Where is yeast found in nature? It is found everywhere,” Rusche says. “It makes little spores, and those spores are kind of just around. Where it proliferates is on rotting vegetative matter, rotting fruit. It likes sugar.”

“For a long time, people used to lump plants and fungi together, but they’re biologically different,” she adds. “Plants do photosynthesis. Fungi don’t. Fungi live on decaying material, on things like rotting wood, and they’re eating the stuff that other organisms have left behind, whereas plants are making their own food through photosynthesis.”

Walker explains that S. cerevisiae and other yeast species eat sugar and produce byproducts including carbon dioxide (responsible for the air pockets in leavened bread) and alcohol (think wine and beer).

“Yeast evolved to take advantage of high-sugar plant material that came about when flowering plants emerged,” she says. “The plants make sweet fruits to attract animals to move their seeds around, but the fruits mostly get dropped on the ground, and they rot, and the yeast are taking advantage of all this. They’re what’s doing the rotting.”

Colonies of baker’s yeast, or Saccharomyces cerevisiae , pictured under a microscope. Yeast don’t grow this way in bread dough: The images are from a 2016 study in the lab of UB biologist Paul Cullen that explored cellular mechanisms that cause certain changes in yeast growth patterns. In glucose-rich conditions on a flat laboratory plate (left), the yeast cells grow in a tight cluster. But when glucose is limited (right), new cells grow outward, forming a filament-like configuration that may aid in the search for food. Photo: Paul J. Cullen

Researchers harness baker’s yeast to study a variety of biological processes.

Rusche’s lab uses S. cerevisiae to learn more about how certain genes get switched on or off in response to stress. Walker’s team uses the organism to probe the intricacies of mRNA translation, which causes cells to produce proteins.

This research sheds light on the basic biology of S. cerevisiae . But the work could also improve understanding of cellular processes in other species, ranging from disease-causing yeasts to humans.

Scientists like to work with baker’s yeast because it’s cheap, its genetic material is easy to manipulate, and researchers already know a lot about it. Yeast also grows quickly.

“Yeast cells are a good model organism because you can grow a culture overnight. Doubling time is only an hour-and-a-half, whereas if you’re growing a mammalian cell culture, it can take a few weeks,” Walker says. “A lot of the time, yeast has a pared-down version of the genetic machinery that’s required for similar processes in higher organisms. So sometimes we do our initial work in yeast, and then we try to follow up on promising results in mammalian cells.”

“It’s a really well-established lab organism, so if you learn something new about Saccharomyces , you can put it in the context of everything else that the whole community has already learned about that organism. You can relate the data to what you already know,” Rusche says. “If you go to a species that hasn’t really been studied and you make a discovery, you have a piece of information in isolation.”

Any tips for bakers and brewers?

Baker’s yeast, Saccharomyces cerevisiae , proofing with sugar and water in a ​40-minute time-lapse animation. Photo: Douglas Levere

Christopher Rupert, a PhD candidate in Rusche’s lab, says one of the neat things about yeast is that these organisms evolved not to help humans make bread and beer, but to survive in their ecological niches.

“A lot of people associate yeast with beer and bread. Yeast ferments — it takes in sugar and spits out alcohol and CO2 — and that’s why we love it so much,” he says. “But what’s interesting is that it is hypothesized that this evolved as a way for yeast to fight other micro-organisms. Yeast has a higher alcohol tolerance, so when it is secreting alcohol, it is killing bacteria around it, so it’s the only one that’s left.”

Rupert’s dissertation deals with the yeast species Candida parapsilosis , which can cause human infections. But he did undergraduate research on S. cerevisiae , and also uses it at home — he’s an avid baker, making dinner rolls, burger buns, buttermilk biscuits and sourdough bread. He seeded his with some baker’s yeast, but it also contains wild yeasts of different species.

“When we used to go into the lab, he would bring stuff in for us to sample,” Rusche says, recalling the days before social distancing. “We would always get all his treats.”

Because yeasts did not evolve specifically to help humans, humans must cater to the needs of yeasts.

For example, S. cerevisiae thrives at temperatures of about 85 degrees Fahrenheit, which is why seasoned bakers often keep their rising dough somewhere warm. Too cold, and the yeast will be slow to grow. Too hot, and it will die.

When it comes to making wine, choosing the right species of yeast can be important, as some can tolerate higher levels of alcohol than others. If your yeast dies before it’s able to consume all of the sugar, your beverage might turn out too sweet, says Walker, who has a peach tree in her yard and makes peach wine.

“If you bake or brew with yeast, you have a living organism. You have to give it time and a nice warm environment,” Rusche says. “Humans domesticated Saccharomyces cerevisiae , but there are so many different species of yeast in the world. Sourdoughs contain a lot of wild yeast, and many of those are not Saccharomyces . They’re such interesting organisms.”

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Bread making - yeast experiment

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26 April 2021

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A community for in-depth discussion of mead; ask questions, post pictures of your mead with recipe, talk about the latest fermentation science... you name it! We have a community Discord! Invite link: https://discord.gg/nRvfFUuzQu

Chef's Experimeads: Evaluation of boiled bread yeast as a nutrient

For quite some time, the conventional wisdom in some circles of the mead world suggested that meadmakers who are unable to source Fermaid O substitute bread yeast that has been briefly boiled (BBY) 1:1. This is by no means universal conventional wisdom, one particular mead luminary likes to quote I believe the founder of Lallemand who apparently said the notion that boiled bread yeast supplies nutrition is science fiction.

While we have always understood that it is a poor substitute, at best, I have had some conversations with a scientist specializing in yeast nutrition at a well known yeast supplier (I prefer not to share identifying information, as my questions on the subject were informal and their answer very speculative so I consider it off the record) that has led me to believe that it is even more poor than conventional wisdom suggests.

The scientist in question speculated that if bread yeast was boiled long enough to break the cell walls, while the quality would be questionable, it would supply minerals and nitrogen derived from amino acids. However, the boiling process would also denature vitamins that are useful to yeast.

Fermaid O by contrast is produced from yeast that has been bred to have high concentrations of specific and desirable nutrient fractions, which are then autolysed using heat and enzymes, then processed through a physical separation process to select specific fractions.

Bread yeast, naturally, is bred to make bread - to maximize co2 production in a short period of time.

The purpose of this experiment is to evaluate the impact of various doings of BBY on fermentation kinetics in the r/mead beginner traditional recipe compared to Fermaid O and DAP only.

A 4.5ish gallon 1.124 SG must was prepared from 15 lbs of Costco Kirkland Signature honey and tap water. Two grams per gallon of US-05, rehydrated in 100F water for 15 minutes was pitched along with 5g/gal of calcium bentonite, not rehydrated. While constantly stirring, this was then divided into six .75 gallon batches. Each batch was oxygenated by supplying 60 seconds of O2 via sintered stone.

Boiled bread yeast for each batch was boiled for 10 minutes. Differing amounts of water from boiling the yeast in each batch led to some variability in the OG of each batch by a couple points, as I neglected to top up each addition to a common volume.

All batches received 3g of DAP at 24 hours post pitch.

Additional organic nutrients for each batch at pitch:

Fermentation kinetics were observed daily by measuring the specific gravity of a vacuum degassed sample from each batch with an Anton Parr digital density meter.

Fermentation Results

This graph visualizes the results. Due to the varying OG of the batches, this graph shows the number of specific gravity points dropped by each batch. The outlier measurements were likely situations where an air bubble was trapped in the device; I wasn't paying particular attention to the trends when I was taking these measurements and should have re-tested.

SG Points Dropped in total:

Needless to say, I was absolutely floored at how perfectly the final results lined up linearly with the amount of BBY added. I was also mildly surprised with the performance of DAP alone.

Sensory Notes

Last week, at 1.5 months post pitch, all batches were fined with kieselsol and chitosan and evaluated once clear by myself, u/StormBeforeDawn and u/CrossPollinator and agreed upon the following observations:

All batches were pleasant and quite drinkable.

Interestingly, the DAP only batch had superior aroma to the rest.

The BBY batches have a subtle (and not at all unpleasant) spicy (think white pepper, not hot peppers) note on the finish.

Each batch will be bottled and evaluated again next week by a wider panel of tasters, and again at 6 months post pitch.

Conclusions

These results seem to indicate that there is some level of nutrient provided by the boiled bread yeast, and perhaps 2.5x BBY as a substitute for Fermaid O may provide similar fermentation security.

This is of course a single data point with a single yeast and a not terribly interesting honey in a single style of mead and should not be taken as gospel. I suspect that the Fermaid O case would demonstrate improved sensory characteristics in a more interesting honey or a style that includes fruit.

I would be thrilled if someone else tried to reproduce my results.

Further Work

I will be shortly starting another trial using only organic sources of nutrients; e.g., Fermaid O and BBY exclusively. Given the results of this experiment, I will have a control (no nutrients), Ferm O, 2xBBY, 2.5xBBY, and 3xBBY.

Updates on past Chef's Experimeads

Whither Magic Powders : These meads ran dryer than I expected and I need to back sweeten. I've had a lot going on and haven't had a chance to get to it. I'm going to try to get that done this weekend and fine with kieselsol/chitosan so I can go ahead and get them into bottles to start distributing for triangle testing.

This Is The Key To Perfectly Proofed Sourdough Bread Every Time

We all love a fresh-baked loaf of sourdough bread, but making bread can be as maddening as it is satisfying — and no part of that process can be more frustrating than proofing. In bread baking, proofing is another name for letting the dough rise, and the timing that goes along with it can be really hard to master because there is no perfect way to measure it. Both over-proofing sourdough and under-proofing it can lead to bad outcomes such as flat loaves, a dense crumb, or too little of a rise in the oven.

In other words, getting the timing right is not only difficult, but also essential. So, for help with this vexing question, Tasting Table asked Nathan Myhrvold, the founder of Modernist Cuisine and lead author of "Modernist Cuisine: The Art and Science of Cooking,"   "Modernist Cuisine at Home,"   "The Photography of Modernist Cuisine,"   "Modernist Bread," and the upcoming "Modernist Pizza," for his advice on the best way to proof sourdough bread.

While most people are used to the idea of proofing at room temperature, Myhrvold has another suggestion, saying "we highly prefer to cold-proof many of our doughs." He explains that cold-proofing slows down the process, so the rise takes anywhere from eight to 18 hours. According to Myhrvold, that's a benefit. "This technique is a useful way to adapt the dough's needs to your own schedule," he explained, adding, "But it's not just about convenience: The long proofing time also improves the dough's flavor."

Cold-proofing gives you more control over timing and flavor

Nathan Myhrvold told us that cold-proofing means having more control over your dough, where "you can vary the time and temperature according to your schedule, needs, and personal tastes." He says it works especially well with bread like sourdough where the rise comes from your starter, but can be used with commercial yeast doughs, too. Best of all, that control also lets you experiment with the flavor of your bread. 

Myhrvold says, "If you prefer very sour-tasting sourdoughs, you'll want to cold-proof as long as possible because longer fermentation produces more lactic and acetic acid. The opposite is true if you prefer a milder flavor." However, if you do opt for a long proof, he recommends adding diastatic malt powder when mixing your dough , which will help keep the yeast fed during the long rise. Myhrvold does warn that cold-proofs are not the best choice for every type of bread. 

Enriched breads, where ingredients like butter and eggs are mixed in , won't rise because the fat in the dough will harden in the cold. He also says that you should pay attention to the temperature in your fridge, advising that while most models run between 33 and 40 degrees Fahrenheit, "if it's possible, adjust the temperature to 4 degrees Celsius/39 degrees Fahrenheit; temperatures any colder than that can slow down yeast fermentation too much." But with those minor concerns out of the way, a cold-proof will be the easiest way to great sourdough.

When Masterpieces Arise from Yeast

Jef boeke and his team create intricate works of art on petri dishes using a palette of yeast paints..

Laura is an assistant editor for The Scientist. She earned her PhD in biomedical sciences from Rush University by studying how circadian rhythms and alcohol affect the gut.

View full profile.

Learn about our editorial policies.

ABOVE: Researchers genetically engineered yeast to produce vibrant hues and employ a technique called “biopointillism” to create intricate works of living art. Aleksandra Wudzinska, Boeke Lab, NYU Langone Health

W hile famous for its role in creating crispy bread and frothy beer, yeast is versatile in numerous applications. Jef Boeke , a geneticist at New York University, and his team use yeast as an artistic medium in their lab. Instead of pens or paintbrushes, these scientists use genetics, genomics, and synthetic biology to transform yeast cultures into vibrant works of art.

The Yeast Art Project arose more than a decade ago as an unexpected offshoot of Boeke’s “Build-a-Genome” course at Johns Hopkins University. Students learned how to build synthetic DNA, and this educational exercise also doubled as a workhorse for a broader project: the creation of a fully synthetic eukaryotic genome of Saccharomyces cerevisiae,  known as Sc2.0 . 1

Tangentially, students used the same techniques to genetically modify yeast to produce beta-carotene, enhancing its nutritional value and transforming its off-white color to shades of yellow and orange. This pigment change inspired a couple of Boeke’s students to explore the artistic side of yeast.

They modified yeast to create living pieces of art on agar canvases using biopointillism; a robot positioned each dot of yeast, or biopixel, onto agar plates. Their first artwork, an homage to Natty Boh, the Baltimore brewery National Bohemian’s mascot, featured three colors and a resolution of 384 biopixels. This artistic direction became an unexpectedly fun side project for Boeke and his team.

By adjusting the number of active genes, “You can change the shade of a certain color by messing around with the combination of promoter and terminator of the gene,” explained Wudzinska. Their initial palette of three colors quickly expanded to nearly 35 colors.

Wudzinska also noted the challenge of making new colors. “We have also played around with the idea of mixing two different types of yeast like yellow and blue to make green,” she added, though these combinations haven’t yielded drastically different results. She found that standalone violacein-producing yeast was more suitable for achieving a signature natural green in recreations of timeless artworks. 

Painting by Pixels

Since Natty Boh, Boeke’s lab drew digital inspiration from celebrated artists like Pablo Picasso and Johannes Vermeer. Recently, Wudzinska turned to artificial intelligence (AI) to explore other art styles like street art graffiti. In this approach, they feed an image into a program that assigns colors and generates a grid of pixel instructions for the Labcyte Echo 550 liquid handler, originally intended for DNA building.

The machine uses sound waves to shoot precisely 2.5 nanoliter droplets up onto an inverted agar plate, creating a paint-by-numbers-like image up to 25,000 biopixels. The yeast-coated plates grow at 30°C for a few days, then researchers refrigerate them to enhance color saturation and prevent overgrowth. Some of the art is as old as three years old, yet the image is recognizable despite the fuzz.

The process of making these yeast canvases requires multiple attempts before it’s just right. “We have the challenge that some strains grow faster than others, so we’ve learned to compensate for that by putting a higher titer of some colors than others,” remarked Boeke. However, Boeke considers the time and effort in crafting these masterpieces a worthwhile endeavor for the yeast of their labors.

Showcasing Yeast Art

As the team incorporated more shades of color and intricate designs, their artwork received recognition. Since 2016, the Yeast Art Project has won science art competitions and has appeared on journal covers. The team also displayed the pieces at the grand opening of the New York Academy of Sciences headquarters in 2023, but curious onlookers’ wandering fingers smudged the ephemeral art. This led Wudzinska to encase the art in epoxy to increase its longevity. 

For Boeke, yeast art represents an exciting fusion of science and art for which he receives funding to support educational outreach. Boeke’s group sends these strains to high schools and undergraduate science programs, encouraging students to learn about genetic modification through hands-on workshops. “A lot of people really respond to this work and say, ‘Oh, it’s so interesting,’ because you can make art with genetically engineered yeast that can make all these beautiful colors,” said Boeke. He expressed his excitement in the evolution of this project and hopes to tackle a 100,000 biopixel image, though he is still mulling over the final design.

• Richardson SM, et al. Design of a synthetic yeast genome . Science . 2017;355(6329):1040-1044. 
• Agmon N, et al. Yeast Golden Gate (yGG) for the efficient assembly of S. cerevisiae transcription units . ACS Synth Biol . 2015;4(7):853-859.
• Mitchell LA, et al. Versatile genetic assembly system (VEGAS) to assemble pathways for expression in S. cerevisiae . Nucleic Acids Res . 2015;43(13):6620-6630. 

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50 Fun Kids Science Experiments

Science doesn’t need to be complicated. These easy science experiments below are awesome for kids! They are visually stimulating, hands-on, and sensory-rich, making them fun to do and perfect for teaching simple science concepts at home or in the classroom.

Top 10 Science Experiments

Click on the titles below for the full supplies list and easy step-by-step instructions. Have fun trying these experiments at home or in the classroom, or even use them for your next science fair project!

Baking Soda Balloon Experiment

Can you make a balloon inflate on its own? Grab a few basic kitchen ingredients and test them out! Try amazing chemistry for kids at your fingertips.

Rainbow In A Jar

Enjoy learning about the basics of color mixing up to the density of liquids with this simple water density experiment . There are even more ways to explore rainbows here with walking water, prisms, and more.

This color-changing magic milk experiment will explode your dish with color. Add dish soap and food coloring to milk for cool chemistry!

Seed Germination Experiment

Not all kids’ science experiments involve chemical reactions. Watch how a seed grows , which provides a window into the amazing field of biology .

Egg Vinegar Experiment

One of our favorite science experiments is a naked egg or rubber egg experiment . Can you make your egg bounce? What happened to the shell?

Dancing Corn

Find out how to make corn dance with this easy experiment. Also, check out our dancing raisins and dancing cranberries.

Grow Crystals

Growing borax crystals is easy and a great way to learn about solutions. You could also grow sugar crystals , eggshell geodes , or salt crystals .

Lava Lamp Experiment

It is great for learning about what happens when you mix oil and water. a homemade lava lamp is a cool science experiment kids will want to do repeatedly!

Skittles Experiment

Who doesn’t like doing science with candy? Try this classic Skittles science experiment and explore why the colors don’t mix when added to water.

Lemon Volcano

Watch your kids’ faces light up, and their eyes widen when you test out cool chemistry with a lemon volcano using common household items, baking soda, and vinegar.

Bonus! Popsicle Stick Catapult

Kid tested, STEM approved! Making a popsicle stick catapult is a fantastic way to dive into hands-on physics and engineering.

Grab the handy Top 10 Science Experiments list here!

Free Science Ideas Guide

Grab this free science experiments challenge calendar and have fun with science right away. Use the clickable links to see how to set up each science project.

Get Started With A Science Fair Project

💡Want to turn one of these fun and easy science experiments into a science fair project? Then, you will want to check out these helpful resources.

• Easy Science Fair Projects
• Science Project Tips From A Teacher
• Science Fair Board Ideas

50 Easy Science Experiments For Kids

Kids’ Science Experiments By Topic

Are you looking for a specific topic? Check out these additional resources below. Each topic includes easy-to-understand information, everyday examples, and additional hands-on activities and experiments.

• Chemistry Experiments
• Physics Experiments
• Chemical Reaction Experiments
• Candy Experiments
• Plant Experiments
• Kitchen Science
• Water Experiments
• Baking Soda Experiments
• States Of Matter Experiments
• Physical Change Experiments
• Chemical Change Experiments
• Surface Tension Experiments
• Capillary Action Experiments
• Weather Science Projects
• Geology Science Projects
• Space Activities
• Simple Machines
• Static Electricity
• Potential and Kinetic Energy
• Gravity Experiments

Science Experiments By Season

• Spring Science
• Summer Science Experiments
• Fall Science Experiments
• Winter Science Experiments

Science Experiments by Age Group

While many experiments can be performed by various age groups, the best science experiments for specific age groups are listed below.

• Science Activities For Toddlers
• Preschool Science Experiments
• Kindergarten Science Experiments
• First Grade Science Projects
• Elementary Science Projects
• Science Projects For 3rd Graders
• Science Experiments For Middle Schoolers

How To Teach Science

Kids are curious and always looking to explore, discover, check out, and experiment to discover why things do what they do, move as they move, or change as they change! My son is now 13, and we started with simple science activities around three years of age with simple baking soda science.

Here are great tips for making science experiments enjoyable at home or in the classroom.

Safety first: Always prioritize safety. Use kid-friendly materials, supervise the experiments, and handle potentially hazardous substances yourself.

Start with simple experiments: Begin with basic experiments (find tons below) that require minimal setup and materials, gradually increasing complexity as kids gain confidence.

Use everyday items: Utilize common household items like vinegar and baking soda , food coloring, or balloons to make the experiments accessible and cost-effective.

Hands-on approach: Encourage kids to actively participate in the experiments rather than just observing. Let them touch, mix, and check out reactions up close.

Make predictions: Ask kids to predict the outcome before starting an experiment. This stimulates critical thinking and introduces the concept of hypothesis and the scientific method.

Record observations: Have a science journal or notebook where kids can record their observations, draw pictures, and write down their thoughts. Learn more about observing in science. We also have many printable science worksheets .

Theme-based experiments: Organize experiments around a theme, such as water , air , magnets , or plants . Even holidays and seasons make fun themes!

Kitchen science : Perform experiments in the kitchen, such as making ice cream using salt and ice or learning about density by layering different liquids.

Create a science lab: Set up a dedicated space for science experiments, and let kids decorate it with science-themed posters and drawings.

Outdoor experiments: Take some experiments outside to explore nature, study bugs, or learn about plants and soil.

DIY science kits: Prepare science experiment kits with labeled containers and ingredients, making it easy for kids to conduct experiments independently. Check out our DIY science list and STEM kits.

Make it a group effort: Group experiments can be more fun, allowing kids to learn together and share their excitement. Most of our science activities are classroom friendly!

Science shows or documentaries: Watch age-appropriate science shows or documentaries to introduce kids to scientific concepts entertainingly. Hello Bill Nye and the Magic Schoolbus! You can also check out National Geographic, the Discovery Channel, and NASA!

Ask open-ended questions: Encourage critical thinking by asking open-ended questions that prompt kids to think deeper about what they are experiencing.

Celebrate successes: Praise kids for their efforts and discoveries, no matter how small, to foster a positive attitude towards science and learning.

What is the Scientific Method for Kids?

The scientific method is a way scientists figure out how things work. First, they ask a question about something they want to know. Then, they research to learn what’s already known about it. After that, they make a prediction called a hypothesis.

Next comes the fun part – they test their hypothesis by doing experiments. They carefully observe what happens during the experiments and write down all the details. Learn more about variables in experiments here.

Once they finish their experiments, they look at the results and decide if their hypothesis is right or wrong. If it’s wrong, they devise a new hypothesis and try again. If it’s right, they share their findings with others. That’s how scientists learn new things and make our world better!

Go ahead and introduce the scientific method and get kids started recording their observations and making conclusions. Read more about the scientific method for kids .

Engineering and STEM Projects For Kids

STEM activities include science, technology, engineering, and mathematics. In addition to our kids’ science experiments, we have lots of fun STEM activities for you to try. Check out these STEM ideas below.

• Building Activities
• Self-Propelling Car Projects
• Engineering Projects For Kids
• What Is Engineering For Kids?
• Lego STEM Ideas
• LEGO Engineering Activities
• STEM Activities For Toddlers
• STEM Worksheets
• Easy STEM Activities For Elementary
• Quick STEM Challenges
• Easy STEM Activities With Paper  

Printable Science Projects For Kids

If you’re looking to grab all of our printable science projects in one convenient place plus exclusive worksheets and bonuses like a STEAM Project pack, our Science Project Pack is what you need! Over 300+ Pages!

• 90+ classic science activities  with journal pages, supply lists, set up and process, and science information.  NEW! Activity-specific observation pages!
• Best science practices posters  and our original science method process folders for extra alternatives!
• Be a Collector activities pack  introduces kids to the world of making collections through the eyes of a scientist. What will they collect first?
• Know the Words Science vocabulary pack  includes flashcards, crosswords, and word searches that illuminate keywords in the experiments!
• My science journal writing prompts  explore what it means to be a scientist!!
• Bonus STEAM Project Pack:  Art meets science with doable projects!
• Bonus Quick Grab Packs for Biology, Earth Science, Chemistry, and Physics

Subscribe to receive a free 5-Day STEM Challenge Guide

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30 Savory Quick Bread Recipes for Fast and Easy Baking

In a hurry? We've got you covered.

Corey Williams is a food writer for MyRecipes and Allrecipes. She has a decade of journalism experience.

Allrecipes Video

Sure, chewy sourdoughs and fluffy focaccias are great in theory—but making them is often an all day affair. When you're short on time, there's nothing like a savory quick bread to whip up on a moment's notice. Pair these loaves, biscuits, scones, muffins, and more with your favorite dinners or enjoy them alone as a snack.

Spicy Cheese Quick Bread

"This is a spicy cheese bread that goes great with grilled meats or a simple salad. It's great sliced thin and lightly toasted too!" —ecolter

Jim's Cheddar Onion Soda Bread

"It's fluffy without being crumbly, has a sturdy crust without being hard, and the cheddar and onion balance perfectly with the butter and sugar. This recipe is divine, and will absolutely be making the rounds through my regular baking schedule." —KristenLouise

Herby Ricotta Biscuits

Allrecipes Magazine

"These herby ricotta biscuits are classic biscuits made savory. A great side dish or brunch item." —Chadwick Boyd

Homemade Flour Tortillas

Dotdash Meredith Food Studios

"This traditional flour tortilla recipe makes soft and delicious homemade tortillas that taste much better than store-bought." —LaDonna

Savory Zucchini Muffins

"A nice change from the traditional sweet zucchini muffin, this recipe utilizes zucchini, onion, garlic, roasted red pepper, and sun-dried tomatoes, resulting in a moist, savory muffin that's perfect at breakfast, lunch, or dinner time!" —ChristineM

Easy and Delicious Crusty Popovers

"I grew up with these buttery popovers served with homemade turkey noodle soup. Very easy to make and tasty. DO NOT open the oven until done!" —Rebecca Cartwright

Amazingly Easy Irish Soda Bread

 WeirdAuntMartha 

"Irish soda bread made with buttermilk and basic pantry ingredients. The buttermilk gives this crusty loaf a good flavor. It's the best Irish soda bread around!" —MP Welty

Quick and Easy Cheese Bread

"This easy bread is excellent with anything from meatloaf, to soups, to chicken. Tastes wonderful, but is pretty crumbly." —Elizabeth Sarah

Savory Onion Bread

"This has become a favorite...as a bread, or smaller portions in a muffin pan." —Retha Van Staden

Chef John's Buttermilk Biscuits

"This deceptively simple buttermilk biscuit recipe can come out a million different ways with some very minor variations on the ingredients and amounts. This one's my favorite — flaky, but not dry; chewy, but not tough; and crisp in just the right spots." —Chef John

Mexican Style Cornbread

"This Mexican-inspired cornbread is made with creamed corn and minced jalapeños for a spicy kick. It's rich and flavorful with a crisp topping of cheese." —Lynn Gibson

Sweet Potato Sage Biscuits

"These savory sweet potato sage biscuits with a touch of honey are buttery, flaky, and dramatically layered." —Chadwick Boyd

Apple, Cheddar, and Rosemary Beer Bread

"Apple chunks, sharp Cheddar cheese, and fresh rosemary are a great savory and sweet combination in this beer bread. It's especially good with soup or chili." —Tammy Lynn

Slow Cooker Parmesan-Garlic Quick Bread

"Easy, and surprising to make inside a slow cooker!" —fabeveryday

Whole Wheat Beer Bread

"This was so good tasting and easy to make. I used Beck’s non-alcohol beer and followed recipe exactly. It is dense with a chewy crust . So good!!" —chris188

Basic Corn Muffins

"A simple but delicious muffin recipe that can easily be dressed up by adding cheese, jalapenos, honey, or anything else." —Doug Matthews

Parmesan Chive Biscuits

"These savory Parmesan chive biscuits can go with nearly any dinner main, or will be a superb addition to the brunch buffet." —Orsi

Red Lobster Cheddar Biscuits

"Red Lobster biscuits are loaded with Cheddar cheese and brushed with seasoned butter in this easy copycat recipe. No kneading is required — just drop the gently mixed batter directly onto a prepared baking sheet and your warm, freshly baked, bite-sized biscuits will be ready to enjoy with dinner in just 15 minutes." —cookingmaniac

Savory Cheddar Zucchini Muffins

"I developed this recipe when I had an abundance of zucchini and wanted a muffin to have with a chicken dinner. These savory muffins are great as a quick breakfast too! They're a hit even with those who think they don't like zucchini!" —Pam Ziegler Lutz

Homemade Arepas

Buckwheat Queen

"Found my new go-to breakfast sandwich bun. You can do so much with it. I added Everything Bagel seasoning to a few of them just to experiment. Yum!" —Patty

Easy Cheese and Garlic Scones

"This is my favorite, very simple, recipe for savory scones. They are wonderful served hot, spread with a little butter, and eaten alongside a steamy hot soup." —Angela Gear

Rosemary-Garlic Beer Bread

"This rosemary beer bread recipe couldn't be easier: You don't have to activate any yeast, there's no rise time, and it comes together shockingly quickly with a homemade shortcut." —Corey Williams

Green Chile Cheese Beer Bread

"This has become my base for all beer bread variants. I still make this version regularly and it turns out nicely." —elriana

Jalapeno Green Onion Ale Corn Bread

"This sweet and spicy corn bread is perfect for a Mexican meal or grilled food." —Karen Moorse

Daddy's Savory Tomato Biscuits

"My father was a man that could take an unstocked kitchen and make a gourmet meal. I watched him make these biscuits when we were out of milk. Just amazing!" —michellej

Mini Parmesan Scones

"These were soo good! I'm not sure what texture I was expecting, but these tasted like biscuits to me. Either way, they were outstanding." —Shantae B

Jalapeno Cheddar Cornbread Muffins

"Loved these! Best corn bread muffins I've ever had. The chunk of mozzarella and jalapeño on top was genius." —Brushjl

"Beer bread is a quick bread to make to accompany any beef dish. The type of beer you use will change the taste. Serve topped with butter or cheese spread." —Jodi Regan

Vickie's Beer Bread

"Love this bread its so easy. I find it tastes better on the second day." —Melissa Costello Adams

fabeveryday

"My boys raved over it and it will for sure be a repeat. For a quick bread recipe, this one is hard to beat." —Tammy Caouette

More Inspiration

• Use Your Stale Bread in These Savory Bread Puddings
• 5 Deliciously Savory Cheese Scone Recipes
• 18 Extra-Easy Beer Bread Recipes

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June 18, 2024

This article has been reviewed according to Science X's editorial process and policies . Editors have highlighted the following attributes while ensuring the content's credibility:

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trusted source

Brazilian scientists develop functional bread that could help prevent asthma

by Julia Moióli, FAPESP

Brazilian researchers have developed functional bread with the potential to prevent asthma, a respiratory disorder responsible for some 350,000 hospitalizations per year in the SUS (Sistema Único de Saúde), the nation's public health care network.

The formulation, for which a patent application has been filed in Brazil (BR1020210266465), is described in an article published in the journal Current Developments in Nutrition . It contains Saccharomyces cerevisiae UFMG A-905, a strain of brewer's yeast with probiotic properties that has been shown to attenuate the symptoms of asthma in mice. Further trials involving human volunteers are still required.

One of the most common diseases in the world, asthma is increasingly frequent and affects some 20 million Brazilians, according to the database maintained by the Ministry of Health (DATASUS). It is characterized mainly by airway inflammation and hyperresponsiveness. Its exact causes are poorly understood, but it is known to be associated with environmental irritants, diet, and gut microbiota, among other factors.

Asthmatic patients can benefit from ingestion of probiotics thanks to the link with gut microbiota. These beneficial bacteria are typically administered on their own or blended with dairy products such as milk, yogurt and kefir, but nothing prevents the use of other vehicles, which is advisable for patients who suffer from lactose intolerance or milk protein allergy.

In this study researchers at the University of São Paulo (USP) included S. cerevisiae UFMG A-905 in naturally fermented bread for the first time. Groups at the State University of Campinas (UNICAMP) and the Federal University of Minas Gerais (UFMG) collaborated on the project.

To assess its potential, the researchers tested and compared three types of bread. The first was fermented with commercial yeast, the second with S. cerevisiae UFMG A-905, and the third with S. cerevisiae UFMG A-905 plus microcapsules containing live S. cerevisiae UFMG A-905.

"We added encapsulated live yeast in order to improve probiotic viability and activity at the high temperature reached during the baking process," said Marcos de Carvalho Borges, last author of the article and a professor in the Department of Clinical Medicine at the Ribeirão Preto Medical School (FMRP-USP). "Microcapsules protect bioactive and probiotic compounds, improving their stability, survival and bioavailability."

Mice with asthma were fed the different types of bread for 27 days. At the end of the experiment, the mice fed S. cerevisiae UFMG A-905 bread displayed less airway inflammation and lower levels of asthma biomarkers (interleukins 5 and 13, or IL5 and IL13, which are proteins secreted by the immune system).

In mice fed the bread containing microencapsulated yeast, airway hyperresponsiveness and levels of IL17A, another biomarker of asthma, were also reduced. These results were similar to those of previous studies, confirming that live S. cerevisiae UFMG A-905 can help prevent asthma.

"We found that both types of bread fermented with S. cerevisiae UFMG A-905 prevented the development of asthma in the mice, which in conjunction with the results of other experiments shows that this yeast has highly consistent effects and appears genuinely capable of combating this respiratory disorder," Borges said.

Next stage: Clinical trial

While acknowledging the limitations of the study, such as not including bread fermented with commercial yeast plus microcapsules and not assessing the survival of S. cerevisiae UFMG A-905 microcapsules after baking, the scientists believe they can now take the next step, which will consist of developing a protocol for a clinical trial to observe the effects of the yeast on human beings.

"The product has significant potential," Borges said. "Bread is a natural food consumed by almost everyone including children. It's easily distributed and has a good half-life on the shelf."

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