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The Crust is the Limit: Bread Blog



In the beginning, we had 3 members and then lost one due to sickness, but we had to keep going and make our amazing bread. The group started on Wednesday with a lab to observe the amount of CO2 bubbles are present using certain types of water solutions and yeast. In our lab, we had the most CO2 production with just plain water so that is what we decided to used in our recipe. Although the tube with 1% sucrose made the most bubbles it didn’t fill up the balloon quite as much as the tube with no sucrose.  Then in the planning stages of the recipe, we did a little research and looked at multiple different recipes from other blogs and baker websites. We found the most common ingredients were flour, sugar, oil, yeast, water, and a pinch of salt, so that is what we used. IMG_1342.JPG

Why those ingredients?

Baggie (1)  

We used the baggie as a mixing ground for all of our ingredients for our dough.

Yeast(¼ tsp)My group used ¼ tsp. Yeast cells grow on simple sugars. As the sugars are broken down, carbon dioxide and alcohol are released into the bread dough, making it rise.

Flour(½ cup)-  Brings the structure in the baking bread, also when mixed with other ingredients it produces gluten.

Sugar(¼ tablespoon)-  Sugar is broken down by the yeast and this creates a gas which makes the bread rise. Not to mention it gives it a very sweet taste.

Salt (a pinch)- Used as a supplement for flavor. Salt helps to tighten the gluten structure and lock in the dough.   

Water  (120 Degrees)-  The water must be at this temperature to activate the yeast, if it is too hot it may kill the yeast.

Oil (¼ tablespoon)-  Oil has a very big role in the texture when oil is added it disables the dough from being too elastic


What is cellular respiration? Why was it not important?


Cellular respiration is processes that take place in the cells of organisms (plants) to convert biochemical energy from nutrients into adenosine triphosphate (ATP), which is then used to power the cell's activities. This process happens in the mitochondria of the cells. Cellular respiration occurs in every living organism and the equation for cellular respiration is Glucose+Oxygen→Carbon Dioxide+Water+ATP. Cellular respiration is not important because in order to make bread the yeast uses alcoholic respiration to create carbon dioxide and alcohol.

Where do plants fall into this process?IMG_1351.JPG

Before flour became its powdered form we get the grocery store it had to start somewhere. It started out as wheat in a field with the hot sun beating down on it and going through a process called photosynthesis. In the process, glucose and oxygen were made from carbon dioxide (that came from humans breathing it out) and water (which came from rain or sprinklers). Although the flour no longer goes through photosynthesis, when it was turned into the powdered form 10% of the glucose is left and passed into the bread.


Anaerobic Respiration VS Aerobic Respiration

There are two types of respiration and those are aerobic, which requires oxygen, and anaerobic, which does not require oxygen. Within anaerobic respiration, there is alcoholic fermentation for plants and lactic acid fermentation for animals and humans. The common cells used to produce Alcohol are yeast. Yeast does not require oxygen or CO2 for respiration or photosynthesis. Yeast breaks down sugar to use for respiration, which produces their energy. Fermentation is the breakdown of a simple, or complex carbohydrate to produce energy and alcohol. This is needed in the break to create CO2 bubbles to make the bread rise and create alcohol to make the bread taste like bread. Lactic acid fermentation happens in our muscle cells when we are exercising feverishly and it makes the muscles very sore. Lactic acid is produced when the muscle tissues release energy for muscle contraction with anaerobic respiration, which is when no oxygen is involved in the release of energy to the muscle cells. IMG_1291 (1).JPG

How is the CO2 cycle involved?

All living things need carbon. The carbon cycle is where plants take in CO2 from the atmosphere, then animals eat the plants to get CO2, and then the animals breathe out CO2 back into the atmosphere, and plants take in CO2 from the animals. Bread making falls into the carbon cycle by the flour in the bread. The flour was once wheat and that wheat made glucose and CO2 and when it was made into the powdered form of flour about 10% of the glucose and CO2 was transferred to us humans by eating the bread with the flour in it. Then we breathed out the CO2 which was put in the atmosphere and taken in by more wheat to start the process all over again.Image-1.jpg


Design Rationale for the Recipe and Reflection

We created the recipe we did because it seemed like the best recipe combination with the items we were given and brought in. We added about a fourth of what regular loaf recipes would call for since we were only making like a small muffin or ¼ of a normal loaf size. We say that the recipe was pretty successful but it was a little bit dry. It might have been a little bit better if it was fresh out of the oven and maybe had some kind of butter spread on it. But overall it tasted like a basic and plain piece of bread. The bread had many bubbles, it was thick, and was very flaky. The bread was also somewhat dense which could have been a result of adding too much oil. Adding the oil was a good addition in terms of keeping some moisture in the bread but adding too much made the bread dense. We did research on ingredients like sugar which makes the dough rise and feeds the yeast through anaerobic alcoholic fermentation or oil which keeps moisture in the bread. We look at other bread recipes that were found on other blogs and compared them to the procedures that Ms. Lawrence gave us. As we compared simple bread recipes to the one Ms. Lawrence started us with we realized that flour, yeast, and water were all the same key ingredients in each recipe. So we used those key ingredients as well as oil, salt, and sugar.




  1. ½ Cups of flour

  2. ½ Tablespoon of yeast

  3. ¼ Tablespoon of sugar

  4. 4 Tablespoons of water

  5. 1 bag



  1. In the bag add ½ tablespoons of yeast, ¼ cup of flour, and ¼ tablespoons of sugar into one bag and shake the bag until everything is thoroughly mixed up.

  2. Heat 4 tablespoons of water to 120 degrees Fahrenheit

  3. Add the 4 tablespoons of water to the bag and stir to combine

  4. Let the mixture set for 10 minutes to activation the yeast

  5. Mix the remaining 1/4 cup of flour into the bag and then take the dough out of the bag

  6. Knead the dough for 1 minute and then roll the dough into a ball

  7. Place the dough ball under the heat lamp and allowed to rise for 30 minutes

  8. Then bake in the oven at 350 degrees Fahrenheit
sophialovesyeast's picture


The Beginning:

Turns out asking your grandma how to make bread actually pays off. We were assigned this project in our honors biology class, and we immediately started to research.  The project was to make bread, and to find out what ingredient makes the fluffiest, most risen bread.

You may think, how does this creative and hands on activity relate back to a high school biology class. Well if you keep reading you will soon find out.


Reflection On Day One:

Ours turned out to be one of the fastest growing ball of bread.  We talked to the group with the second largest ball of bread, group , to find out their procedures.  Our recipe was different from theirs in the way that they didn’t even add olive oil.  Also they used ½ cup of flour while we only used a ¼ two times.  I think the reason our bread was bigger than everyone else's, was that we used olive oil, and salt.  I saw almost no other groups using olive oil.


So we had to follow our teachers basic ingredients, probably so no one made anything too disgusting.  The basic ingredients were flour, sugar, yeast, and warm water.  We did as we were told, but we were given the chance to add our own ingredients.  We researched and found out that salt would add strength to our bread, and it would help our bread hold onto the carbon dioxide made when fermentation occurred.The more carbon dioxide meant the bigger the bread would get, so we new salt was a must.  We also chose to use olive oil to add depth and flavor, it would also not let it dry out as fast, giving it the texture we were looking for.


Although our ball of  bread was one of the largest in the class, it still had room for improvement. Our teacher gave us some advice in that our sugar ratio was a little off.  This being our first day, there was room for error, but the next day we would have to step it up another notch.  Having a correct sugar ratio could potentially mean even more risen bread.  The bread yeast breaks down the starches and sugars, and a product of this breakdown would be carbon dioxide.  Which is a gas that helps the bread rise.

Results Of Day One

0 Minutes: Small, round, doughy

5 Minutes: Darkening, somewhat larger

10 Minutes: Golden on edges, rising more, bigger

15 Minutes: Grew a lot more (largest as of now), darker

20 Minutes: Grew even larger

25 Minutes: Cracking/breaking apart at the top, much larger and widening out

30 Minutes: Risen very high, crisp on the top, air bubbles


Reflection Day Two:

Going into day two we wanted to do everything we did the following day, because the results were so good.  The only thing we did differently today was add more sugar, by a whole teaspoon more.  We did this to try and balance the sugar ratio, because more sugar means more risen bread.  At the start of the heating process the bread didn’t seem to be rising as much as it did the previous day.  But with time it seems to have expanded more.

Results Of Day Two

0 Minutes: Small, round, doughy

5 Minutes: Not much of a difference

10 Minutes: Golden on the edges, rising more and bigger

15 Minutes: Big difference, bread rose almost twice as much

20 Minutes: Larger than any bread at this point, grew a lot

25 Minutes: Even larger and crisping at the top

30 Minutes: Wouldn’t even fit in the pan

Our recipe:

-pinch of salt

-¼ cup of flour (twice)

-¼ teaspoon of yeast

-4 tablespoons of warm water (120 degree F)

-dash of olive oil

-½ teaspoon of sugar (day two we did 1 ½ teaspoons)


Day One Steps:

-Step one  get yourself a ziploc bag or bowl for

mixing all of your ingredients


-Step two add all dry ingredients.  This was the simple, just make sure you don’t get confused between teaspoon and tablespoon, because that will play a major role in the product.



-Step three warm 4 tablespoons of water to 120 degrees, we put it in for 45 seconds in the microwave. The monkey cup is optional but does give it that extra umph, you know what I mean? We shortly found out that this was too long after checking the temperature, so we poured out some of the hot water and added a couple splashes of cold water, to bring the temperature down. You need to make sure your water is not hot, or above 120-130, because it can kill your yeast, and result with terrible bread.  At this point we then added the dash of oil, we ended up adding more oil than we initially thought we would.  We thought the mixture looked too dry, and we wanted a nice consistency.

-Step four mix until it looks like everything is combined enough, at this point in the process we were afraid we didn’t add enough water.  But we just let it sit, and it turned out great. I would not recommend adding more water.

-Step five let sit for 10 minutes


-Step six, after letting your dough sit for 10 minutes you are going to add another ¼ cup of flour.  Than you will mix this all together, but make sure not to over mix.


-Step six knead dough for 1 minute, we found if you cover your hands and the cooking area with a little flour, the dough will not stick to your hands as much, which will make this process easier in general.

-Step seven shape it into a ball and put under a lamp, and we checked every five minutes to see how much it rises under the heat.  We also put our in the very center of the lamps, this may have helped ours get the most heat.  Ours did turn out to be the biggest one at the end, I mean what can I say, we are just good like that.


Why is this happening?

So you may ask, How/why did the bread expand and what's the science behind it? And i have the answer. So the bread used aerobic respiration, more specifically alcohol fermentation. This means that the bread used cellular respiration rather than photosynthesis. This happened as a result of the bread taking in oxygen and sugar being added to the mixture (in this case glucose). The dough then produced carbon dioxide which made the dough rise and water was also produced.

Photosynthesis also played a role in this process.  The flour comes from the plant, wheat, which had to go through photosynthesis. Wheat is then grounded up to make flour, and flour was a key ingredient in our recipe. The formula for Cellular Respiration is this, 6O2+C6H12O6=6H2O+6CO2+ATP.

Cellular respiration takes place in the mitochondria of the cell, and it is very important in the making of bread.

Carbon Cycle

Making bread also affects the carbon cycle, because the sugar activates the yeast and the yeast produces carbon dioxide.  


The Final Product

I guess it’s a good sign if your bread can’t even fit in the muffin tin with everyone else's bread..  Our bread turned out great, it grew more horizontal than vertical.  We  did tie for first place, so our recipe and plan worked out just as we planned it to.  I wish it could have expanded up more, but looking at bread it usually grows both ways.  When we got our bread back it was exploding out of the little muffin tin, and everyone else’s bread wasn’t.  All of our group was in the room when the bread got out of the oven so we were able to test it while it was still hot.  We noticed that it was golden brownish on the outside.  It was cupcake like because it was so fluffy, also partly because it was cooked in a cupcake wrapper.  It was a lot sweeter than we thought it would be, and it had a lot of little air bubbles inside of it, from the carbon dioxide.

biobread123's picture

Background: Cellular Respiration & CO2 Cycle

When making bread you can see cellular respiration in action, but what is cellular respiration? Cellular respiration is the process of the cell turing glucose into a usable energy.  It can be expressed in the chemical equation below:

image credit;

There are two types of cellular respiration: aerobic and anaerobic. Aerobic respiration is the kind that is pictured above; broken down glucose combined with oxygen creates CO2, H2O, and most importantly ATP. ATP, or adenosine triphosphate, is the kind of energy your body uses. Aerobic respiration produces 34 molecules of  ATP.


When you look at bread you see the other kind of respiration: anaerobic. Anaerobic is respiration without oxygen. There are two types of anaerobic respiration, lactic acid fermentation and alcohol fermentation. For the purpose of this lab we’re going to focus on the later, although most organisms go through both processes.


Animals use aerobic respiration and lactic acid fermentation. Plants use aerobic respiration and alcoholic fermentation. The process for aerobic respiration is pretty similar in all organisms; the glucose (whether created by photosynthesis or consumed in food) in broken down in a process called glycolysis which takes place in the cell’s cytoplasm. Then in the mitochondria the glucose combined with oxygen as depicted in the equation above.


Anaerobic respiration in humans happens with lactic acid fermentation, while it produces no ATP it is still very important.. When the cells in your muscles run out of oxygen they anaerobically produce lactic acid so that your body can continue working. If you muscles start to hurt while exercising, that’s lactic acid fermentation


In plants and yeast however they use alcohol fermentation. When they don’t have access to oxygen they produce CO2 and ethanol. This is important in bread making because the CO2 produced by the yeast is what makes the bread fluffy.


The CO2 cycle is the way that carbon dioxide cycles through the atmosphere. There is tons of CO2 in the atmosphere and there are many ways that it gets there.We can see the cycle operating in plants and animals.  Animals when they respirate take in oxygen and release CO2, this CO2 is then taken in plants in order to photosynthesize (turn CO2 and water into glucose and O2). CO2 is also released by animal waste, released in matter broken down by decomposers and emitted whenever fossil fuels are burned.


The carbon cycle is one of the most important environmental processes in our world today which is why it’s dangerous to tamper with it. Scientists believe that the excessive burning of fossil fuels releases too much CO2 in the air, trapping heat in the atmosphere which can cause global climate change.   


Overall you can see the importance of CO2 and respiration within the process of bread making and other places in your everyday life.


Original Recipe and Why We Changed it

When we first started this process we did some research and created a recipe. It consisted of flour, water, sugar, yeast, and salt. In class we were able to test and see how it would work. We started with adding ¼ cup of flour into the bag and combining it with ½ teaspoon salt, ¼ teaspoon yeast and ¼ teaspoon of sugar. Then we added 4 tablespoons of water that was about 128 degrees. Then we let the yeast sit for 10 minutes. After that we added the final ¼ cup of flour and let it rise. In comparison to some of our other peers our bread was not rising as much, why was this? We were able to conclude that we had too much salt in our recipe, while salt can add flavor to the bread it also can stop the yeast from feeding on the sugars making it harder for it to rise. Another issue we ran across was in our process. We definitely could’ve been more careful in how we measured and combined our ingredients. We determined that the next day when we made our final bread using less salt, being more careful with our measurements, and being more careful in the way we combined our ingredients.


Why We Used the Ingredients We Did

Flour: Flour is most commonly made from wheat and serves one main purpose in bread. Raw flour contains gludian and gliadin. When these two ingredients are combined with water they create gluten. Gluten is what makes the bread dough stretchy. Gluten helps trap the CO2 produced by the yeast in the bread. Flour also contains starch which is stored glucose in plants, this is one of the main sources of food for the yeast.

Water: Water is used to create gluten with the flour and to activate the yeast. The water has to be in the 120-130 degree range in order for it to work properly. If the water is too hot the yeast will die, if the water is too cool the yeast won’t activate.  

Yeast; Yeast is probably the most important and complex part of the bread making process. The yeast once activated by the water feeds off the sugar in flour (the addition of cane sugar or honey can give the yeast more food) and begins the anaerobic respiration process of alcohol fermentation. The yeast takes in the glucose and turns it into ethanol and most importantly, carbon dioxide. The carbon dioxide produced by the yeast is released and trapped. This gives bread it’s fluffy and airy qualities.

Sugar: The addition of sugar (or any natural sweetener) can provide additional food for your yeast which can cause it to rise more giving you a fluffier bread. Although, too much sugar can kill your yeast and if you use artificial sweeteners it won’t provide food for your yeast so it’s not recommended.  

Salt; Salt provides a better flavor in and out of your bread, if you put some salt on the bread before you bake it can create a nicer crust. But, if you add too much it can prevent the yeast form feeding.

Oil: Oil helps to keep the bread from growing stale after a short period of time and like the salt it can enhance the flavor.

Recipe Reflection

We as a group would like to think that our bread was overall quite successful. It was fluffy with air bubbles and rose a fair bit. Looking back on the changes we made I think that made our bread a lot better than if we had gone with our original recipe. We also have no doubt that there are certainly more improvements we could’ve made. Our bread certainly had potential to be fluffier and maybe with more of a crust to it. With unpredictable and for the most part unchangeable factors such as the environment, the brands we used, the exact temperature of the water, etc there is no true way to tell how successful our recipe would be on another day. It could work even better or it could end up worse. But, looking at the time we had and after thoroughly examining our results we can proudly say we did a pretty good job.




  • ½ cup of all purpose flour

  • ¼ tsp yeast

  • ¼ tsp sugar

  • ¼ tsp kosher salt

  • ⅛  tsp olive oil

  • 4 tbsp of water

  • Additional pinch of salt  



  1. In your plastic bag combine ¼ cup of flour ¼ tsp of yeast, ¼ tsp of sugar, and the ¼ tsp of salt.

  2. Heat up 4 tbsp of water until it’s 120-130 degrees and gradually add to dry ingredients while stirring.

  3. Wait about 10 minutes for the yeast to activate (you will see bubbles forming)

  4. Then add the additional ¼ cup of flour to bag.

  5. On a lightly floured surface knead your dough for about 1 minute.

  6. Take your ball of dough and allow it to rise for about 30 minutes on a warm surface. (We used heat lamps but if you heat your oven and place the dough on top it will work just as well.)

  1. When your dough has risen lightly coat it in the olive oil and add the final pinch of salt.

  1. Bake for 30-40 minutes.

emma marquita and lilly period 3's picture
emma marquita a...


By: Marquita, Lilly, and Emma


Hello!! Are you interested in a scrumptious bread recipe filled with lots of flavor?


My friends and I wanted to test some new recipes, so we decided to delve into some baking. Lilly told me about her grandmother’s legendary whole wheat chocolate chip bread. Then my other friend Emma suggested we make our own bread recipe.

Our steps:

For our bread We first mixed together ¼ teaspoon of yeast as well as ¼ cup of flour in a plastic bag. We then heated 4 tablespoons of water to 120-130 degrees (F) in a microwave for approximately 1 minute so that the yeast can activate at the proper temperature. When the water was ready we slowly poured it into the baggie, and stirred it with the rest of the ingredients. After this we waited ten minutes for the yeast to activate, before adding the rest ¼ cup of flour to our baggie. After we added one tablespoon of sugar as food for the yeast. We mixed our baggie, and then added a small pinch of salt to tighten the glucose, and strengthen the bread by holding in the co2 during alcoholic fermentation and slowing the process of the fermentation. We slowly poured half a tablespoon of canola oil into the bag as well to help hold the gases in the bread in order to help the bread rise. My gals and i mixed the bag once more before moving onto the next step.


WE prepared a wide sheet of wax paper and laid it onto our table. After we sprinkled the lightest amount of flour evenly onto our wax paper. We gently pulled the bread mixture from the baggie and rolled it onto the flour. My friends and i molded the bread into a rounded ball shape, and added the necessary amount of flour when it was too soggy. We placed the wax paper with the bread ball still on it under a heat lamp for 30 minutes. This allowed the dough to rise.


  • We added the ¼ tsp of yeast to our bread mixture because yeast undergoes alcoholic fermentation. The product of the fermentation is co2 and alcohol. The co2 is what causes the bread to rise by creating air pockets in the bread.


  • We added the ¼ cup of flour to our bread mixture because flour provides gluten for the yeast to rise and therefore provides and strong dough structure.


  • We added the ¼ tbsp of warm water to the bread mixture to help create an appropriate temperature for the yeast to activate. The water also helps with the consistency of the bread and the production of gluten.



  • We put the water in the microwave because we needed the water to reach a temperature of at least 120-130 degrees (F)

  • The water must be at this temperature for the yeast to activate and start the alcoholic fermentation.

  • We added 1 tbsp of sugar to our bread mixture for the yeast to undergo the alcoholic fermentation. The yeast breaks down the sugar into co2 and water. by adding the sugar, it will help make the bread rise.




  • We rolled the dough into a ball to then put it under the light. Under the light the yeast undergoes alcoholic fermentation. The yeast uses the ingredients to produce co2 which is what causes the dough to rise.


Our recipe was successful!!

The texture of our bread was firm, not too dense and not too soft. We observed that the bread was porous with varied sizes of pores. The color was a light brown, with a toasted surface. The independent variable that we changed in our recipe from the first attempt was the addition of oil and salt. The salt took away from the sweetness, while the oil lightened the texture of our bread.

jackjackdavina's picture


Jack Fleming, Davina Ahlawat, Jack Szczuka


I first made this recipe with my grandmother when I was seven. I have been making it with my grandmother ever since then for me and my family on thanksgiving. It has become a tradition that my family and I love to do each year, and now I would like to share this recipe with you!




¼ teaspoon yeast

Pinch of salt

4 teaspoons orange juice  

⅛ tbsp orange peel (grated)      

3 teaspoons sugar                                                 

¾ cup flour

¼ tbsp shortening

⅛ egg

2 tbsp milk



1 tsp cinnamon

⅙ cup sugar

Dash of water




We chose these ingredients because the yeast will help rise the bread, and the orange juice will speed up the time needed for the bread to rise. They all including milk add to the taste, but milk and yeast also add to the tenderness of the bread. Orange juice also adds some sugar to the bread. The shortening adds taste and freshness. The orange zest adds flavor to the bread. Last but not least, the salt flavors the bread and strengthens the bread.

If  you want to make this treat with a bigger or smaller servings you can always use these ratios to do so:

Sugar 1 tbsp: 3/4 tbsp Flour

Pinch of salt: 3/4 tbsp Flour  

Sugar 1 tbsp: ¼ teaspoon yeast  



Above is the hot water with dissolved yeast inside.           In the picture we have mixed all the ingredients in this

                                                                                      step. I did it in a bag but a bowl will work as well.   

Step 1) Dissolve the yeast in hot water. In a plastic bag, combine milk, orange juice, sugar, shortening, orange peel, and salt. Add 6.4 tbsp of flour, yeast mixture, an eighth of an egg, and mix well. Add enough extra flour to form a soft, kneadable dough.



  In the first two pictures it shows the surface you want     The image above shows how you want to place the

 to kneading on/ how to do it.                                           Image under a warm place so that it can rise.

Step 2) Knead on floured surface until smooth and elastic. Let rise in warm place until doubled in size.



You are going to want to check the dough every so often and then mold it into rectangles.

Step 3) Punch dough down. Cover and let rest for 10 minutes. Then roll each portion into rectangles.



 The first image above shows the sugar      The second image shows to how     The third/last image shows you

and the cinnamon filling with the water.      to put the filling into the bread.     how to roll the dough in the jelly roll                                  


Step 4) For filling, combine sugar and cinnamon. Sprinkle as much as needed over rectangles. Sprinkle each with a dash of water. Roll up jelly roll style, and seal the edges. Place in a pan, and cover to let rise until doubled in size again.

Step 5)  Bake at 375 for 15 minutes or until golden brown. Remove and let cool. Eat and enjoy!

The Science Behind It All


Cellular Respiration

Cellular respiration is a cell in an organism using 6 02 molecules C6H1206 molecules to create 6 CO2, 6 H2O, and an ATP for energy. This takes place in the mitochondria of a cell, and is not important in making bread because yeast uses alcoholic fermentation for energy, there are no cells taking in oxygen in the bread. Although, wheat uses photosynthesis and cellular respiration, and wheat is contained within flour before bread is made.


Anaerobic vs aerobic respiration

Yeast uses anaerobic respiration to create energy , while humans use aerobic respiration to create energy. This is important for bread making because bread uses anaerobic respiration to create carbon dioxide bubbles in bread.


Bread-making & the Carbon Cycle

Bread creates CO2, which contains carbon and releases it into the atmosphere. This CO2 is taken in by plants for photosynthesis.


After tasting our bread, we realized our modifications to make the bread less wet were too extreme, and the bread was dry and floury. The inside was airy and crumbly, but the outside was tough and flavorless. We did not add enough orange juice/orange peel to get a substantial orange flavor, and because the shape was not conducive to the tin we had to put it in, the cinnamon was uneven in the halved dough. I believe our original ratios would have been closer to the ideal bread, but the cooking conditions certainly did not help.

breadblog's picture

Bread Blog


In our biology class, we are making bread. Considering none of us are true “bakers” and have never attempted to make bread from scratch before, we weren’t too sure about how our product would turn out. The main point of this bread lab was for us to better understand how fermentation, photosynthesis and cellular respiration takes place when making bread.




First, in a ziploc baggie mix together ¼ teaspoon yeast, and ¼ cup of flour and, 1 tbsp of sugar and ½ tsp of salt

Then we heated 4 tablespoons of water to 120 °F - 130 °F and let the water heat for 1 minute in the microwave.

Slowly add the 4 tablespoons of heated water to the baggie and stir all of the ingredients up.

After everything is stirred up let the mixture set for 10 minutes, to activate yeast.



Next mix in an additional 1/4 cup of flour in the baggie.



Knead dough for 1 minute.


Take dough out of the bag and roll it into a ball.

Place dough ball under heat lamp and allow it to rise for 30 minutes


(One with the orange writing on the tape)


After heated for 30 minutes, bake in the oven.


Our bread-making ingredients consisted of;

¼ teaspoon yeast

¼ cup of flour

1 tbsp of sugar

½ teaspoon of salt

2.5 tablespoons of water

¼ cup of flour (additional at the end)


Why did we choose these specific ingredients? Well, a couple givens are flour, sugar and water. We knew that these were necessary for making bread. Although some ingredients such as sugar and yeast, were two things that our group had not known were necessary for making bread. After looking over our teachers recipe, observing our classmates attempts, researching online and trying the experiment once (and failing) we collected data and information and decided specific amounts we wanted to use per each ingredient. As mentioned earlier, our first bread-making experience was a failure. So, to increase the overall quality of our bread the second time we ensured that we added sugar (which we did not do the first time), and also added salt. Want to find out why these components are a key to success when making bread? Then keep reading, in the next section, The SCIENCE of Bread Making!


The SCIENCE of Bread Making!

The first day was just a practice day to see what works and does not work when making bread. Therefore, it was a failure. At first, we were missing some key components like sugar. Sugar is a crucial part in this lab because in order to make bread, the yeast needs to be activated. In order for yeast to be activated, it needs to feed off of glucose, which is sugar. In the bread making process yeast goes through cellular respiration, which is undertaken in the mitochondria. The equation for cellular respiration is C6H12O6 + 6O2  →  6H2O + 6CO2 + ATP. Originally, the bread respires aerobically, or with oxygen- this process helps create CO2 and assists in helping the bread rise. Then, as the oxygen runs out, much like humans when, for example, exercising aerobically (running), anaerobic respiration begins.  

You might be wondering, how does bread making tie in with the Carbon Cycle? Well, The carbon cycle is the cycle of carbon through the atmosphere, ground, plants, and animals. Bread has yeast in it, and yeast needs Carbon Dioxide for it to activate and grow. The carbon comes from the air and the yeast absorbs and uses it. The carbon is made in a way it can be used when hot water, yeast, and sugar are together.


Our final Product

(Top left)


In the end, our recipe was not 100% successful because our bread was a bit too watery and salty, although it was still a success because we learned what we could do better next time and gained a better understanding on the science aspect part. What could we do different? In the future, we could do more additional research on ratios of the ingredients and also know exactly what ingredients we need. And also we could use less salt. Overall, the experiment was a great learning experience and something we all enjoyed doing!


DuckBread's picture

Chocolate Yeast Bread


Baking Team:

Head Baker - Jess M

Photographer - Adam T

Blog Writer - Ethan K




Cellular Respiration


Yeast bread is made when yeast is mixed with other ingredients to make dough, and the yeast goes through alcoholic fermentation. Alcoholic fermentation is a process where glucose is turned into ethanol (alcohol), carbon dioxide, and energy. The process of alcoholic fermentation takes place in the cytoplasm of yeast cells. Having yeast which goes performs alcoholic fermentation is important in baking bread because it turns the dough from a rough dense mass into a smooth extensible dough, which means that the dough can be stretched, and that when it is cooked it will have the texture that we like our bread to have.


Anaerobic Respiration VS Aerobic Respiration


Yeast cells perform alcoholic fermentation and respiration. They perform cellular respiration because it is what creates ATP and all organisms need to do it. Alcoholic fermentation is anaerobic, and it is what happens when there is no oxygen and cellular respiration cannot be performed. Humans cells also go through cellular respiration, but instead of alcoholic fermentation, our cells go through lactic acid fermentation. This causes fatigue in our muscles, making us stop what we are doing in order to get some oxygen. This is important for making bread because it means that yeast is the only cell that can be used to make bread.


CO2 Cycle


Yeast respires and releases carbon dioxide. In nature, yeast is found in plants, which take in carbon dioxide and perform photosynthesis. Photosynthesis then releases oxygen and all living things take it in and go through cellular respiration.





⅛ cup of warm water

½ cup of milk

½ egg

1 ½ tablespoons of brown sugar

1 ½ cups of flour

1 tablespoon of white sugar

½ teaspoon of salt

¾ teaspoon of active dry yeast

1 tablespoon of margarine

Chocolate chips




  1. Place ingredients in a mixing bowl/ bag.

  2. Mix ingredients

  3. When the ingredients are mixed together, take out the dough and knead it for about ten minutes.

  4. When you are five minutes in, start mixing in chocolate chips

  5. Roll dough into the shape of a bread

  6. Place in a pan

  7. Add chocolate chips on the top for decoration

  8. Place under a light to activate the yeast

  9. Bake bread in the oven for about two hours

  10. Enjoy




We chose this bread recipe because we wanted a nice bread that also tasted sweet, so that it could be eaten with breakfast, as a snack, or maybe as a dessert. To make this happen, we took a generic bread recipe and added more sugar, cinnamon, and chocolate chips. When eating, we found that the chocolate did not mix well with jam, but adding butter did taste good.



The bread came out very well. The bread tasted a bit dry, which tasted good with butter, however it did not taste like it was meant to have chocolate mixed in it. If we were to make another loaf, I think it would be wise for us to either change up the bread recipe to make it more moist and sweet, or we should remove the chocolate chips and add an ingredient that is less sweet.

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Preparing for the experiment: Balloon lab

In order to begin to understand the process of how yeast interacts with different amounts of sugar we completed a alcohol fermentation lab. To set up the lab we added different amounts of sugar to each test tube, it was as follows:IMG_0741.JPG


Test tube #1- No sugar

Test tube #2- ½ tsp of sugar

Test tube #3- 1 tsp of sugar

Test tube #4- 2 tsp of sugar


After we finished adding all the different amounts of sugar to each test tube then we added 10 mL of 120 degree water to each of the tubes, it is very important that the water is at this temperature so that it is hot enough to activate the yeast, but not so hot that it kills the yeast. Following the addition of water we added ⅛ tsp of yeast to each tube and covered the opening of the tube with a balloon, after this we shook the tubes to dissolve the yeast. The balloon will help us measure the amount of carbon dioxide. Through this procedure we continued to measure two things; the amount of air in the balloon and the height of the carbon dioxide bubbles.IMG_0751.JPG


After 10 minutes- Test tube #2 had both the most air and the most carbon bubbles (2cm) and test tube #4 had the least bubbles and air (.5cm)


In the end of our experiment test tube #2 still had the most air and bubbles, now at 4cm and test tube #4 still had the least of both remaining at a height of .5cm and almost no air in the balloon.


Day #2: Research

Before we could actually make our bread we needed to figure out a recipe that would give us optimal carbon dioxide production and rising of the bread. We did this by researching the different things in bread that help make it rise such as gluten. Through this research we were able to determine what ingredients we should add to our bread to increase how much it would rise. For our bread we decided to add sugar because as proven in the balloon lab adding a certain amount of sugar helps to increase carbon dioxide. We also decided to add olive oil because while we were researching we found that olive oil reacts with the gluten and helps to increase the rising properties of bread.


Day #3: Practice Round IMG_0805.JPG

The purpose of this day was to test out our recipe and discover any flaws it may have, so that we could adjust the recipe before the actual baking day. We started with the steps of the original dough recipe; we added the ¼ cup of flour and ¼ tsp of yeast to our plastic bag in addition to this we chose to add sugar (1 tsp)  and salt (a pinch for flavor).  


After the completion of the dry ingredients we needed to heat our water to add. As mentioned before we needed to make sure the water was at an optimal temperature to activate our yeast (120-130 degrees). Once our water was properly heated we added 4 tablespoons of the hot water to our dry ingredients, we also chose to add olive oil to further activate our yeast (½ tsp), we then mixed all the ingredients in our bag.


Kneading our bread proved to be a challenge; it was very sticky and we couldn't get it to come together even with the addition of extra flour. Our bread also didn’t rise as well as we had hoped. Through this first round we learned that we needed to add more flour to our bread to make it much less sticky and easier to knead. We also decided we were going to add more olive oil to hopefully increase the amount that our bread would rise.   

Day #4: Final Dough

Today was the final day and we needed to make sure that this time our bread would rise properly and that we would be able to kneed it this time without it being overly sticky, like our experimental bread the previous day. We made many changes to hopefully make this change occur, these included:


  • Adding ½ tablespoon of sugar instead of 1 teaspoon of sugar

  • We added another ½ teaspoon of olive oil with the remaining flour as well as still adding olive oil with the water

  • Instead of just adding  ¼ a cup of flour the second time around we also added just an additional ⅛ cup

  • Before we started kneading the bread we made sure to thoroughly cover the parchment paper in flour to reduce to sticking of the dough, we also added flour to to sydney’s hands and the dough


This time when we added the dry ingredients, water, and oil to our bag and let it sit for 10 minutes there was much better carbon dioxide production than the previous day, we think this has to do with the addition of extra sugar to our dry ingredients. This is because the yeast feeds on the  sugar and this creates carbon dioxide so and increase in sugar makes for an increase in carbon.   


We also made sure that when we were kneading our dough that we first covered the parchment paper in flour so it wouldn’t stick to the paper, and we continued to add flour until the dough was at a good consistency and we could roll it into a ball. The addition of the extra flour really helped reduce the amount of “stickiness”  in our dough and made it much easier to knead and eventually form a ball.


We checked the progress of our bread rising every 5 minutes and each time we checked it the bread continued to rise. The first time we checked it the bread was at 2.5 cm and that was at 10 minutes, then at 15 minutes the bread had rose to 3.5 cm. For the last 15 minutes our bread remained at 5 cm. This proved that the changes we made the first day greatly improved the outcome of our bread and helped the production of carbon dioxide massively. IMG_0829.JPG

Day #5: Finished Bread!!

Our bread really rose to the occasion! With the changes, we made our bread rose a ton indicating lots of carbon dioxide production. When you looked at our bread from the outside it was a nice golden brown color on the top and it had clearly rose above the top of the muffin tin. We split our bread in half to see the inside of the bread and we saw a ton of bubbles and it was very light and airy. The taste of our bread was pretty bland and tasted like flour and yeast, we compromised the taste for increased carbon dioxide production and rising properties.IMG_0837.JPGIMG_0834.JPG


The reason our bread rose substantially and made so much carbon dioxide is because the second time around we added more flour to our dough. Once the yeast is activated it comes in contact with the flour and feeds on the sugars that are in it, this releases carbon dioxide. We also added more sugar which also gets broken down by the yeast and produces more carbon dioxide, all of this carbon dioxide made our bread rose.

Breaking it down: The science of bread

The equation for cellular respiration is C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP. The process of cellular respiration occurs in the mitochondria. The mitochondria is the powerhouse of the cell; makes the energy. Cellular respiration is important for bread making because yeast is what goes through the process. Yeast goes through anaerobic fermentation which also helps produce beer and happens without the presence of oxygen, while aerobic respiration requires oxygen to be present. During the bread production, yeast starts to respire, creating carbon dioxide and water to help the bread rise. After the oxygen runs out, anaerobic respiration begins.

Plants are important to cellular respiration because they allow for the process of glycolysis which is the breakdown of glucose. This process occurs in the cytoplasm of plants, and when the glucose is broken down the yeast can feed on the sugars that come from it, and carbon dioxide is in turn produced. During this lab the wheat in the flour was the main peice responsible for this taking place.


Yeast and humans have more similar characteristics than opposing characteristics.

Yeast vs Humans: Yeast undergoes cellular respiration by starting with aerobic respiration. After the oxygen runs out, anaerobic respiration occurs and the alcohol is evaporated in the high temperatures in the oven. Humans: Humans undergo aerobic respiration because they breathe in oxygen and aerobic respiration is with oxygen. Humans also go through anaerobic respiration because humans go through lactic acid fermentation.

Bread making falls into the carbon cycle due to the fact that the yeast respires and released carbon dioxide into the atmosphere. In the environment, the yeast can be found in plants. The plants take in the carbon dioxide and goes through photosynthesis. This causes it to release oxygen and all living things take it in. Temperature is related to amount of CO2 produced by yeast, this being higher temperatures will result in more production of CO2 and the cycle keeps going.

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  • First we added ¼ cup of flour

  • We also added a bit of flour to the dough as we were kneading it to make it not stick to our hands as much and so the dough would stick together better

  • We then added 4 tablespoons of heated water

  • We also added ¼ teaspoon of yeast

  • Then we added ½ teaspoon of sugar

  • We also added ⅛ teaspoon of salt

  • We then added one teaspoon of vegetable oil

  • Then after we mixed it all together and let it sit for 10 mins..

  • We then added another ¼ cup of flour

Design rationale for recipe

We added ¼ cup of flour and 4 tablespoons of heated water in order to form glucose, the water held the purpose to “wake” the ¼ tablespoons of yeast. We also added ½ teaspoons of sugar for the yeast to eat as they use anaerobic respiration to produce the CO2 bubbles, and thus cause the bread to rise with the help of the stretchy glucose.  The purpose of the fat and salt was to help make our bread last longer, however we used a small amount of salt in order to not inhibit the yeast.  Finally, we let the dough sit for 10 minutes in order to let the yeast activate, then we added ¼ more cup of flour to help set the dough.


Day 1 conclusion

This was our first test at it, so we weren’t sure exactly as what ingredients would make the “perfect bread”. For our next test we will be adding less water to make it less runny (3 tablespoons instead of 4). We will also be adding more sugar (2 teaspoons) so the yeast can have a bit more “food” to eat. We won’t be adding salt to our bread to see if it might rise a bit faster.


Day 2 conclusion

Today is Day 2 of our testing. We are going to apply the changes that we made and see what happens to the bread. So far, our bread has not risen very much. It has stood the same height and width. In 20 mins, it grew a little bit in width.



Overall, the forming of the bread was successful, but the taste of the bread was not. Our ingredient choice was correct for the most part, considering the bread actually rose. There were air bubbles within the bread as well. The bread was very dense. We should have added less sugar so that the yeast were not so overworked.  We probably should have used salt or spices for a better taste to the bread.


Cellular respiration

C6h12o6 + o2 -> co2 + h20 + ATP

Sugar + oxygen -> carbon dioxide + Adenosine Triphosphate

Cellular respiration takes place in the mitochondria.

Cellular respiration is used by all organisms to convert glucose into ATP

Cellular Respiration is not important in bread making because, contrary to popular belief, yeast does not use cellular respiration.  Yeast uses alcoholic fermentation which is a form of anaerobic respiration.

Plants cells have mitochondria along with their chloroplasts, and cellular respiration takes place in the mitochondria.

Photosynthesis is important to bread making because the wheat that is in bread uses photosynthesis to grow.  


Anaerobic Respiration vs Aerobic Respiration

Aerobic respiration is a process of CR that uses oxygen, however Anaerobic does not. Yeast uses anaerobic respiration because oxygen is not available to them, whereas humans use both (because oxygen is sometimes not in large enough quantities for Aerobic respiration; ex: working out).

This is important to bread making because we want to be mindful that yeast only use Anaerobic respiration to generate energy/CO2.



Fermentation relates to bread making because yeast goes through alcoholic fermentation. Yeast obtains all of its energy from alcoholic fermentation, which is a process that converts glucose into energy and has CO2 as one of its products.


CO2 Cycle

Bread fits into the carbon cycle by expiring CO2 from the yeast and into the atmosphere, it is a contributor to the cycle rather than removing from it.


Anaerobic Respiration vs Aerobic Respiration

Yeast vs Humans (5)

Why is this important for bread making? (5)

Yeast undergoes a form of anaerobic respiration (respiration without oxygen) called alcoholic fermentation. There is no oxygen because the bread has no holes to allow it into the bread. This the CO2 produced during alcoholic fermentation has no holes to escape the bread, the bread rises. Humans undergo aerobic respiration (respiration with oxygen). This is how obtain energy


In order from left to right, here are the steps:


^ Day 1 pictures.   Day 2 pictures (changes)/almost end result. V





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