Rise & Shine

What makes dough rise? When you combine ingredients to make bread, the dough appears to, magically, double in size! How does this happen? Separated, these ingredients aren't very exciting. When combined (with the addition of heat), they transform to create a soft, fluffy, delicious loaf of bread. Yum!

According to the Law of Conservation of Mass, matter can be neither created nor destroyed. In other words, the mass of an object or, in this case, the collection of objects, never changes, no matter how the parts are rearranged ("Conservation of Mass"). Chemical reactions take place and transform the ingredients. In a bread recipe, the active ingredient is the leavening agent. The leavening agent is what makes your dough expand and 'rise'.

In our FOOD course, we have been learning about the science of food. I never really thought of food as science before, but it is. Think about it...growing food is Biology, and cooking food is Chemistry. The main focus of this action project was to analyze the effects leavening agents and proportions have in different bread recipes. This was a group action project, and each group baked from different recipes. I was in the Control Group and our leavening agent was yeast.

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QUESTION

How do different leavening agents affect the outcome of a bread recipe?

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HYPOTHESIS

If different leavening agents and ingredient proportions are used across five bread recipes, then each batch of dough will have different chemical reactions, resulting in varying rises, tastes, and textures.

In this experiment, a total of 5 different bread recipes were baked and analyzed - my group was in charge of baking the control recipe using yeast. A control group is a baseline measure. The control group is the same as the experimental group being examined, except it does not receive the same manipulation the experimental group receives. In this experiment, the control was a basic yeast bread recipe. Each of the breads in the experimental groups either had a chemical leavening agent (baking soda) or varying sourdough starter amounts and/or preparations.

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MATERIALS + PROCEDURE

MATERIALS:

Water

Flour

Salt 

Yeast

PROCEDURE:

1. First, we mixed all of the gathered ingredients in a large mixing bowl at about 105°F. We mixed them until we got a rough dough.
2. Then, leaving it in the bowl, we covered the dough in plastic wrap.
3. For 2 hours in room temperature, we let the dough rise. Then we refrigerated it for at least 2 hours, or for up to about 7 days.
4. When it was ready, we sprinkled the top of the dough with flour, which made it easier to grab a hunk. We greased our hands, and pulled off about 1/4 to 1/3 of the dough.
5. After that, the sticky dough was plopped onto a floured work surface, and then rounded into a ball.
6. The height, width, and length of the dough ball was measured and recorded.
7. We then placed it onto a piece of parchment and sifted a light coating of flour over the top.
8. We let the loaf warm to room temperature and rise for about 60 minutes or longer.
9. Then the oven was preheated to 450°F while the loaf rested. 
10. When it was ready to bake, we took a sharp knife and cut the bread twice about a ½ inch deep. It was in the shape of an X mark, and was used as an opening to release air.
11. We placed the bread in the oven and let it bake for 35 minutes. In the end, it ended up in the oven for an hour because we, accidentally, turned off the oven without noticing.
12. The bread was removed from the oven and cooled on a rack.
13. The height, width, and length were, once again, measured and recorded.

RECIPES:

Yeast (Control)
Baking Soda (Experimental #1)
Homemade Sourdough (Experimental #2)
Commercial Sourdough (Experimental #3)
Dennis’ Sourdough (Experimental #4)

YEAST (Control) 

Based on the output of this recipe, we calculated that one loaf would equal 1/3 of each ingredient. 

Ingredient	Calculations	Revised Amount
3 Cups Water	3 / 3 = 1 cup	1 cup
6 ½ - 7 ½  Cups All-Purpose Flour	7 ½ / 3 = 2 ½  cups	2 ½ cups
1 Tablespoon Salt	1 tbsp = 3 teaspoons / 3 = 1 tsp	1 teaspoon
1 ½ Tablespoons Yeast	1 ½ tbsp = 4 ½ teaspoons / 3 = 1 ½ tsp	1 ½ teaspoons

BAKING SODA (Experimental #1)

Ingredient	Calculations
3 ½ cup all-purpose flour, plus extra for dusting	N/A
1 teaspoon sugar	N/A
1 teaspoon baking soda	N/A
1 teaspoon salt	N/A
1 ½ – 2 cups buttermilk	N/A

• Preheat oven to 450 F.
• Place flour, sugar, baking soda, and salt into a large bowl and whisk together.
• Make a well in the center and pour in most of the buttermilk, leaving about ¼ cup in the measuring cup. Using a fork, or one hand with your fingers outstretched like a claw, bring the flour and liquid together, adding more buttermilk, if necessary. Don’t knead the mixture, or it will become heavy. The dough should be soft, but not too wet and sticky.
• When the dough comes together, turn it onto a floured work surface and bring it together a little more. Pat the dough into a roundabout 1½ inches thick and cut a deep cross in it. Place on a baking sheet.
• Bake for 15 minutes. Turn down the heat to 400° and bake for 20-30 minutes more. When done, the loaf will sound slightly hollow when tapped on the bottom and be golden in color. One way to check if your bread is done is to use a thermometer. Cook until temperature in center reaches 195-200 degrees.

HOMEMADE SOURDOUGH (Experimental #2)

Ingredient	Calculations	Revised Amount
10 cups flour	10 / 3 = 3 ⅓	3 ⅓ cups flour
4 to 4 ½ cups of water	4 / 3 | 9 / 2 * ⅓ = 1 ½	4 / 3 to 1 ½ cups of water
3 ½ teaspoons of salt	7 / 2 * ⅓ = 7 ⅙	1 ⅙ teaspoons of salt
¾ cup starter	¾ / 3 = ¼	¼ cup starter

• First, you must make the starter for this bread. You mix 1 cup of flour and ½ cup of water into a bowl, and after this you cover it with a cheesecloth. Everyday for a week you take half of the dough and put it in a separate jar, you then replace the missing dough with another cup of flour and another ½ cup of water.
• When you are ready to make the dough you will be baking bring out your starter, more flour, salt, and water.
• Take out ¼ cup of starter and put it in a pereate bowl.
• Add 3 ⅓ cups of flour to the bowl.
• Add 1 ½ cups of water to the bowl.
• Mix well.
• Let it rest and ferment for 15- 60 minutes.
• Add 1 1/16 or a teaspoon of salt.
• Knead well for 10-15 minutes.
• Check to see if the dough is kneaded enough by doing a windowpane test.
• Make the dough into a loaf.
• Set the oven to 500 degrees for less than an hour
• Place your loaf of bread inside of the oven for 1-3 hours at 400 degrees.
• Ideally your loaf should be 195 degrees when fully cooked.

COMMERCIAL SOURDOUGH (Experimental #3)

Ingredient	Calculations	Revised Amount
1/3 cup sourdough starter	N/A
1 scant tablespoon salt	N/A
1 - 1 1/2 cup water	N/A
3 1/3 cup white flour	N/A

• Mix the sourdough starter, flour, and salt together.
• Add 1 cup water and then more as needed to make a moist bread dough.
• Knead the dough until it passes the “window pane test" (about 20 minutes): a small piece of dough will stretch between 4 fingers, without breaking, thin enough to allow light to pass through.
• Shape the dough into a loaf. 
• Place it in a pan, proofing basket, or on a board. 
• Cover the dough lightly with a towel and allow the dough to rise for 4-24 hours.
• Slice an X shape in the top of the loaf with a very sharp knife or razor blade.
• Bake at 400°F for 30-60 minutes, depending on the size of the loaf, until the internal temperature reaches 210°F (use a meat thermometer inserted into the bottom or side of the loaf). 
• Cool before slicing.

DENNIS’ SOURDOUGH (Experimental #4)

Ingredient	Calculations	Revised Amount
1 tablespoon active sourdough starter	1 / 2 =	½ tablespoon
75 grams (½ cup) all-purpose flour or bread flour	½ / 2 =	¼ cup
75 grams (⅓ cup) water	⅓ / 2 =	⅙ cup
1 tablespoon salt	½ =	½ tablespoon
525 grams (2 ½ cups) water	2 ½ / 2 =	1 ½ cups
700 grams (5 ½ cups) all-purpose flour or bread flour	5 ½ / 2 =	2 ¾ cups

• Make sure your sourdough culture is active.
• Make the leaven (overnight).
• Test that the leaven is ready.
• Dissolve the salt.
• Mix the leaven and water.
• Add the flour.
• Rest the dough (30 minutes, or up to 4 hours).
• Mix in the salt.
• Begin folding the dough (2 1/2 hours).
• Let the dough rise undisturbed (30 to 60 minutes).
• Prepare 2 bread proofing baskets, colanders, or mixing bowls.
• Shape the loaves.
• Transfer to the proofing baskets.
• Let the dough rise (3 to 4 hours, or overnight in the fridge).
• Heat the oven to 500°F.
• Transfer the loaves to the Dutch ovens.
• Score the top of the loaf.
• Bake the loaves for 20 minutes.
• Reduce the oven temperature to 450°F and bake another 10 minutes.
• Remove the lids and continue baking 15 to 25 minutes.
• Bake another 15 to 25 minutes.
• Cool the loaves completely.

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VARIABLES

Variable	Control Group	Exp. Group 1	Exp. Group 2	Exp. Group 3	Exp. Group 4
Dough rise time	60 minutes	No rise time	15 - 60 minutes	4 - 24 hours	4 hours
Oven temp.	450 F	450 F	400 F	400 F	450 F
Bake time	25 - 35 minutes	45 minutes	1 - 3 hours	30 - 60 minutes	55 minutes
Salt	1 tsp		1⅙ tsp		½ tbsp

The most significant difference between variables is the length of the rise time versus the amount of sodium used in the recipe. Experimental Group #4 has a rise time of about 4 hours. This is because Experimental Group #4 has a larger proportion of salt than the other groups. Salt slows down the fermentation process, which is what consumes the sugars and creates gas causing the dough to rise. As far as variable similarities are concerned, groups with an oven temperature of 450F have bake times around 45 - 55 minutes.

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OBSERVATIONS 

Observation	Control Group	Exp. Group 1	Exp. Group 2	Exp. Group 3	Exp. Group 4
Height	2 ½ inches	3 ½ inches	3 inches	1 inch	6 ½ inches
Smell	Fresh bread smell	Cornbread smell	Slightly tangy smell	Strong tangy smell	Fresh sourdough bread smell
Appearance (holes, airiness)	Medium to large air pockets; thick crunchy crust	Dense; no air pockets; flaky crust	Large air pockets; thin crust	Medium to large air pockets; softer crust	Some air pockets; risen, but not fully baked; crisp crust
Texture	Firm	Soft	Medium soft	Soft	Soft/raw
Other	Dark crust	Golden crust	Light crust	Light to golden crust	Golden to dark crust

2018.YeastBread.SN

2018.BakingSodaBread.ExperimentalGroup1

2018.HomemadeSourdoughBread.GR

2018.CommercialSourdoughBread.ExperimentalGroup3

2018.Dennis'SourdoughBread.BD

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TOTAL DAILY NUTRIENT VALUES

FLOUR

Calories

¼ = ¼ = ¼x = 250 = 1,000

100 x ¼ ¼

Carbohydrates

¼ = 2½ = ¼x = 55 = 220g
22g x ¼ ¼

Fat

¼ = 2½ = ¼x = 0g = 0g

0g x ¼   ¼

Protein

¼ = 2½ = ¼x = 7½g = 30g

3g x ¼ ¼

YEAST

Calories

1 = 1½ = 1x = 31½ = 31.5

21 x 1 1

Carbohydrates

1 = 1½ = 1x = 4½g = 4½g

3g x 1 1

Fat

1 = 1½ = 1x = 0g = 0g

0g x 1  1

Protein

1 = 1½ = 1x = 0g = 0g

0g x 1 1

SALT

Calories

¼ = 1 = ¼x = 0 = 0g

0 x ¼ . ¼

Carbohydrates

¼ = 1 = ¼x = 0g = 0g

0g x ¼ ¼

Fat

¼ = 1 = ¼x = 0g = 0g
0g x ¼ ¼

Protein

¼ = 1 = ¼x = 0g = 0g

0g x ¼ ¼

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DAILY PERCENTAGE

Calories
1,000 = 50%
31.5 = 1.57%
0 = 0%

Total: 51.57%

Carbohydrates
220 = 11%
4.5 = 0.22%
0 = 0%

Total: 11.22%

Fat
0 = 0%
0 = 0%
0 = 0%

Total: 0%

Protein
30 = 1.5%
0 = 0%
0 = 0%
Total: 1.5%

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ANALYSIS

 Google Sheets Graph - SN

A leavening agent is a baking ingredient that produces a porous structure within dough or batter. Leavening agents include air, steam, yeast, baking powder, and baking soda. The two types of leavening agents are: biological and chemical. 

Upon observation and analysis, my hypothesis was confirmed. Yeast metabolizes the sugars in a bread recipe, producing carbon dioxide, which causes the dough to rise. In this experiment, I used a biological leavening agent (yeast) in my bread. Leavening is achieved through the process of fermentation. Fermentation is a metabolic process that consumes sugar in the absence of oxygen, releasing carbon dioxide gas ("Science of Fermentation"). This gas is what causes the dough to rise, or expand, giving the finished product that porous/air bubble appearance. Before rising, the yeast dough was one inch high. After 60 minutes, the dough rose two and a half inches.

Chemical leavening agents are compounds that release gases when they react with moisture or heat. Most chemical leavening agents are a combination of an acid and a salt of bicarbonate (baking soda). Baking soda is a base that reacts when it comes into contact with acids, like buttermilk, yogurt, or vinegar. Like yeast, this reaction also produces carbon dioxide in the form of bubbles, causing the dough to rise ("3 Types of Leavening Agents").

The initial pH of a dough should be somewhere between 4.0 to 6.0. If the pH is higher or lower than this range, the yeast will be less active - causing it not to rise. As a dough ferments, the pH drops because of acid production. A fresh made dough will have a pH above 6. The pH will drop during fermentation due to the formation of lactic and acetic acid ("Science of Bread").

The addition of salt in a bread recipe helps the loaf to hold on to carbon dioxide that is formed during fermentation. However, salt slows down fermentation activity in dough. In experimental bread loaf #3, there was no rise recorded. This was most likely due to the addition of salt early in the recipe. 

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CONCLUSION

In conclusion, bread making is a chemistry experiment. It is a delicate balance between proportions, leavening agents, pH, temperature, humidity, and time. If you alter any of these variables, the results could be significant. 

Chemical reactions, like the ones found in bread, occur in many other baking recipes, as well. Cookie recipes, for example, don’t need leavening agents - instead, their existing ingredients just need to be activated by heat. Moisture is one of the ingredients that gets activated. As it evaporates, the steam gets trapped and tries to release itself, creating air bubbles.

In addition to knowing the reactions that take place in recipes, it is also important to know how food will affect you after you eat it. Macro and micro-nutrients help keep our bodies in stable, working condition. Too much or too little of something can have negative consequences, so keeping track of daily nutritional intake is vital. Different ingredients have different effects, not just on the food...but on your body, as well.  

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CITATIONS
“Conservation of Mass.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 2018, kids.britannica.com/students/article/conservation-of-mass/599570.

“No-Knead Crusty White Bread Recipe | King Arthur Flour.” King Arthur Flour - Try It Once, Trust It Always, www.kingarthurflour.com/recipes/no-knead-crusty-white-bread-recipe.

“Science of Bread: Bread Science 101.” Exploratorium, www.exploratorium.edu/cooking/bread/bread_science.html.

“The 3 Types of Leavening Agents In Baking and How They Work.” The Spruce Eats, TheSpruceEats, www.thespruceeats.com/main-types-of-leavening-agents-and-how-they-work-4125705.

“The Science of Fermentation.” Bake | Baking News, 19 June 2015, www.bakemag.com/Trends/Bread-Winners/The-science-of-fermentation.aspx.