AP 2- Food

AP Food Teacher: Adam Baking bread

5/20/16

Objective: Purpose of the experiment is to see how effective are leavening agents when compared to one another.

Hypothesis: I believe that the sourdough starter will be more effective than the other leavening materials due to its natural yeast. The sourdough will have a more sour taste because of the fermentation.

Material List: Sourdough: ● ● ● ● ●

¾ starter 3 ½ tablespoon salt 4 cups water Bread flour 10 cups flour

Yeast: ● ● ● ●

3 cups lukewarm water 7 ½ cups flour 1 tablespoon salt 1 ½ tablespoon yeast

Chemical: ● ● ● ● ●

3 ½ cups flour 1 tablespoon sugar 1 tablespoon baking soda 1 tablespoon salt 1 ½ cups buttermilk

Control Group: ​ Commercial Yeast Bread

Ingredient

Calculations

Revised Amount

3 Cups Water

3/1 x 2/7

6/7

6.5­7.5 Cups All­Purpose Flour

13/7 x 2/7

26/49

1 Tablespoon Salt

1/1 x 2/7

2/7

Experimental Group: ​ Baking Soda

Ingredient

Calculations

Revised Amount

3 ½ cup of all purpose flour

None Needed

3 ½ cup of all purpose flour

1 teaspoon sugar

None Needed

1 teaspoon sugar

1 teaspoon salt

None Needed

1 teaspoon salt

1 teaspoon baking soda

None Needed

1 teaspoon baking soda

1 ½ ­2 cups of buttermilk

None Needed

1 ½ ­2 cups of buttermilk

Experimental group 2: ​ Sourdough Starter

Ingredient

10 cups flour

Calculations 10/2

Revised Amount 5 cups of flour

4 cups water

4/2

2 cups of water

3­5 teaspoons of salt

5/2

2 ½ teaspoon salt

¾ starter

¾ /2

⅜ Cups of starter

Variable

Control Group

Experimental Group 1

Experimental Group 2

Flour type

Bread flour

Bread flour

Bread flour

Dough rise time

​ 2 hours

15 min

2 hours

Oven 450 temperature

450 first 15 min

400 for 20 min

400­450

Bake time

35 min

20­30 min

40­60 min

Dough amount

331.25 grams

331.25

331.25

Other

The taste was slightly sweet

The taste was salty but sweet

The taste was salty and the smallest bit sour

Procedures:

Yeast Bread 1. Place all ingredients within a bowl and begin mixing

2. Allow the dough to rise by covering it and allowing it to refrigerate for up to seven days 3. Place more flour on the dough then take ¼ to ⅓ of the dough 4. Re­adjust the dough into a ball and let it set 5.

Place the dough on a piece of parchment that is slightly greased

6. Let the dough rise at room temperature 7.

Cut the bread into 3 pieces

8. Bake the bread up to 30 min 9. Take the bread out

Sourdough 1. Feed starter everyday for about a week 2. Ferment starter and mix it in with the rest of the ingredients 3. Knead the starter to circular shape 4. Divide the loaves and place them in the oven 5. Heat oven to 400­450 degrees and let it bake for 2 hours 6. Take out the oven and enjoy

Chemical Leavening Agent Bread 1. Place all dry ingredients such as flour in the bowl, then place dough inside 2. Claw at the top of the dough softly with a fork 3. Roll the dough into a ball and place it on tray 4. Heat oven 5. Place dough into oven and let it bake at 400­450 degrees

Control And Experimental Group To start to explain the difference between control and experimental we have to know what that is. Control is a part of the experiment that you would use as a base to compare with the result of an experiment, you do not change the control. Now for experimental it is the opposite of the control, the experimental part of the experiment is the part that you change to be able to see the result. The control for this baking experiment was the yeast bread, it is the bread that everyone uses to bake, it is the basics of the experiment. And for the experiment we had used two different kinds of bread, sourdough, and baking soda, these breads were the experimental breads as they

are not used as much in baking. Below the images of the breads is a description of their different variables and how that lead to the final results.

Pictures

Yeast Bread The unique variable used in yeast bread was the amount of water that we added compared to the rest of the breads. We added more water to have a more open texture, a more wheaty or grainy flavor, and a crispier outer crust. Not only this but this bread required the least amount of time to bake and had less ingredients.

Sourdough Bread The unique variable for the starter is it’s fermentation period or how long that it had sat out of the fridge. We let the sourdough starter to sit out for a period of three days which allowed activity such as growth and bubbling to occur which resulted in the sour taste of the bread.

Baking Soda

And lastly for the baking soda bread it had one unique variable, it was the only bread that had any dairy inside of it. Because the buttermilk was inside of the dough it caused the acidity of the milk to react with the baking soda that helped to make the dough rise the most because of the carbonation.

Analysis: For my analysis I received enough data to have finally come to a conclusion. But before I speak of my conclusion I will talk about the process that I had to go through in order to understand the experiment as well as my hypothesis. Originally the chemical bread group or baking soda bread’s dough was 2 inches tall before we placed it in the oven, then after it was taken out of the oven the size had increased to 5 inches. The chemical leavening agent was the baking soda which reacted off of the buttermilk inside the bread. Buttermilk is an acidic base which means it was able to cause a reaction and rise having a pH of 4.8. Now for the control group or yeast bread dough, it was originally 0.5 inches but when put into the oven and allowed to set the size had

increased to 2 inches. And lastly the sourdough group, the dough was originally 1.75 inches and had increased to 2.5 inches, the yeast within the sourdough is called a biological leavening due to its natural ability to make things rise. Now the reasons as to why the bread rose to these sizes was due to the amount of sugars inside the dough or in the case of the chemical bread the size of the reaction. Depending on the amount of sugar that is available within the dough yeast will feed on it and either give off small amounts of carbon dioxide or large amounts which in turn allows the bread to rise. I had originally believed that due to the sourdough starter having natural forms of both sugar and yeast it might have provided more than the other doughs. I was incorrect about my hypothesis, it turns out that the baking soda had more of a reaction than any of the other dough with the yeast and sugar. Now each piece of bread had its own taste that was unique, the starter tasted slightly sour but salty, the chemical tasted sweet, and the yeast had a combination of sweet and salty, the textures of the bread seemed the same to me. The sourdough was smoother on the outer crust but was slightly rough, the baking soda and the yeast bread were actually quite similar, they both had rigid outer crust with clumpy and sticky bread inside.

I also have included a graph above that explains the size change between the bread, and the charts explain the ingredients and measurements included to make the bread.

Conclusion​ :​ My hypothesis when compared to the results was incorrect, the sourdough

starter’s natural yeast did not make the bread rise any higher than I originally believed. That being said in my opinion the sourdough starter had the best taste out of all the batches of bread.

Work Cited

Baking Soda Image: AP.BakingSodaBread.(2016) Sourdough Bread Image: AP.SourDoughBread.(2016) Yeast Bread Image: AP.YeastBread.(2016)