Since the chemistry is similar for all of these experiments I thought I would discuss it in general and then add more detail where required.
Yeast: a group of single-celled fungi but specifically for baking there is a yeast called Brewer's Yeast which is used as a leaven-er. Carbon dioxide and alcohol are the main components involved in the metabolism of yeast using sugar as its third agent. The chemical equation: C6H12O6 -----> 2C2H5OH + 2CO2. The yeast requires sugar as a very important player in order to successfully react and first consumes the single sugars of the reaction and then moves onto the double-unit molecules of sugar. When the yeast is ready to be used it must be added to warm water (not too hot and not too cold) or else it will not react. This is a very important understanding when dealing with yeast. Literally, not a reaction will occur without the proper temperature of water. Such a finicky thing! Dry yeast is still somewhat of a mystery but it can be assumed that when the yeast cells are dried that some amount of the carbohydrates are left and concentrated inside. When the warm water is added some of these carbohydrates burst out of their cells to achieve balance and serve as the energy for the metabolisms to occur. If the temperature of the water is too cool it will prevent the cells from reconstituting while the higher temperatures damage the cells. Yeast serves as a leavening agent as it releases carbon dioxide which is captured in the dough creating pockets of air allowing for a light and fluffy texture. Proofing the yeast simply means that you are allowing the yeast to react with the water and the sugars. Before starting the main recipe you proof the yeast by letting it begin its reaction in water prior to adding any ingredients. Allowing it to sit for 10-15 minutes ensures that the yeast is reactive and that it is going to do its job. As the dough progresses there is a period of kneading which is very important in the creation of delicious dough. One of the most important things that takes place during the kneading process is the development of gluten. As the flour that makes up the dough is moistened and stirred, the gluten begins to form and also gains strength as the dough is subjected to the kneading process. Gluten is the binding agent within the dough, allowing the loaf to take on a cohesive texture that will allow the substance to not fall apart during baking. The presence of the gluten also sets the stage for another good reason to knead bread dough as the gluten is acting as a binding agent, it is also helping to create small air pockets of bubbles in the dough. This is very important, as these bubbles are necessary to allow for the formation of small pockets of carbon dioxide as the dough is rising. The carbon dioxide is created by the interaction of the yeast with the other ingredients in the recipe as explained above. By filling the small air pockets in the structure of the dough, the bread has a chance to rise and become supple enough to result in a loaf of bread that is light, flavorful, and airy.
A. Title: Basic French Bread Experiment #1
(white flour gluten structure)
B. Reagents:
2 1/2 Cups Water
2 Tbsp Yeast
1 Tbsp Salt
6-8 Cups Unbleached White Flour
Corn Meal for Baking Sheets
C. Outline Procedure:
1. In a mixing bowl, add water and yeast. Allow mixture to sit for ten minutes.
2. Add 3 Cups of Flour. Mix for 5 minutes.
3. Let mixture sit for 1 hour.
4. Add salt and enough of the remaining flour to pull mixture into a soft dough.
5. Once a soft dough is formed, knead for 5 minutes.
6. Place dough in a lightly greased bowl and coat dough well to prevent it from drying out while rising.
7. Allow dough to double in size.
8. Once dough has doubled in size, split dough into two equal masses. Shape into a traditional French loaf.
9. Place newly shaped loaves on a baking sheet that has corn meal sprinkled on it.
10. Bake in a 425 degree oven until the internal temperature reads 210 degrees.
11. Place bread on a cooling rack and allow to cool.
D. Actual Procedure and Observations:
This recipe went rather smoothly without any hiccups. We ommitted the extending rising time but other than that the recipe was followed exactly. It was easy to add the flour and to take over with kneading. We didn't let the dough rise in the bowl with oil which I think caused a bit of drying out but it didn't sit for all too long so I don't think our final product was effected by that. We did forget to add the salt at the right time so we ended up adding it when we were kneading the dough. We just added a little at a time to prevent salt pockets but it worked out just fine and I am so glad that we added it because we forgot to add it to the wheat and it was not so good!
E. Discussion and Conclusion:
Our yeast was allowed to proof for about 10 minutes as instructed by the recipe, this obviously included the water. The flour was added and mixed until very smooth and combined which took about 5 minutes. Due to time limitations we were unable to let the dough sit for an hour and only gave it about 5 minutes. In an ideal circumstance we would have allowed it to rise allowing a strong gluten network to form but this was my favorite bread with or without the extra rising/kneading time. Very chewy and moist.
A. Title: Basic French Bread Experiment #2
(whole wheat flour gluten structure)
B. Reagents:
2 1/2 Cups Water
2 Tbsp Yeast
1 Tbsp Salt
6-8 Cups Whole Wheat Flour
Corn Meal for baking sheets
C. Procedure Outline:
1. In a mixing bowl, add water and yeast. Allow mixture to sit for ten minutes.
2. Add 3 cups of flour. Mix for 5 minutes.
3. Let mixture sit for 1 hour.
4. Add salt and enough of the remaining flour to pull mixture into a soft dough.
5. Once a soft dough is formed, knead for 5 minutes.
6. Place dough in a lightly greased bowl and coat dough well to prevent it from drying out while rising.
7. Allow to double in size.
8. Once dough has doubled in size, split dough into two equal masses. Shape into a traditional French loaf.
9. Place newly shaped loaves on a baking sheet that has corn meal sprinkled on it.
10. Bake in a 425 degree oven until the internal temperature reads 210 degrees.
11. Place bread on a cooling rack and allow to cool.
D. Actual Procedure and Observations:
This bread was identical to the white french with the minor exception of the flour. We had the whole grains that we finely blended in the blender to form a rich flour. We let the yeast rise just like in the previous recipe and then added the remaining ingredients...minus the salt. Completely forgot to add the salt and it made a huge difference. It was more difficult to knead this dough as the batter stuck to our hands and when it dried it dried like a paste that didn't want to let go! It was so messy. We however knew that something was missing to our dough as it was not stretchy and bouncy as the first dough. It was very crumbly and gritty in texture. I had made wheat bread in the past and thought it was strange that the recipe called for white flour as well but today it all became apparent. The wheat flour needs something more added to it to make it all stick together and for the gluten network to form. So to keep our bread from falling apart we used about 1 cup of white flour and it was almost better than the white bread (if only we had remembered to add the salt!).
E. Discussion and Conclusion:
The only thing that I would have changed with this recipe is that I would have added something to make the wheat pull together more. During the end of class discussion it was made clear to us that in order to make a true whole wheat flour bread some type of agent must be added to allow a great gluten network to be formed. This could be by means of xanthum gum which is a polysaccharide, derived from the bacterial coat of Xanthomonas campestris, used as a food additive as a food thickening agent and a stabilizer to prevent ingredients from separating. The proportions that we were given in class explained that for every cup of whole wheat flour 1 Tbsp of wheat gluten should be added to allow the dough to come together. Everything else worked exactly how the white bread above worked as the explanation above describes with the yeast and the gluten network.
A. Title: Basic Loaf Pan White Bread Experiment #1
(milk scalded)
B. Reagents:
2 tsp Yeast
2 Tbsp Sugar
1 Cup Cooled Scalded Milk
4 Tbsp Melted Butter
1 tsp Salt
3-4 Cups Flour
C. Procedure Outline:
1. In a bowl combine yeast, sugar and milk.
2. Let stand until foamy, about 10 minutes.
3. Add the flour, a little at a time, mixing until the mass pulls together into a soft dough.
4. Continue to mix until the dough is soft and satiny but still firm, 4 to 5 minutes.
5. Dust with additional flour, if necessary, to keep the dough from sticking.
6. Place in an oiled bowl and coat well to prevent dough from drying out while proofing.
7. Once the dough has doubled in size, shape it as desired.
8. Bake in a 350 degree oven for approximately 30 minutes or until internal temperature reaches 190 degrees.
D. Actual Procedure and Observations:
The only thing in this recipe that differs much from the other was the addition of the scalded milk. We didn't actually do the scalding ourselves which was nice since we had so much to do today but we did discuss the process of scalding milk. You have to be very careful that the milk not burn on the bottom of the pan and to also be careful that if this does happen to not scrape the burnt milk and incorporate it in the liquid. We allowed the milk, yeast and sugar to sit together and have the yeast react with its partners. (See the discussion below to talk about the importance of scalding the milk here. There is a reason we did it!) All other ingredients were added after the yeast had its alone time. As before the recipe called for allowing the dough to double in size which we almost were able to do as this dough was started mid-way through the class but not quite long enough. It took a while to bake this dough as our loaf was quite thick and required a much longer cooking time.
E. Discussion and Conclusion:
Why scald the milk? Such a funny thing to do before adding in all of the other ingredients that would mask the flavor of the scalded milk, right? I did some research on the matter and while taste is one reason why scalded milk is done in recipes there is one more very important reason. There is an enzyme in milk, protease, which inhibits gluten formation. Pasteurization doesn't reach temperatures sufficient to destroy it so scalding the milk is required. Protease is an enemy of yeast and if the protease isn't disabled, you can end up with a weak sticky dough which collapses like an over-proofed loaf. If you're baking a bread rich in dairy and sugar, scalding and skimming off the skin will result in a lighter, more tender bread. Which was true in our case. This bread was very light and chewy. I think once again, if we would have had more time to allow the bread to proof it could have been a bit lighter but compared to the second loaf it was much lighter.
A. Title: Basic Loaf Pan White Bread Experiment #2
(without scalded milk)
B. Reagents:
2 tsp Yeast
2 Tbsp Sugar
1 Cup Milk
4 Tbsp Melted Butter
1 tsp Salt
3-4 Cups Flour
C. Procedure Outline:
1. In a bowl combine yeast, sugar and milk.
2. Let stand until foamy about 10 minutes.
3. Add the flour a little at a time, mixing until the mass pulls together into a soft dough.
4. Continue to mix until the dough is soft and satiny but still firm, 4-5 minutes.
5. Dust with additional flour if necessary, to keep the dough from sticking.
6. Place in an oiled bowl and coat well to prevent dough from drying out while proofing.
7. Once the dough has doubled in size, shape it as desired.
8. Bake in a 350 degree oven for approximately 30 minutes or until internal temperature reaches 190 degrees.
D. Actual Procedure and Observations:
I hate to defer to the above recipe but it was exactly the same as the recipe above without having the milk scalded. Everything else worked exactly the same in this recipe. The dough was a little different to work with as it was so easy to knead and smoothest in texture of all of our other bread but it didn't rise as much. The final product also turned out to be much smoother, smaller and darkest in color than the other recipes.
E. Discussion and Conclusion:
The difference between the two loaves can be explained by the milk. The first recipe the dough was lighter, fluffier and also less smooth. It ended up looking a little rough. However it was also larger in size than this loaf and upon the taste test it was much more chewy and light. This recipe was a bit tough and small although very smooth and pretty. I was surprised to see how much of a difference the two breads had just because of the scalded milk having lost the protease which allows the yeast to do its job. Chemistry and food are amazing. In the photo you can see the two loaves side by side and the recipe with the scalded milk shows a much larger loaf.
A. Title: Irish Soda Bread Experiment #1
(with baking soda)
B. Reagents:
2-2 1/2 Cups Flour
1 tsp Baking Soda
1 tsp Salt
1 Cup Buttermilk
C. Procedure Outline:
1. Preheat oven to 425 degrees.
2. Combine all dry ingredients and whisk together.
3. Add the buttermilk to form a sticky dough. Place on a floured work surface and gently knead.
4. Shape into a round, and place onto a prepared baking sheet. Cut a cross into the top of the bread.
5. Bake for approximately 45 minutes or until golden brown.
D. Actual Procedure and Observations:
This recipe called for buttermilk which we did not have so we made our own (which is a very handy skill to have when you are in the middle of the recipe and realize you don't have buttermilk!). We simply took the milk and added about 1 Tbsp of vinegar, allowed it to sit for about 8 minutes and we were ready to go. This recipe is vastly different from the aforementioned recipes as there was no yeast involved at all. I reminded me of baking a cake as the dry ingredients are generally all mixed together as well as the yet and then they are all slowly combined to each other forming the batter. Once all ingredients were added together the dough was created and it was much more difficult to knead than the yeast doughs. It was much tougher and as you can see in the picture it was very dense and did not rise all that much. The end result of the dough tasted very much like that of a biscuit in texture and flavor. The loaf was a bit larger than the following loaf when both were finished. We were not able to get an after shot of the bread as we were scrambling to get the bread finished before the end of class. This bread was much smaller than the following recipe.
E. Discussion and Conclusion:
Since there was not any yeast called for in this recipe we were dependent upon another chemical reaction to take place to allow for the rising of the dough creating a bread and not simply a cracker. This became an acid-base reaction. With the acidity of the faux butter milk and the base of the soda our bread was able to rise. Baking soda can by used as the main leavening agent if the batter is already acidic enough to react with it and create carbon dioxide, which it was due to the acidity of the buttermilk. The baking soda-buttermilk ratio provided the leavening action of four times its volume of baking powder, which has the acid and alkaline components.
A. Title: Irish Soda Bread Experiment #2
(with baking powder)
B. Reagents:
2-2 1/2 Cups Flour
1 tsp Baking Powder
1 tsp Salt
1 Cup Buttermilk
C. Outline Procedure:
1. Preheat oven to 425 degrees.
2. Combine all dry ingredients and whisk together.
3. Add the buttermilk to form a sticky dough. Place on a floured work surface and gently knead.
4. Shape into a round and place onto a prepared baking sheet. Cut a cross into the top of the bread.
5. Bake for approximately 45 minutes or until golden brown.
D. Actual Procedure and Observations:
This recipe was exact to the recipe above, even down to the making of the buttermilk. The only difference was that of the replacement of the baking soda for baking powder. The doughs were very similar in the making up until the end when the final dough here was a bit smaller in size than the previous. It also had a bit more of a yellow appearance to it.
E. Discussion and Conclusion:
Baking powder has baking soda in it as well as an acid in the form of salt crystals that dissolve in water. There is also a dry starch present that is added to prevent the premature reactions from occuring in humid air and thereby diluting the powder. Most baking powders are double-acting which basically means that they act once when they are first added to the mixture releasing air bubbles and then again during the baking process when the air bubbles grown in size offering a airy and light texture. This dough is also an acid-base reaction with the salt playing a roll as the acid with an additional player of the buttermilk once again serving as the acid. The base in the reaction is the baking soda. Comparing the tastes and textures of all breads I must say that I prefer the yeast breads much more than I do these last two. Both have a taste similar to that of biscuits but I am a regular bread kind of girl. My husband however much preferred these last two. He's a biscuits and grits kind of guy!
This gives a whole new perspective on take and bake!
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