Yeast on the Rise

Hooray, it’s finally (Foodie) Friday!

Since the last Foodie Friday post on sourdough microbes a couple weeks ago, I have been thinking about making my own bread again.

Because I am not taking care of a sourdough starter currently, I made a loaf of bread using Baker’s yeast, or Saccharomyces cerevisiae. S. cerevisiae is commonly used as a fermentation agent in bread making and the production of carbon dioxide gas during metabolism by yeast contribute to the leavening and flavor and texture of bread.

In the grocery store, we often see active dry yeast. Active dry yeast consists of granules of intact yeast cells encapsulated within a thick dry layer of dead cells and lyophilized growth medium. Therefore, to determine whether the yeast is indeed still active it must be “proofed.” Proofing yeast involves dissolving the yeast in water (or another liquid) and waiting for the yeast inside the capsules to begin metabolism. After about 10 minutes, the mixture should form a foam layer (from released carbon dioxide gas) at the top proving that the yeast is alive and active. When I was proofing yeast last weekend, I substituted buttermilk for regular milk. This created a fascinating proofing process in which gas bubbles had to escape from the thicker-than-normal mixture.

Since the commercialization of Baker’s yeast, there have been many attempts engineer yeast to become better leavening agents. Maltose is the most abundant fermentable sugar in bread dough and therefore, the ability to metabolize maltose correlates with the leavening capabilities of the dough. Many studies have aimed to increase the efficiency of the maltose fermentation pathway in dough though gene deletions or modifications in the maltose fermentation pathway or other metabolic pathways.

Those of you who have experience with bread making, what do you notice affecting leavening ability the most? Type of flour, type of sugar, temperature, fat content, etc?

Lastly, I would like to share the recipe below that I used to obtain the super bubbly yeast mixture pictured above.



INSPIRATION: This recipe is modified from Brown Eyed Baker‘s American Sandwich Bread

YIELD: one 9 by 5 inch loaf

TIME: three hours

3 3/4 cups (18 3/4 ounces) unbleached all-purpose flour
2 teaspoons salt
1 cup buttermilk
1/3 cup water
2 tablespoons unsalted butter
3 tablespoons honey
2 1/2 teaspoon active-dry yeast

1. Proof the yeast: Mix buttermilk, butter, honey and water mixture and heat to approximately 110 degrees. It is better to be slightly on the cool side than on the hot side as too high of a temperature can kill the yeast. Add the yeast and mix until dissolved. Wait about 10 minutes to proof the yeast.

2. Attach a dough hook to a standmixer. Mix 3 3/4 cup of flour and salt in a stand mixer bowl on low speed. Slowly add the liquid while the mixer is still on low. When the dough comes together and looks more or less uniform, bring the mixer speed up to medium for 10 minutes. If needed, pause the mixer and scrape down the sides of the bowl. If the dough is still sticky after 10 minutes, add a 1 tablespoon of flour at a time until the dough is no longer sticky (I had to add about 2 tablespoons).

3. Remove dough from the mixer bowl and kneed into a smooth, round ball. Grease the mixer bowl and place the dough back into the bowl. Cover with plastic wrap and let the dough rise until it doubles in size (about one hour).

4. When doubled, deflate the dough and roll out into a rectangle approximately 1 inch thick and no more than 9 inches wide. With the 9 inch side facing you, roll the dough away from you firmly into a cylinder, stopping to press the dough together as you roll to make sure the dough sticks to itself. Pinch seams together and place into a greased 9 by 5 inch loaf pan seam side down. Cover with plastic wrap and set aside until dough doubles (about 30 minutes).

5. Meanwhile, place one oven rack at the lowest position and place the other at the middle position. Heat the oven to 350 degrees. Place an empty baking pan on the bottom rack. Bring water to a boil in a small saucepan or kettle. Pour the boiling water into the empty pan on the bottom rack until it covers the entire surface. Place the loaf pan into the middle rack. Bake for 40 minutes or until an instant-read thermometer inserted into the middle of the bread reads 195 degrees. Remove the bread from the pan and transfer to a wire rack. Cool completely before storing bread in an airtight container.

CC BY-NC-ND 4.0 Yeast on the Rise by Jennifer Tsang is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

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