It’s alive!!! You heard me, yeast is a living thing! There are actually over 1,500 species of yeast, classified in the kingdom Fungi. These single celled fungus are most often used for baking and beer making. Two of my favorite things, I might add. I’m not a brewer, so I’m just going to talk about how yeast works when it comes to bread making.
Let’s go way back to freshman biology class. Try to pay a little more attention than you did back then, because you might actually have a reason to apply some of this knowledge.
Cell Mitosis. Does that ring a bell? It’s when a single cell literally divides it’s self from the nucleus and separates, creating two cells. This is how yeast “grows”. In order to grow, the existing yeast needs two things: to stay warm and to have food. Yeast’s favorite food is sugar. The little yeasties convert the sugar into gas. Mostly carbon dioxide and ethanol. During the baking process, the gas is released by the yeast, creating little bubbles, or air pockets, in the dough. But what about the temperature?! The yeast can’t survive the hot dry temperatures of the baking process! It’s okay… We fed the yeast it’s last meal of sugar before we sent it off to it’s death. Yeast can survive, ideally at 40 degrees, grow between 105-115 degrees, and dies a quick death at 140 degrees. Which is convenient for us bakers. Store your yeast in the refrigerator, proof it in warm water, then kill it in the oven.
Most recipes will require you to proof the yeast before adding it to your dough. This is a simple step that jump starts the growth (budding) process. Because the yeast has been laying dormant in your refrigerator (40 degrees), you need to wake it up. Mix the specified amount of warm water (110 degrees) with sugar and dissolve the yeast with it. Then let it sit for about 5 minutes. It will “proof”, growing and foaming. Some recipes will add salt into the proofing process. Salt inhibits the growth process, therefore resulting in a less fluffy texture, such as a nice French loaf.
Before proofing. After 5 minutes of proofing.
After adding the proofed yeast to your dough, there is typically a rising process or two. Basically allowing the yeast to continue it’s growing phase inside the dough to create those tiny air pockets. Once again, the yeast needs to stay warm and the dough needs to stay damp (to prevent it from getting crusty and dry before baking). I like to put my dough in a greased bowl and cover it with a warm damp towel, then let it sit in an unheated oven. The oven provides an environment free from air conditioning, drafty breezes and other climate changes that could be detrimental to your yeast growth. The microwave is also an acceptable alternative.
Before rising. After rising, 1 hour.
The second rise is always a tricky one. Most recipes requiring a second rise will instruct you to roll the once risen dough, out or into a specific shape and then allow the second rise to happen in it’s new formation. For this I would recommend covering your dough with plastic wrap that has been sprayed with a non stick cooking spray. It allows for easy removal without disturbing the surface of the dough and ruining the shape you want. The less you touch the dough after the second rising, the better. Let it rise on the baking sheet you’ll be using.