Question

how to bake a bread without using yeast cells

Answer 1

As bread dough is mixed and kneaded, millions of air bubbles are trapped and dispersed throughout the dough. Meanwhile, the yeast in the dough metabolizes the starches and sugars in the flour, turning them into alcohol and carbon dioxide gas. This gas inflates the network of air bubbles, causing the bread to rise. During rising, the yeast divides and multiplies, producing more carbon dioxide. As long as there is ample air and food (carbohydrates) in the dough, the yeast will multiply until its activity is stopped by the oven’s heat.

Most homemade bread recipes call for an hour or two of rising. This will produce perfectly fine bread, but if you want more artisanal results, give your dough a long, slow rise by putting it in a cool spot, such as the refrigerator. This allows more time for fermentation, which creates desirable secondary flavors that counterbalance the yeast’s earthiness. Along with the yeast, bacteria are growing in the dough as it rises. The bacteria often include some of the same lactic-acid-producing bacteria that turn milk into yogurt, which gives slow-risen breads a delicious tang.

In most bread recipes, the dough rises twice, once before the loaf is formed, and once after. During the first rise, heat from fermentation builds up in the center of the dough ball, the multiplying yeast gets packed into clusters, and alcohol builds along with the carbon dioxide that is rising the dough. Punching down or stirring a dough at this point before forming it into a loaf refreshes the yeast’s environment, evening out the hot and cold spots in the dough, breaking up overcrowded yeast clusters, and releasing the buildup of alcohol, which would result in off flavors and could create a toxic environment that kills the yeast. With a fresh start, the yeast is better able to aerate the loaf during the second rise, just before baking.