How Yeast Makes Bread Rise

While many people view cooking as an art form, baking is more closely related to science, specifically chemistry. Different chemical compounds combine, and friction and heat are added to achieve specific flavors and textures. Ingredients need to be in proper proportion to each other if they are going to give you the right end result. If the balance is off, you may end up with a product that tastes faintly of alcohol or that does not rise.

Nowhere is this truer than in yeasted dough. Yeast and steam are the two most common ways to make your baked good rise but yeast is by far the pickier of the two. It has to be dealt with carefully to end up with a great loaf of bread. If you do not take care to handle your yeast dough properly, they may not rise or develop any flavor.

When working with yeast, it is important to remember you are dealing with a living organism. Temperature and environment are key! Yeast is at its optimum temperature for fermentation between 90 and 100 degrees Fahrenheit. If they are too cold, their digestive process slows down below 50 degrees F. The efficiency of the yeast decreases when the temperature surpasses 100 degrees. Above 122 degrees, most yeast cells die.

When you add your activated yeast to the dough, they begin to digest the sugars that are present, turning them into carbon dioxide and ethanol. Often, people wonder why it is necessary to knead dough for such a long period of time. By kneading the dough, you develop a material called gluten. The gas produced by the yeast becomes trapped in the gluten to create little pockets of air. This grid of air and gluten gives bread its familiar texture. If the rising process is not allowed to continue for long enough, or if the gluten has not been developed for long enough, the bread will be dense and unappetizing.

By allowing the bread to rise in a warm spot, the yeast not only produces these air pockets, but also develops the flavors of the dough. The alcohol, which is a byproduct of the fermentation process, plays a key role in flavor enhancement. However, if the bread is allowed to rise for too long, it may have a faint aftertaste of alcohol once it is baked or it may fall in the oven.

Most yeast bread recipes call for “punching down” the down in the middle of the rising process. Instead of actually punching your bread, you should try folding it over on itself several times. This process has two important results. First, it redistributes the yeast to allow for more even growth. Second, it releases some of the gas produced which allows the flavor to continue developing without the bread rising too far.

Salt and fats slow the yeast’s digestion, which is why it is critical to have the proper amounts of these ingredients in your baked goods. You want to be careful to not add the salt directly to the yeast and water mixture, because too much can kill them. Instead, add the flour and then add the salt on top of that. If you want to understand why salt is important in a dough, taste a basic bread dough before you add it. It will have almost no flavor but flour. Now add the salt, mix thoroughly, and taste again – the flavor comes alive as the salt interplays with the flavors created by the yeast and flour.

It takes practice to create successful breads, but it is worth the effort. Treat your ingredients with respect, particularly when you are working with a living organism like yeast. Happy baking!