What is the primary function of yeast in bread making?

The primary function of yeast in bread making is to serve as a raising agent. Yeast is a living microorganism that ferments sugars present in the dough, producing carbon dioxide gas and alcohol in the process. The carbon dioxide gas is what causes the dough to rise, creating the light and airy texture that is characteristic of well-made bread. This fermentation process also contributes to the development of flavor and texture, but its essential role is in raising the dough.

While yeast does add some flavor during fermentation, that is not its primary function. Additionally, yeast does not serve as a preservative for the bread; rather, its action can actually lead to a shorter shelf life due to the natural fermentation process. Lastly, yeast does not enhance color in the same way that other ingredients might, such as egg wash or certain additives that can achieve a golden crust. Thus, the key role of yeast is fundamentally as a raising agent in the bread-making process.