What role does yeast play in bread making?

In bread making, yeast plays a crucial role primarily by fermenting sugars and helping the dough rise. When yeast is mixed with warm water and sugar, it begins to feed on the sugars present in the dough. As it ferments, it produces carbon dioxide gas and alcohol. The carbon dioxide gas gets trapped in the dough, causing it to expand and rise, creating the desired airy texture in the finished bread.

This fermentation process not only contributes to the dough's leavening but also develops flavors and aromas in the bread as a byproduct of yeast activity. While yeast can influence the flavor of the bread, its primary function in the context of this question is its role in fermentation and leavening, making the answer focused on its ability to help the dough rise the most accurate one.

In contrast, while yeast may influence taste and texture, it does not act as a binding agent or preserve freshness in the way that other ingredients or methods might. Thus, its primary significance in bread making lies in its fermentation capabilities, highlighting the process of rising as a vital aspect of creating quality bread.