What is used to provide leavening in quick breads?

Quick breads rely on leavening agents that provide immediate rise during the baking process. Baking soda and baking powder are both chemical leavening agents that create carbon dioxide gas when they react with moisture and heat. This gas gets trapped in the batter or dough, causing it to expand and rise quickly in the oven.

Baking soda requires an acid (like yogurt or buttermilk) to activate, while baking powder contains both an acid and a base and only needs moisture and heat to activate. The speed with which these agents work makes them ideal for quick breads, as they do not require the long fermentation process used in yeast-leavened breads.

In contrast, yeast is a living organism that ferments sugars to produce carbon dioxide gas, but this process takes longer, making yeast unsuitable for quick breads. Egg whites can also provide some leavening through aeration when whipped, but they are not the primary leavening agents used in quick bread recipes. Vinegar is sometimes added in recipes with baking soda to enhance leavening, but it does not function as the main leavening agent itself. Therefore, the primary sources of leavening in quick breads are indeed baking soda and baking powder.