In bread baking, the leavening agents used are baking powder, dried yeast (also known as active dry yeast or instant yeast), and bicarbonate soda (also known as baking soda). Each of these leavening agents has different characteristics and roles in the bread-making process:
Baking Powder: Baking powder is a chemical leavening agent that contains a combination of an acid (usually cream of tartar) and an alkaline (usually baking soda). When mixed with moisture and exposed to heat, baking powder produces carbon dioxide gas, which causes the dough or batter to rise. Baking powder is typically used in recipes that do not require a significant amount of time for fermentation, like quick breads, muffins, and some cake recipes. It acts quickly, providing a rapid rise to the baked goods.
Dried Yeast: Dried yeast is a live organism, specifically strains of Saccharomyces cerevisiae, that consume sugars in the dough and produce carbon dioxide gas and alcohol through fermentation. This process takes longer than baking powder's action, and it contributes to the bread's flavor development. Yeast is commonly used in traditional bread recipes and requires time for the dough to rise. It produces a slower, more controlled rise and fermentation, resulting in a distinct flavor profile.
Bicarbonate Soda (Baking Soda): Bicarbonate soda is another chemical leavening agent. It requires an acidic ingredient (such as buttermilk, yogurt, vinegar, or citrus juice) to create carbon dioxide gas and cause the dough or batter to rise. Unlike baking powder, bicarbonate soda relies on the presence of acid in the recipe to be activated. It is often used in recipes like buttermilk biscuits or certain types of pancakes where an acidic ingredient is included.
Comparing the leavening power, baking powder tends to produce a more rapid and vigorous rise compared to dried yeast, especially in recipes that require quick baking. However, the use of dried yeast provides the added benefit of flavor development through fermentation, giving the bread a more complex and characteristic taste.
Bicarbonate soda, on its own, will not raise the dough or batter unless there is an acidic ingredient present to react with it. When the bicarbonate soda reacts with an acid, it produces carbon dioxide gas, resulting in a rise. Therefore, it is essential to use an appropriate acidic ingredient in recipes that call for bicarbonate soda.
In summary, while baking powder may produce a more immediate rise in baked goods, dried yeast and bicarbonate soda each serve unique roles in different types of recipes, contributing to the overall flavor, texture, and leavening process in bread baking.