Cookbook:Baking Powder

| Basic foodstuffs | Leavening agent

Baking powder is a chemical leavening agent.

Characteristics
Baking powder is composed of baking soda, one or more acidic salts (such as cream of tartar or dicalcium phosphate dihydrate), and a powdered starch to act as a buffer.

When the baking powder is combined with liquid, the baking soda reacts with its component acids to produce carbon dioxide gas bubbles, which are trapped by the material around them and cause leavening.

Early baking powders were single-acting, meaning that they react very quickly at room temperature and release most of their gas before making it into the oven. Most modern baking powders are double-action, which means they contain both fast- and slow-acting acids. The fast-acting acid dissolves quickly and reacts to produce carbon dioxide at room temperature, and the slow-acting only reacts once heat causes it to dissolve completely. Double-acting baking powders are therefore more stable and prevent rapid gas release from negatively impacting the structure of a leavened good.

Selection and storage
Despite the buffering starch, the acid and base components of baking powder will still slowly react together over time, decreasing its leavening power. As a result, baking powder is only guaranteed to have its full leavening power for up to ½–1 year.

Use
Baking powder is used as a leavener in recipes that don't otherwise have acidic ingredients to react with baking soda. It is often found in quick breads like pancakes, waffles, and muffins.