Baking powder

Baking powder is a leavening agent in that it creates carbon dioxide in one or more circumstances. Depending on the product, baking powders can range can be fast-acting, slow-acting, or double-acting, depending on the acid or acids they contain. Double acting baking powders normally include two different acids, one activated by heat, and one activated by liquid.

Some vendors use aluminum based additives in their baking powders for stability and shelf life. These additives unfortunately can leave metallic or bitter notes to the foods they are used in.