Q: What is the difference between baking powder and double-acting baking powder? I notice the stores only sell double-acting and remember reading somewhere that there is a difference.
A: Double-acting baking powder guarantees you a light and airy baked good because it actually rises twice. First, it makes the batter rise when the dry and liquid ingredients are mixed together. It rises again when heat is applied. In fact, you can refrigerate the batter overnight, and still expect a good rise when you put it in the oven the next day.
Single-acting baking powder rises only once, in the oven. If you don’t want the flavor of aluminum sulfate found in double-acting powder, look for the single-acting baking powder in a health food store or a baking supply shop. Or, make your own by combining 2 parts cream of tartar with 1 part baking soda. Make just enough for what you’re making, and use it right away – it loses its rising power quickly.
In fact, don’t let store-bought baking powder sit on your shelf too long, and check the expiration date before you use it. To test it, add 1 teaspoon baking powder to 1/2 cup hot water – if it fizzes, it’s safe to use. If not, buy a new container.