Baking powder is a chemical leavening agent. It combines sodium hydrogen carbonate (baking soda, INS 500(ii)) with one or more dry food acids, such as sodium acid pyrophosphate or monocalcium phosphate, plus a starch that keeps the two apart and absorbs stray moisture. When the powder gets wet and warm, the acid and the soda react and release carbon dioxide, forming tiny bubbles that make the dough rise and give a light, tender crumb.
Many commercial baking powders are double-acting: a first burst of gas forms when the dough is mixed and a second when it is heated in the oven. That makes them forgiving in a factory, where dough may wait before it is baked. The starch is often corn starch, though it varies by brand.
On SeekSnack, baking powder is used in Alice’s Coconut Mochi, where it makes up only about half a percent of the recipe.
