What is the role of baking soda in baking powder?
Baking powder is made up of baking soda, a powdered acid, and cornstarch.
Most baking powders are labeled ‘double-acting’ meaning they release a small amount of carbon dioxide gas when they’re stirred into the batter or dough, but they release a majority of their precious gas when triggered by the heat of the oven.
Because baking powder is a leavener that contains both the sodium bicarbonate and the flavor-saving acid, it is usually paired with non-acid ingredients like whole milk and Dutch-processed cocoa.
Baking soda need an acid. Baking powder has an acid.