Baking Powders and Other Chemical Leaveners

Yeast cells produce carbon dioxide slowly, over the course of an hour or more, so the material surrounding them must be elastic enough to contain it for that much time. Weak doughs and runny batters can’t hold gas bubbles for more than a few minutes, and are therefore usually raised with a faster-acting gas source. This is the role played by chemical leavenings. These ingredients are concentrated, and small differences in the amount added can cause large variations in the quality of the finished food. Too little leavening will leave it flat and dense, while too much will cause the batter to overexpand and collapse into a coarse structure with a harsh flavor.