Keeping it Light

Leavenings work biologically or chemically, but either way, they do the same thing: give off carbon dioxide. They produce different textures and flavors, but the big practical difference is speed. The biological kind takes its time, so a dough made with this sort of leavening needs to rise before baking. Chemical leavenings produce carbon dioxide in high gear, making quick breads feasible, and work in batters that are more liquid.