Baking powder consists of baking soda, one or more acid salts (cream of tartar and sodium aluminum sulfate) plus cornstarch to absorb any moisture so a reaction does not take place until a liquid is added to the batter. Most baking powder used today is double-acting which means it reacts to liquid and heat and happens in two stages. The first reaction takes place when you add the baking powder to the batter and it is moistened. One of the acid salts reacts with the baking soda and produces carbon dioxide gas. The second reaction takes place when the batter is placed in the oven. The gas cells expand causing the batter to rise. Because of the two stages, baking of the batter can be delayed for about 15-20 minutes without it losing its leavening power.
Mazda Protege Parts