what does cream of tartar do

Cream of tartar is a dry, acidic byproduct of winemaking that has a myriad of uses in the kitchen, from baking to cleaning coffee stains. It is a versatile ingredient that stabilizes the tiny bubbles in egg whites, speeds up the egg white whipping process, and contributes to a stable, billowy, glossy meringue, perfect for cookies, topping pies, and folding into cake. Cream of tartar is also used as a leavening agent enhancer, flavor enhancer, and to prevent crystallization of sugar, giving that soft, chewy texture in cookies. It can also be used to firm up meringues and keep cooling sugars from rejoining to form brittle crystals. Cream of tartar is similar to both vinegar and lemon juice in its acidity, and each of them will work in its place, in a pinch.