Cream of Tartar is a white, powdery substance derived from the acidic residue left in wine barrels after fermentation. Its chemical name is potassium bitartrate, and it is commonly used in cooking and baking. It helps stabilize egg whites when making meringues and can prevent sugar from crystallizing in candies. In addition to its culinary uses, Cream of Tartar can also serve as a leavening agent when combined with baking soda. This combination produces carbon dioxide gas, which helps baked goods rise. It is often found in recipes for cakes, cookies, and other desserts.