McCormick Gourmet Cream of Tartar is an essential ingredient for bakers. It is used to stabilize beaten egg whites when preparing angel food cake, meringues, macarons and 7-minute frostings, resulting in light and fluffy desserts. Cream of tartar, also known as tartaric acid, is a byproduct of winemaking. A pinch of cream of tartar has a similar stabilizing effect on homemade whipped cream. Cream of tartar also prevents sugar syrup from crystallizing, which is why it is necessary for the soft, chewy snickerdoodles. To make your own baking powder, simply mix 1/2 tsp. cream of tartar and 1/4 tsp. each baking soda and cornstarch. You can also make a gentle cleaner for copper cookware by mixing cream of tartar with a little water into a paste.