McCormick Cream of Tartar is an ingredient essential to all bakers and especially for holiday baking. It adds texture, volume and lift to beaten egg whites in angel food cake, meringue shells, meringue for pies and 7-minute frostings, resulting in light and fluffy desserts. Cream of tartar, also known as tartaric acid, is a byproduct of the fermentation of grapes into wine. This tasteless baking necessity stabilizes beaten egg whites in desserts and egg dishes. A pinch also helps prevent homemade whipped cream from deflating. To make your own baking powder, mix tsp. cream of tartar and tsp. each baking soda & cornstarch. Make a gentle cleanser for copper cookware by mixing cream of tartar with a little water into a paste.