Potassium bitartrate Grapes are the only significant natural source of tartaric acid, and cream of tartar is obtained from sediment produced in the process of making wine. (The journal Nature reported some years ago that traces of calcium tartrate found in a pottery jar in the ruins of a village in northern Iran are evidence that wine was being made more than 7,000 years ago.) Cream of tartar is best known in our kitchens for helping stabilize and give more volume to beaten egg whites. It is the acidic ingredient in some brands of baking powder. It is also used to produce a creamier texture in sugary desserts such as candy and frosting. Cream of tartar can also be used to clean brass and copper cookware.
Price is per ounce.