Tartaric acid

Tartaric acid is a food acid that appears as colorless crystals or a white crystalline powder. The federal food regulations note that it is obtained as a by-product of wine manufacture, and it is recognized for use as a flavor enhancer, flavoring agent and pH control agent, among other roles.

Bakers and confectioners use it to give candies, fruit fillings, sorbets and sugar coatings a clean, sharp sour taste. It is also the acid behind cream of tartar, its potassium salt, which stabilizes whipped egg whites and helps leaven cakes when combined with baking soda.

Because it is strong, only a small pinch is needed, and it is usually dissolved in the liquid or mixed with sugar before use.