Cream of Tartar a mildly acidic substance used as an ingredient of baking powder, and occasionally to give a sour taste to soft drinks. In the food industry it is also used to help sugar to ‘invert’ in the making of syrup.
Scientific names for cream of tartar are acid potassium tartrate and dipotassium L-(+)-tartrate. It is an ‘acid salt’; that is, a salt formed by the partial neutralization of an acid so that the product remains slightly acidic.
It is usually made by purifying tartar, the whitish crystals which precipitate out of wine. This is also a source of tartaric acid, which is an alternative constituent of baking powder.