Background: The white powder we know for its various uses in kitchen alchemy is an important by-product of winemaking. Forming initially as a red-brown substance called argol, or beeswing, it matures further into tartaric acid flakes, in the inside of wine casks. Collected, then refined by a process whereby it is neutralized with potassium hydroxide, it is then ground into the fine white powder we commonly know as cream of tartar.

Tartaric acid, known in antiquity as tartar, was first isolated from potassium tartrate, around 800 AD by Persian alchemist Jabir ibn Hayyan. The modern process was developed in 1769 by Swedish chemist CW Scheele. The chirality of tartaric acid was discovered in 1832 by Jean Baptiste Biot, who observed its ability to rotate polarized light. When burned it produces a blue color flame, indicative of its high potassium content. The uses and processes of making cream of tartar were further developed in French cuisine.

Ancient traces of calcium tartrate were found in northern Iran, this is seen as further evidence of a human history of winemaking of more than 70 centuries.

Cream of tartar increases volume and is stabilizing to whipped egg whites: 1/8 tsp per egg white. Gives creamier texture to candies and frostings, and is used in many commercial, sweet food products. Prevents crystallization of sugar syrups. Used in cooking vegetables to reduce discoloration. Used in photography products. Mixed with water, and sometimes vinegar, cream of tartar as a paste is used for cleaning metals such as coins, brass, copper, pans, stove parts and other hard-to-clean metal surfaces.

Older recipes may call for the use of cream of tartar with baking soda. Baking soda now contains both.

Storage: When stored properly, cream of tarter has a virtually infinite shelf-life. When any caking occurs, it can be pulverized for use.

Added to various recipes in very small amounts. It is also used for cleaning metals.