Cream of Tartar is the common name for potassium hydrogen tartrate. This white odorless powder is an important byproduct of wine manufacturing. Cream of Tartar is commonly used in cooking and also for cleaning. Cream of Tartar powder is now available in any supermarket. It is an acid salt found as sediments in the barrels used for fermenting wine. Cream of tartar is produced from argols which are formed on the inner walls of Wine Vats during fermentation. A torch is used remove the argols which are then dried and baked in a furnace at 900 degrees and then ground to a powder followed by treatment with Sulfuric acid and carbonate and finally with carbon to remove any color.
The history of Cream of Tartar dates back to 7000 years. Traces of calcium tartrate sediments was found in a wine making jar discovered in the ruins of a village in northern Iran. The modern process for manufacturing Cream of Tartar was developed by the Swedish chemist CW Scheele in 1769. Later the properties of Cream of Tartar was discovered by Jean Baptiste Biot in 1832. The powder has the property of rotating polarized light. Apart from that, Cream of Tartar burns into a blue flame indicating the presence of high potassium content in the salt. The uses and process of preparing the Cream of Tartar was further perfected in French cuisine.
Potassium bitartrate crystallizes on the walls of the wine barrels. The crude form also known as beeswing are scrapped off from the walls of the barrels. The scrapped wet tartrate is then dried open and later allowed to be baked in a hot blazing furnace at very high temperatures(800-900 degree Celsius) . After the completion of heating process, the hardened sediments are then purified and grounded to obtain a white powder. One portion of the powder is mixed with sulphuric acid whereas the other half is mixed with carbonate soda. Both the mixtures are blended together and this process produces the colorless powder of Cream of Tartar. Carbon block is used to remove odor of wine from the Cream of Tartar.
Cream of Tartar has multiple uses in food making and household purposes. It is commonly misunderstood with sodium acid pyrophosphate because of its similar function as a baking powder.