Argol

Argol is a crude variety of cream of tartar which forms a crust in the interior of wine-vats and wine-bottles. Originally, it exists in the juice of the grape; but during fermentation much alcohol is developed, which causes precipitation, as argol is very sparingly soluble in an alcoholic liquid. Some wines are not fully ripe when they are bottled, and more alcohol being thereafter developed, a further precipitation of argol takes place as a crust in the bottles, hence the term crusted port. Argol is generally of a reddish tinge, but sometimes is grayish-white. Argol, called in commerce crude tartar, is used for the preparation of Cream of Tartar (q.v.) and Tartaric Acid (q.v.). The constituents of argol are bitartrate of potash (cream of tartar), tartrate of lime, with colouring and extractive matters.