Argol is a white crystalline substance that forms on the inside of wine barrels during fermentation. Also known as wine diamonds, it is composed of potassium bitartrate and is often used in cooking as a natural leavening agent or tenderizer. Other synonyms for argol include cream of tartar, wine crystals, tartaric acid, and potassium hydrogen tartrate. In addition to its culinary uses, argol has also been used in traditional medicine to help alleviate constipation and relieve heartburn. Though argol may not be a common household name, its presence in our food and history cannot be ignored.