cream of tartar

Cream of tartar, chemically known as potassium bitartrate (KC₄H₅O₆), is an acidic salt derived from the sediment that forms during wine fermentation. This natural byproduct crystallizes on the interior of wine barrels and is then refined and pulverized into a fine, white powder. It is flavorless and odorless, composed of tartaric acid and potassium.

Cream of tartar is a food-grade acid used as a stabilizing and leavening agent. It has a slightly acidic pH (approximately 3.6 in solution) and works synergistically with baking soda to produce carbon dioxide, creating rise in baked goods. It is distinct from other acidic baking ingredients in its purity and neutral flavor profile.

Cream of tartar is primarily employed in baking as a leavening agent when combined with baking soda, producing a mild, CO₂-based rise ideal for cookies, cakes, and quick breads. It stabilizes egg white foams, a critical function in meringues, soufflés, and angel food cakes, where it prevents overbeating and increases volume. The ingredient also functions as a cleanser for copper cookware and is used in candy-making to inhibit crystallization. In savory applications, small amounts appear in spice blends and are occasionally added to boiling water for vegetables to preserve color.