Cream of Tartar, also called potassium bitartrate or potassium hydrogen tartrate, is a natural by-product of wine production. Crystals, known as “beeswing,” form during fermentation, are collected, purified, and milled into a pale white powder. In cosmetics, it acts as a stabilizer, thickening agent, and pH regulator, essential for effervescent and aerated products such as bath bombs, bath cookies, and bubble bars. It enhances fizziness, stabilizes shapes, creates a smooth, uniform texture, and adds volume, helping ingredients stay bound. Usage: 3–5% by weight in bath bombs, bath bomb icings, and bath truffles.