Cream of Tartar (potassium bitarate), is an acidic byproduct of winemaking, crystals that form on the insides of casks during the fermentation process. They are then scraped and harvested before being ground into a fine powder and incorporated into baking powder, tartaric acid or Cream of Tartar powder. Cream of Tartar is mostly used as a stabilizing agent, added to beaten egg whites to increase their stability and volume when whipped. This makes it extremely useful in the production of meringues and soufflés, two foods that rely heavily on beaten egg whites for their texture and structure. All natural. Naturally gluten free.