Okay, but really, what is it? Potassium hydrogen tartrate is a potassium acid salt left behind by grapes during the fermentation process. It’s the main acid in winemaking and during the process this acid can crystallize into “wine diamonds” and settle with other sediment at the bottom of whatever vessel is being used to ferment the wine. The crystals are purified and ground into the powder we call Cream of Tartar.
So what do you use this acidic powder for? Often it’s added to baked goods to help activate baking soda to create rise. In fact, baking powder is just baking soda mixed with Cream of Tartar. A pinch can also be added to sugar before it’s cooked to prevent crystallization when making caramels or certain candies. It’s also extremely helpful when making macarons, pavlovas, floating islands or other dishes that use whipped egg whites as the powder stabilizes the air bubble matrix and keeps your meringue stiff.
