Cream of tartar Cream of tartar is a leavening agent for dough. It gives pies and cakes more volume and makes them airier.
Cream of tartar is residue that crystallizes and settles on the inside of wine barrels during fermentation. The collected residue is used as a raw material for making cream of tartar.
Many people prefer cream of tartar baking powder because its composition makes it a more natural type of baking powder.