Cream Of Tartar
The white powder that keeps your meringue stiff and your snickerdoodles tangy. It is a natural byproduct of winemaking, and it does things in baking that nothing else quite replicates.
What It Is
Cream of tartar is potassium bitartrate, an acid salt that forms inside wine barrels during fermentation and is then refined into a fine white powder. It has no flavor of its own, but it changes the texture and chemistry of whatever it touches.
Bakers use it to stabilize whipped egg whites so they hold their peaks longer, to prevent sugar syrups from crystallizing, and to give snickerdoodles their distinctive slightly sour bite. It also reacts with baking soda to create leavening, which is exactly how most homemade baking powder is made.
What To Do
To make your own baking powder, mix one part baking soda with two parts cream of tartar. For meringue or royal icing, add about one eighth teaspoon per egg white before you start whipping. For snickerdoodles, the recipe will call for it directly in the dough, and you should not skip it.
Store it in a sealed container away from moisture and it will keep for years. Start with small amounts since a little goes a long way, and too much can leave a faintly metallic taste in delicate recipes.
