Cream of tartar is the powdered form of tartaric acid, a substance that forms at the bottom of barrels when making wine. It is added to recipes for three reasons:
- To stabilize egg whites, when whipping them for meringue: Cream of tartar is the ingredient that helps meringue maintain its high peaks, even after a trip through the oven.
- To act as a leavening agent: In cookies, pancakes and other yeast-free baked goods combine cream of tartar with baking soda, and you get a chemical reaction that makes your treats fluffier.
- To prevent the sugar from crystallizing: In frostings, icings, and syrups using cream of tartar results in a creamier texture.
Cream of Tartar Substitutes
If you don't have any cream of tartar in your pantry, you can use one of these substitutes in its place:
- Beating egg whites: Use an equal amount of white vinegar or lemon juice, or omit the cream of tartar from the recipe entirely
- As a leavening agent: Replace the baking soda and the cream of tartar called for in the recipe with baking powder. Use one teaspoon of baking powder to replace 1/3 tsp of baking soda and 2/3 tsp of cream of tartar. Since baking powder is just a mix of cream of tartar and baking soda, this substitution won't change your recipe at all.
- Frostings and syrups: Leave the cream of tartar out. No substitution is necessary. If you're making a simple syrup that you plan to store for an extended time, it may crystallize eventually, but that can be easily remedied by reheating it in the microwave or on the stove.
Note: While these substitutions will give you good results, the finished product might still come out a bit different than you're used to. Expect subtle changes in texture and appearance. That's just the nature of a substitute.
Whether Cream of Tartar Goes Bad
As long as you keep your cream of tartar in an air-tight container, away from heat sources, it should keep indefinitely. So, don't sweat it if the container in your pantry is so old you don't even remember when you bought it. Just dust it off, and put it back into service. Other baking ingredients, like baking powder, do have a shelf life.