I very seldomly use cream of tartar, so one box has lasted me several years. Whenever I clean out my pantry, I’m tempted to throw it away, because storage space in my home is literally that precious. I recently made a batch of cookies that, surprisingly, required cream of tartar. I didn’t have any on hand and didn’t have time to buy more. Luckily, I found a website that provided a simple and effective substitute for cream of tartar. I also finally learned what it does. It turns out that cream of tartar is an acid that reacts with baking soda to create carbon dioxide gas, thus acting as a leavener. Cream of tartar can also stabilize whipped egg whites (by maintaining the air bubbles) and prevent crystals from forming in simple syrup.
I made two batches of those cookies, one using cream of tartar and one using the substitution. Both batches of cookies were delicious and beautifully leavened. I’ll never buy cream of tartar again.
How to Substitute for Cream of Tartar
Note: See here if you are looking to substitute cream of tartar in whipped egg whites or simple syrup. I have currently only tested the substitution in cookies.
1 part baking soda to 2 parts white vinegar
For example, if your cookie recipe calls for 1 teaspoon of baking soda and 1/4 teaspoon of cream of tartar, omit the cream of tartar and use 2 teaspoons of white vinegar.