Quick answer
For whipped egg whites, lemon juice or white vinegar can often provide the acid cream of tartar supplies. If you need cream of tartar because you are making baking powder, the tested formula for 1 teaspoon baking powder is 1/4 tsp baking soda + 1/2 tsp cream of tartar + 1/4 tsp starch—so if the cream of tartar itself is missing, use commercial baking powder instead of trying to recreate that formula without its acid.
Best substitute by job
| Why the recipe uses it | Practical option | Important change |
|---|---|---|
| Stabilize egg-white foam | Lemon juice or white vinegar | Adds acid; exact performance varies by recipe |
| React with baking soda | Use a tested alternative acid or commercial baking powder | Leavener balance may need reformulation |
| Snickerdoodles | Prefer a recipe developed without cream of tartar | Tang, spread, browning and texture can change |
| Prevent sugar crystallization | Lemon juice may work in some syrups | Flavor/acidity can differ |
For meringue and whipped egg whites
Cream of tartar lowers pH and helps stabilize egg-white foam. Lemon juice or vinegar can provide acidity, but a substitution should follow the specific meringue recipe when precision matters.
For snickerdoodles
Cream of tartar is part of the cookie's characteristic tang and interacts with baking soda. Simply removing it or replacing it with an unrelated ingredient changes more than flavor. A tested baking-powder-based snickerdoodle recipe is safer than an improvised one-for-one swap.