Replace 1/2 teaspoon cream of tartar with 1 1/2 teaspoons lemon juice or white vinegar. If it's paired with baking soda as a leavener, use 1 teaspoon baking powder instead of 1/4 teaspoon soda plus 1/2 teaspoon cream of tartar.
Ratios from university extension services and King Arthur Baking. Checked .
Cream of tartar substitutes, best first
- For 1/2 tsp cream of tartar1 1/2 tsp lemon juice or white vinegarBest for: whipped egg whites, meringue, snickerdoodles
Colorado State. Iowa State lists 1 Tbsp for 1 Tbsp; Colorado's 3:1 ratio is used here.
- For 1/2 tsp cream of tartar + 1/4 tsp baking soda (as leavening)1 tsp baking powderBest for: cookies, cakes that use both
Reverse of King Arthur's homemade baking powder formula.
Why the swaps work
Cream of tartar is a dry acid. Paired with baking soda it makes carbon dioxide (Purdue); in egg whites, acid helps stabilize the foam.
Questions people ask
What can I use instead of cream of tartar in meringue?
Lemon juice or white vinegar, about 3 times the amount of cream of tartar (Colorado State).
Can I just leave cream of tartar out?
In leavening, no—the soda needs an acid. Swap in baking powder or lemon juice/vinegar instead.
Sources
- Ingredient Substitutions, Fact Sheet 9.329 (Colorado State University Extension)
- Substitutions for Common Foods (Iowa State University Extension AnswerLine)
- The difference between baking soda and baking powder, plus substitutions (King Arthur Baking)
- Substitutions and Equivalents in Food Ingredients, CFS-145-W (Purdue Extension)