Use about twice as much lemon juice as vinegar (1 teaspoon lemon juice per 1/2 teaspoon vinegar). For souring milk, lemon juice swaps 1:1.
Ratios from university extension services and King Arthur Baking. Checked .
Vinegar substitutes, best first
- For 1 Tbsp vinegar (to sour milk)1 Tbsp lemon juiceBest for: homemade buttermilk
Nebraska, Utah State, Purdue.
- For 1/2 tsp vinegar1 tsp lemon juiceBest for: dressings, marinades, baking
Reverse of the extension ratio 1 tsp lemon juice = 1/2 tsp vinegar; Illinois says 1:1.
- For 1 1/2 tsp vinegar (as acid with baking soda)1/2 tsp cream of tartarBest for: baking
Reverse of Colorado State's cream of tartar entry.
Why the swaps work
Vinegar supplies acetic acid for tang and to react with baking soda; lemon juice and cream of tartar supply other acids that do the same job.
Questions people ask
Can I use lemon juice instead of vinegar for buttermilk?
Yes, 1 Tbsp per cup of milk either way.
Can I use cream of tartar instead of vinegar?
When the vinegar is there to activate baking soda, 1/2 tsp cream of tartar replaces about 1 1/2 tsp vinegar.
Sources
- Ingredient Substitutions (Nebraska Extension, UNL)
- Ingredient Substitution, FN 255 (Utah State University Extension)
- Substitutions and Equivalents in Food Ingredients, CFS-145-W (Purdue Extension)
- Ingredient Substitutions and Equivalents, P1690 (Mississippi State University Extension)
- Ingredient Substitutions, Fact Sheet 9.329 (Colorado State University Extension)
- Cooking Substitution Guide (University of Illinois Extension)