How to make buttermilk: three easy substitutes
Out of buttermilk halfway through a recipe? Milk and lemon juice or vinegar make a cup in five minutes. Here are the amounts, two more swaps and how to use buttermilk in place of milk or sour cream.
Short answer: Put 1 tablespoon of lemon juice or vinegar in a measuring cup, add milk to make 1 cup and let it stand for 5 minutes. Use it cup for cup in place of buttermilk. Two other swaps for 1 cup of buttermilk: 1¾ teaspoons of cream of tartar stirred into 1 cup of milk, or 1 cup of plain yogurt.
Three ways to replace 1 cup of buttermilk
The amounts come from US university extension substitution tables; see the sources below.
| Substitute | For 1 cup of buttermilk | Notes |
|---|---|---|
| Milk and lemon juice or vinegar | 1 tablespoon lemon juice or vinegar, plus milk to make 1 cup | Let it stand 5 minutes before using. |
| Milk and cream of tartar | 1¾ teaspoons cream of tartar plus 1 cup milk | Colorado State University Extension gives 1¼ to 1¾ teaspoons. |
| Plain yogurt | 1 cup plain yogurt | Use it as it is. |
Smaller and bigger batches
- ½ cup: 1½ teaspoons of lemon juice or vinegar, plus milk to make ½ cup.
- 1 cup: 1 tablespoon of lemon juice or vinegar, plus milk to make 1 cup.
- 2 cups: 2 tablespoons of lemon juice or vinegar, plus milk to make 2 cups.
- In metric measures: 15 mL of lemon juice or vinegar, topped up with milk to 240 mL, the kitchen cup NIST uses.
Let each batch stand for 5 minutes. Cups, tablespoons and milliliters are explained in the kitchen conversion chart.
Using buttermilk in place of milk or sour cream
- Instead of milk, in baking: for 1 cup of whole milk, use 1 cup of buttermilk plus ½ teaspoon of baking soda, and use 2 teaspoons less baking powder.
- Instead of sour cream: ⅞ cup of buttermilk for 1 cup of sour cream.
Storing buttermilk
USDA’s FoodKeeper gives store-bought buttermilk 1 to 2 weeks in the fridge from the date you buy it, and 3 months in the freezer.
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Where the numbers come from
Read on October 30, 2026.
- University of Nebraska–Lincoln Extension: basic ingredient substitutions (lemon juice or vinegar and milk)
- Utah State University Extension: list of ingredient substitutions (lemon juice or vinegar, cream of tartar, plain yogurt)
- Colorado State University Extension: ingredient substitutions, fact sheet 9.329 (cream of tartar range, buttermilk for milk and for sour cream)
- USDA FoodKeeper (storing buttermilk)
Frequently asked questions
How do you make buttermilk from milk?
Put 1 tablespoon of lemon juice or vinegar in a measuring cup, add milk to make 1 cup and let it stand for 5 minutes. Use it cup for cup in place of buttermilk.
What can I use instead of buttermilk?
For 1 cup of buttermilk: 1 tablespoon of lemon juice or vinegar plus milk to make 1 cup, left to stand 5 minutes; 1¾ teaspoons of cream of tartar stirred into 1 cup of milk; or 1 cup of plain yogurt.
Can I use regular milk instead of buttermilk?
Yes, once you sour it: add 1 tablespoon of lemon juice or vinegar to enough milk to make 1 cup and let it stand for 5 minutes.
Can I use buttermilk instead of milk?
In baking, yes. For 1 cup of whole milk, Colorado State University Extension lists 1 cup of buttermilk plus ½ teaspoon of baking soda, with 2 teaspoons less baking powder in the recipe.
Can buttermilk replace sour cream?
Yes. Colorado State University Extension lists ⅞ cup of buttermilk in place of 1 cup of sour cream.
How long does buttermilk last?
USDA’s FoodKeeper gives buttermilk 1 to 2 weeks in the fridge from the date you buy it, and 3 months in the freezer.
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