Buttermilk Substitute Calculator
No buttermilk? Enter how much your recipe needs and pick what you have. You get the exact amounts to mix, how long to leave it, and where the substitute will not pass for the real thing.
Enter your amount and press Calculate.
The acid is doing the work, not the tang
Buttermilk is acidic, and that acidity is what sets off baking soda. Swap in plain milk and King Arthur’s test bakes came out darker and denser, with pancakes that rose less. Adding a tablespoon of vinegar or lemon juice restores the reaction — which is the whole point of the substitute.
What it does not restore is flavour. Real buttermilk is cultured, and fermentation builds a complexity that souring milk for ten minutes does not.
Where the substitute falls short
King Arthur’s rule is a good one: the shorter the ingredient list, the less well a substitute performs. In a spiced cake nobody will notice; in a plain biscuit, the tang is half the recipe.
The bigger gap is thickness. Cultured buttermilk is viscous, and that body is what makes dressings cling and breading stick to fried chicken. Soured milk is thin. For dressings, marinades and fried-chicken brines, use real buttermilk, thinned yogurt or kefir.
What you are actually drinking
A cup of cultured low-fat buttermilk is 98 calories, 8.1 g of protein and 284 mg of calcium. The substitute has the nutrition of whatever milk you made it from, not of buttermilk — a point worth remembering if you are counting anything.
Sources
Nutrition: USDA FoodData Central. Kitchen ratios: King Arthur Baking, America’s Test Kitchen and US university Extension services.
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