Buttermilk substitutes
The best substitute for buttermilk is plain kefir: 1:1, unsweetened. Effectively the same thing: cultured, acidic and pourable. Check it is unsweetened and unflavoured.
Why it matters. Buttermilk is acidic milk. The acid reacts with baking soda to produce lift and it softens gluten strands, which is why buttermilk pancakes and biscuits are tender. Swap in plain milk and a soda-leavened batter will barely rise and the crumb turns tough.
BestPlain kefir
●●●●●1:1, unsweetened
Keeps the acid, liquid and tenderizer roles.
Effectively the same thing: cultured, acidic and pourable. Check it is unsweetened and unflavoured.
Milk + lemon juice
●●●●○1 cup milk + 1 tbsp lemon juice; stir and stand 10 min until it looks slightly curdled
Keeps the acid, liquid and tenderizer roles.
Thinner than cultured buttermilk because it is not thickened by fermentation. Fine in batters and marinades, too watery for a dressing or for drinking.
Milk + vinegar
●●●●○1 cup milk + 1 tbsp white vinegar or cider vinegar; stand 10 min
Keeps the acid, liquid and tenderizer roles.
Same thin texture as the lemon version and slightly sharper. Use white vinegar in pale bakes so the flavour stays neutral.
Plain yogurt + milk
●●●●○3/4 cup plain yogurt whisked with 1/4 cup milk or water
Keeps the acid, liquid and tenderizer roles.
Thicker and slightly more sour than buttermilk. If the batter looks stiff, thin it with another splash of milk.
Sour cream + milk
●●●●○3/4 cup sour cream whisked with 1/4 cup milk
Keeps the acid, liquid and tenderizer roles.
Considerably more fat than buttermilk, so the crumb comes out richer and a little denser.
Milk + cream of tartar
●●●○○1 cup milk + 1 3/4 tsp cream of tartar; whisk the powder into a spoonful of the milk first so it does not clump
Keeps the acid and liquid roles; loses tenderizer.
Provides the acid that baking soda needs but none of buttermilk's tang or body, and it does not tenderise. Baking only.
Soy milk + vinegar
●●●○○1 cup unsweetened soy milk + 1 tbsp lemon juice or cider vinegar; stand 10 min
Keeps the acid, liquid and tenderizer roles.
Soy has enough protein to curdle, which almond and oat milks do not, but it still separates less convincingly and leaves a faint beany note.
Other dairy substitutes
Measuring by weight instead? Use the kitchen converter.