Buttermilk substitutes
Best swap: Milk + lemon juice or vinegar. Use 1 tbsp lemon juice or white vinegar plus 1 cup milk (dairy or plant), minus 1 tbsp per 1 cup.
Buttermilk is mildly acidic, and that acid does two jobs: it tenderises the crumb and reacts with baking soda to help things rise. Any good substitute needs to bring that same tang, so the easy fixes all add an acid to milk.
What to use instead of buttermilk
2. Plain yogurt, thinned
3. Milk + cream of tartar
4. Sour cream, thinned
Buttermilk substitutes: common questions
What is the best substitute for buttermilk in baking?
Stir 1 tablespoon of lemon juice or white vinegar into enough milk to make 1 cup, then rest it 5 to 10 minutes until it curdles. It behaves just like buttermilk with baking soda and works in almost any bake.
Can I use regular milk instead of buttermilk?
Plain milk alone lacks the acid buttermilk provides, so bakes leavened with baking soda will not rise as well and lose some tang. Add 1 tablespoon of lemon juice or vinegar per cup of milk to fix this.