A recipe calls for buttermilk, you do not have any, and buying a whole carton for a quarter cup feels wasteful. Good news: in most baking, you can fake it with things you already have, and the result is close enough that no one will notice.
Why recipes want buttermilk
Buttermilk does two jobs. Its acidity reacts with baking soda to help things rise, and it tenderizes the crumb, giving baked goods a soft texture and a slight tang. Any substitute needs to bring that acidity, or your baking soda has nothing to react with.
The easy stand-ins
- Stir a tablespoon of lemon juice or white vinegar into a cup of regular milk and let it sit a few minutes until it curdles slightly.
- Thin plain yogurt or sour cream with a little milk until it is pourable.
- In a pinch, even a splash of vinegar in plant-based milk works.
Where it matters most
These swaps shine in pancakes, biscuits, muffins, and quick breads, where you just need the acid and a little tang. The milk-and-acid trick is the most reliable one to remember. It is not identical to the real thing, which is thicker and more complex, so for a recipe where buttermilk is the star flavor, the genuine article is worth it. For everyday baking, the substitute is more than fine.