The best substitute to use when you're out of buttermilk

Having a well-stocked pantry, so you can make all of your favorite baked goods at a moment's notice, is something most cooks aspire to. But when it comes to perishable ingredients like buttermilk, sometimes you find yourself in need of a baking substitute. If you really find yourself in a pinch, the best buttermilk substitute is vinegar and milk. 

Buttermilk adds a few different things to your recipes when you bake. It has acidity, protein, and fat, as well as water. When the acid in buttermilk interacts with baking soda, it makes the batter or dough it's being used in rise, resulting in fluffy pancakes, biscuits, and more. The mild lactic acid of buttermilk also helps break down gluten strands, resulting in more tender baked goods (via Fine Cooking). 

You can mimic its properties in a few ways. The simplest is to add 1 tablespoon of vinegar or lemon juice to 1 cup of milk, letting it sit until it's slightly thickened (via Taste of Home). This won't give you the same round, full flavor as buttermilk, but it does have the acid and protein necessary to help your batter or dough rise.

Still, there are ways to improve. Commercially available buttermilk has a thick texture, unlike the watery buttermilk of yesteryear (via King Arthur Flour). Because of the difference in viscosity, milk and vinegar aren't a perfect replica (via Serious Eats).

That's why unsweetened, unflavored kefir, a fermented milk beverage, is the preferred substitute for some bakers (via Milk Street). It has the same thick texture as buttermilk, which means your batters and doughs will have the right structure, and it has the proper acidity to interact with other leaveners. You can use it in all sorts of recipes, too: add it to your smoothies, salad dressings, and even your marinades, where it tenderizes your meat in a manner similar to yogurt. 

If you're not convinced and want another shelf-stable option, consider buttermilk powder. While it also doesn't provide the necessary viscosity for some recipes, it does deliver on flavor and acidity.

If you try these and end up deciding you've just got to have real deal buttermilk ready at all times, freeze your leftovers in ice cube trays next time you buy it. When you're ready to bake, you can thaw what you need, without having to franticly rush to the grocery store or trying to make a substitute (via The Spruce).