You can substitute buttermilk for milk in most recipes, but you’re not just swapping liquids—you’re swapping acidity. Buttermilk is naturally tangy and reacts with baking soda to create lift, which is why your grandma’s biscuits look like little clouds.
Milk, on the other hand, is neutral. If you sub it straight for buttermilk in a recipe that relies on that acid, expect a flatter, denser result. It’s not a disaster—think of it as a French silk pie versus a cloud pancake.
Pro tip: Add a tablespoon of lemon juice or white vinegar to one cup of milk, let it sit five minutes, and boom—you’ve got DIY buttermilk. That’s a classic Alton Brown move that never fails.
