Buttermilk works in some recipes but not all—it depends on what the milk does in that dish
Buttermilk can replace regular milk in baking and cooking, but the swap changes the final result because buttermilk is thicker, more acidic, and tangier than whole milk. In recipes where milk is mainly a liquid ingredient—pancakes, waffles, biscuits, cakes—buttermilk often works well and may even improve texture. In recipes where milk provides richness or neutral flavor—creamy soups, mashed potatoes, coffee—buttermilk will make the dish noticeably sour and thinner. The acid in buttermilk also reacts with baking soda, which can be an advantage or a problem depending on what else is in the recipe.
The short answer: use buttermilk as a milk substitute only in baked goods and dishes that already call for an acidic ingredient like lemon juice or vinegar. Avoid it in savory creamy dishes, sauces meant to be mild, or any recipe where neutral flavor matters.
Key Takeaways
- Buttermilk works best in pancakes, waffles, biscuits, cakes, and quick breads because the acid helps them rise and creates tender crumbs.
- Do not use buttermilk in creamy soups, mashed potatoes, or sauces where you want a mild, rich flavor—the sourness will be noticeable and unwelcome.
- When you substitute buttermilk for milk in a recipe with baking soda, reduce the baking soda slightly because the acid will set up it on its own.
- Buttermilk is thicker than milk, so use the same volume but expect a denser, more tender final product.
- If a recipe calls for buttermilk and you have only regular milk, add lemon juice or vinegar to mimic the acidity rather than using milk straight.
Baked goods where buttermilk is a direct swap
Buttermilk works as a one-to-one replacement for milk in pancakes, waffles, biscuits, scones, and quick breads like banana bread or zucchini bread. The acid in buttermilk reacts with baking soda to create lift and a tender crumb. If the recipe already calls for baking soda, use buttermilk without changing anything else. The result will be slightly tangier and more tender than if you had used regular milk.
For cakes that use baking powder instead of baking soda, buttermilk also works, though the tang will be more noticeable in the final flavor. Chocolate cakes, carrot cakes, and spice cakes often benefit from this swap because the sourness balances sweetness. Vanilla cakes and delicate cakes like angel food are less forgiving—the buttermilk flavor can overpower the cake.
When to avoid buttermilk as a milk substitute
Do not use buttermilk in creamy soups, chowders, or any dish where milk provides richness and neutral flavor. Buttermilk will make potato soup, cream of mushroom soup, or mac and cheese taste sour and thin. The same applies to mashed potatoes, gravy, custard, pudding, and cream-based sauces. These dishes rely on milk's mild taste and smooth texture, and buttermilk disrupts both.
Avoid buttermilk in coffee, tea, or any beverage where you want milk to add creaminess without changing flavor. Buttermilk will curdle slightly in hot coffee and will taste noticeably tangy. For scrambled eggs, omelets, and quiches, regular milk is the safer choice unless you specifically want a tangy edge.
Adjusting baking soda when you use buttermilk
If a recipe calls for milk and baking powder, you can swap in buttermilk without changing the baking soda or baking powder. But if a recipe calls for milk and baking soda, you need to reduce the baking soda slightly because buttermilk's acid will set up it on its own. For every cup of buttermilk, reduce the baking soda by one-quarter teaspoon.
This matters because too much baking soda creates a metallic or soapy taste and can make the crumb coarse and tunneled. If you forget to reduce it, the baked good will still rise, but the flavor and texture will suffer. Write the adjustment on your recipe card so you remember it next time.
Buttermilk thickness and how it changes your result
Buttermilk is thicker than whole milk because it contains less fat and more milk solids. When you use it as a one-to-one swap, you are using the same volume but a denser liquid. This means your batter will be slightly thicker, and your baked good will be slightly denser and more tender than if you had used regular milk.
In pancakes and waffles, this is usually an improvement—the result is fluffier and holds together better. In cakes, the crumb will be more tender and slightly more moist. In biscuits, the dough will be slightly stiffer, which can make them easier to handle. If you want the exact same texture as the original recipe, you can thin the buttermilk by adding a tablespoon of water per cup, though this is rarely necessary.
Buttermilk flavor in sweet versus savory dishes
The tang in buttermilk is welcome in sweet baked goods because it balances sugar and enhances vanilla, chocolate, and spice flavors. In pancakes, waffles, and cakes, most people do not notice the sourness—they notice that the baked good tastes richer and more complex. The acid also helps brown the outside of baked goods, creating better color.
In savory dishes, the tang is usually unwelcome. Buttermilk will make a cream sauce taste sour, a soup taste thin and acidic, and mashed potatoes taste like they have curdled. If you are cooking savory food and have only buttermilk, use regular milk instead or save the buttermilk for baking.
How to make a buttermilk substitute if you need it
If a recipe calls for buttermilk and you have only regular milk, you can create a substitute by adding acid. Pour one cup of regular milk into a bowl and stir in one tablespoon of lemon juice or white vinegar. Let it sit for five to ten minutes—it will curdle slightly and thicken. This substitute works in any recipe that calls for buttermilk, including baking and cooking.
The substitute will not taste exactly like real buttermilk because it lacks the tangy bacteria, but it will provide the acidity and thickness that most recipes need. If you use this method, do not reduce the baking soda—the substitute is less acidic than real buttermilk, so you need the full amount.
Frequently Asked Questions
Can I use buttermilk in mac and cheese?
No. Buttermilk will make the sauce taste sour and thin. Use whole milk or half-and-half instead. If you have only buttermilk, make the sauce with it and then stir in a small amount of cream or butter to balance the sourness, though the dish will not taste the same.
Does buttermilk change the rise in cakes with baking powder?
Buttermilk will not prevent a cake from rising if the recipe calls for baking powder. The cake will rise normally, and the buttermilk will make the crumb slightly more tender. You do not need to adjust the baking powder.
Why does buttermilk curdle in hot coffee?
Buttermilk curdles in very hot liquid because the acid in it reacts with heat. The curdling is harmless but looks unappetizing. Use regular milk in hot beverages instead.
Can I use buttermilk in gravy?
Buttermilk will make gravy taste sour and thin. Use whole milk, half-and-half, or broth instead. Buttermilk is not a suitable replacement for milk in savory sauces.
What if I use buttermilk but forget to reduce the baking soda?
The baked good will still rise and be edible, but it may have a slightly metallic or soapy taste and a coarse, tunneled crumb. The flavor and texture will not be ideal, but the mistake is not a disaster. Next time, remember to reduce the baking soda by one-quarter teaspoon per cup of buttermilk.