Milk vs Buttermilk in Baking

Updated September 2026 · Baking Resources

The short version of milk vs buttermilk: buttermilk is acidic and thick, milk is neutral and thin, and that acid is doing real work in the recipe. You can pour milk into a recipe that calls for buttermilk only if nothing in the ingredient list depends on the acid.

Check the leavening. If the recipe uses baking soda, the acid in buttermilk is what makes the gas. Swap in plain milk and you get a flat bake with a soapy, metallic aftertaste from soda that never reacted. If the recipe uses baking powder only, plain milk usually works, and you lose tang and a little tenderness.

That is the whole decision, and it takes five seconds to make once you know where to look.

Updated September 2026

Out of one or the other right now? Our free baking substitutions finder gives you the exact swap ratio, what it changes in the finished bake, and what it cannot fix.

Milk vs buttermilk: what is actually different

Two of those rows matter more than the rest: the pH and the body. Everything people notice about buttermilk bakes traces back to one or the other.

What buttermilk actually does in a recipe

It supplies acid for baking soda

Baking soda is pure base. On its own it makes no gas worth having. Give it an acid and it fizzes off carbon dioxide, which is the lift in pancakes, biscuits, soda bread and most quick breads.

Buttermilk is the most convenient acid a baker has, because it is also the liquid. Well-written recipes rarely ask for more than about 1/2 teaspoon of baking soda per cup of buttermilk, because that is roughly all the acid one cup can neutralize.

It tenderizes

Acid weakens gluten. A biscuit or scone dough made with buttermilk stays softer for the same amount of mixing, which buys you a margin for error. That is a big part of why buttermilk biscuits are famously forgiving.

It thickens the batter

This one gets ignored and it matters. Buttermilk is thick because the culture has partly set the milk proteins. A pancake batter made with it sits up on the griddle instead of running. A batter made with thin milk spreads wider, cooks thinner, and comes out less fluffy even if the chemistry is right.

It adds tang

Not sourness exactly, more of a clean, dairy sharpness that keeps a sweet bake from tasting flat. In cornbread and chocolate cake it does a lot of quiet work.

When you can use milk instead of buttermilk

You can swap plain milk straight in when all of these are true:

1. The recipe has no baking soda, only baking powder.
2. The recipe does not lean on buttermilk for thickness, so no pancakes, no drop biscuits.
3. You are fine losing the tang.

That covers a surprising number of muffins and simple cakes. It does not cover the classics people ask about most, which is why the fix below exists.

The 10 minute fix that solves it

Put 1 tablespoon of lemon juice or white vinegar into a measuring cup. Top it up to 1 cup with milk. Stir and let it sit 5 to 10 minutes until it looks slightly curdled.

That gives your baking soda the acid it needs, and it is chemically close enough to the real thing that almost nobody notices. What it does not copy is the body. Acidulated milk stays thin, so pancake and biscuit batters come out looser than they should.

For thickness as well as acid, use 3/4 cup plain yogurt thinned with 1/4 cup milk instead. Full details and the dairy-free versions are in our buttermilk substitute guide.

When you can use buttermilk instead of milk

Going the other direction is more common than people expect. You have half a carton of buttermilk left, and you want it used up.

Buttermilk usually improves a bake. The crumb gets softer, the taste gets more interesting, and browning often improves. You just have to rebalance the leavening or the acid will drag the rise down.

The rule: for each cup of buttermilk you swap in for milk, add 1/4 teaspoon of baking soda and cut the baking powder by 1/2 teaspoon.

The soda neutralizes some of the added acid and contributes lift of its own. Cutting the powder stops the total leavening from running high, which would give you a bake that rises fast, then collapses.

If the recipe already contains baking soda, you have less work to do. The soda is there because the recipe already had an acid, so adding buttermilk instead of milk usually needs no change at all beyond expecting a thicker batter.

Not sure which leavener is doing what? Our guide to baking soda vs baking powder breaks the difference down in plain terms.

The swap chart

Worked example: pancakes both ways

Take a standard batch: 1 1/2 cups all-purpose flour, 2 tablespoons sugar, 2 teaspoons baking powder, 1/2 teaspoon baking soda, 1/2 teaspoon salt, 1 egg, 2 tablespoons melted butter and 1 1/4 cups buttermilk.

By weight, 1 1/2 cups of spooned and leveled flour is about 188 g and 1 1/4 cups of buttermilk is about 306 g. The grams to cups converter will do that math for any recipe you want to weigh instead of scoop.

Made with real buttermilk. The batter is thick enough to mound on the spoon. It hits the griddle and holds a round shape. The soda meets the acid on contact and again with heat, so the pancakes puff to roughly a half inch. The taste is tangy and the browning is even and deep.

Made with plain milk, no other change. The batter pours thin and spreads to a wide, flat disk. The 1/2 teaspoon of soda has nothing to react with, so it stays in the pancake and tastes faintly of soap. Rise comes from the baking powder alone, and they come out around a third thinner. Edges brown, centers stay pale.

Made with acidulated milk. Stir 1 tablespoon of lemon juice into a cup, fill to 1 1/4 cups with milk, rest 10 minutes. The soda reacts properly, the soapy note is gone, and the rise comes back to about the same as the real thing. The batter is still thinner than buttermilk batter, so the pancakes spread a bit wider and end up slightly less tall. That is the only difference you can see.

Made with yogurt thinned with milk. Closest match of the three fixes. Right acid, right thickness, slightly richer taste.

Scaling that batch up or down for a crowd? The recipe scaler keeps the leavening proportional so you do not end up over-soda-ing a triple batch.

What about the other milks?

Skim or 2% milk. Fine anywhere whole milk is called for. You lose a little richness and tenderness. In a cake with plenty of butter you will not notice.

Powdered buttermilk. Genuinely useful, since it keeps in the pantry for months. Whisk the powder in with the dry ingredients and add the matching water with the wet ones. It gives you the acid but not the thickness.

Sour cream or plain yogurt. Both are acidic and thick. Thin them with milk to a pourable state and they behave much like buttermilk, with more fat. See our sour cream substitute guide for the ratios.

Plant milks. Almond, soy and oat milk all work as milk substitutes, and all of them can be acidulated with lemon juice or vinegar for a buttermilk stand-in. Soy curdles most convincingly. Our dairy-free buttermilk substitute page has the full set.

Evaporated milk. Thicker and slightly cooked-tasting, not acidic. It is a milk substitute, not a buttermilk one, unless you add acid.

The mistakes that cause most failures

Using milk where soda needs acid. The single most common one. Flat bake, soapy taste, no obvious explanation until you check the leavener.

Adding acid to a recipe that already has plenty. If a recipe already contains buttermilk, yogurt, brown sugar and molasses, it may already be acidic enough that adding more throws off the soda balance and leaves a sharp taste.

Boiling buttermilk. Acid plus heat plus low fat means curdled. Buttermilk goes into batters, not into stovetop custards.

Measuring buttermilk in a dry cup. It is thick and clings, so you lose a tablespoon or more to the sides. Use a liquid measure, or weigh it at 245 g per cup. Our measuring guide covers the sticky-ingredient tricks.

Judging by look. Buttermilk separates in the carton. That is normal. Shake it hard before pouring. Separation is not spoilage.

What you gain by getting this right

Getting the milk vs buttermilk call correct is the difference between biscuits that climb and biscuits that sit there. It costs nothing but ten minutes of resting time and one glance at the leavening line of the recipe.

It also stops the mystery failures. Once you know that soda plus no acid equals flat and soapy, an entire category of unexplained bad bakes goes away permanently.

Frequently asked questions

Can I use regular milk instead of buttermilk?

Only if the recipe gets its lift from baking powder alone. If baking soda is in the ingredient list, plain milk gives you a flat result and a soapy aftertaste. Adding 1 tablespoon of lemon juice or vinegar per cup of milk and resting 10 minutes fixes it.

What is the difference between buttermilk and regular milk?

Buttermilk is cultured, so it is acidic at around pH 4.5 and thick, while milk is near neutral at about 6.7 and thin. Buttermilk reacts with baking soda to create lift, softens gluten for a more tender crumb, and adds tang. Milk does none of those things.

Is buttermilk thicker than milk?

Yes, noticeably. The culture partly sets the milk proteins, which is why buttermilk coats the inside of the measuring cup while milk runs clear off it. That thickness is why buttermilk pancake batter holds its shape on the griddle and why a lemon juice substitute never quite matches it.

How much baking soda do I use per cup of buttermilk?

About 1/2 teaspoon per cup is the practical ceiling, since that is roughly all the acid a cup of buttermilk can neutralize. Recipes calling for more are usually raising the pH on purpose for browning or a darker color, not chasing extra lift.

Can I substitute buttermilk for milk in a cake?

Yes, and it often makes the cake better. Swap 1:1, then add 1/4 teaspoon of baking soda per cup of buttermilk and cut the baking powder by 1/2 teaspoon. Expect a softer crumb, a slight tang and a batter that is a little thicker than usual.

Does buttermilk make baked goods rise more?

It does when the recipe pairs it with baking soda, because the acid and the soda together produce carbon dioxide immediately. On its own, buttermilk does not leaven anything. In a recipe with only baking powder, buttermilk can even slow the rise slightly unless you rebalance the leavening.

Why do my buttermilk pancakes taste soapy?

That is unreacted baking soda, which means there was not enough acid in the batter. Either plain milk went in instead of buttermilk, or the substitute did not rest long enough to acidify. Check that you used at least 1 tablespoon of acid per cup of milk and gave it a full 10 minutes.

Does whole milk vs buttermilk change how long something bakes?

Barely. The acid changes texture and lift, not bake time in any meaningful way. What can change the time is the thicker batter sitting deeper in the pan. Judge doneness the usual way, by a clean tester or an internal temperature around 205 to 210°F for a cake.

Related guides

• Buttermilk substitute: 8 easy swaps
• Baking soda vs baking powder
• Dairy-free buttermilk substitute
• Heavy cream substitute
• Evaporated milk substitute