You can use buttermilk instead of an egg at a ratio of 1/4 cup of buttermilk per egg. That is the cultured-dairy egg replacement, and it works because buttermilk adds moisture, protein and a distinct tang to a batter — the things an egg contributes in a muffin or a quick bread, apart from its leavening and structure. It is the egg substitute to use in pancakes, biscuits, muffins, soda bread and chocolate cake, where the buttermilk's acidity also helps the leavening and its tang is part of the recipe's character. It is not a substitute in recipes where the egg is the structure, and this page explains exactly where that line falls.

Buttermilk as an egg replacer is the choice for bakers who love the tangy, tender crumb that buttermilk gives to baked goods. A pancake made with buttermilk instead of eggs is light, fluffy and tangy, with a golden colour from the buttermilk's acidity reacting with the baking soda. A chocolate cake made with buttermilk has a deep, complex flavour. The swap is simple — measure 1/4 cup of buttermilk per egg and add it where the recipe says to add the egg — and it is one of the most reliable egg replacements in baking, because buttermilk's protein helps the bake hold together and its acidity gives it lift.

The ratio, in a table

The table below converts eggs to buttermilk for the amounts you are most likely to meet. The rule is always the same: 1/4 cup of buttermilk per egg. If you have no buttermilk, you can make a substitute by adding 1 tablespoon of lemon juice or white vinegar to 1 cup of milk and letting it stand for 5 minutes — but that substitute is thinner than real buttermilk, so the result will be slightly less rich.

Eggs called for Buttermilk to use Notes
1 egg 1/4 cup 60 ml
2 eggs 1/2 cup 120 ml
3 eggs 3/4 cup 180 ml
4 eggs 1 cup 240 ml — at the limit
5 eggs 1 1/4 cups Not recommended
6 eggs 1 1/2 cups Not recommended

One large egg weighs about 50 grams, and 1/4 cup of buttermilk weighs about 61 grams — a little heavier, because buttermilk is mostly water. If you are weighing ingredients, that is the number to use. Note that the buttermilk adds water and protein, not fat, so the batter will be slightly wetter than the egg version. That is why the swap works best in recipes that are already moist, and why it is usually limited to three eggs or fewer.

Worked examples

Example 1: Pancakes without eggs

A pancake recipe calls for 1 egg. Replace it with 1/4 cup of buttermilk. The pancakes will be light, fluffy and tangy, with a golden colour — the buttermilk's acidity reacts with the baking soda in the recipe to give extra lift, which more than compensates for the missing egg. This is the best first recipe to try the swap in, because pancakes are forgiving, the buttermilk's tang is part of a pancake's character, and the result is arguably better than the egg version.

Example 2: A chocolate cake with a tender crumb

A chocolate cake recipe calls for 2 eggs. Replace them with 1/2 cup of buttermilk. The cake will be moist and tender, with a deep chocolate flavour that the buttermilk's tang enhances, and it will rise well — because the recipe contains baking soda, the buttermilk's acidity will help it lift. This is a good recipe for the swap, because chocolate covers everything and the buttermilk's tang is an asset rather than a limitation.

Example 3: Soda bread with a lighter crumb

A soda bread recipe calls for 1 egg in addition to the buttermilk already in the recipe. Replace the egg with another 1/4 cup of buttermilk, increasing the total buttermilk by that amount. The bread will be moist and tender, with a tangy flavour and a good rise — the extra buttermilk gives the baking soda more acid to react with. This is the recipe where the swap feels natural: buttermilk is already there, and adding more of it is simpler than adding an egg.

What changes in the result

Three things change when you swap buttermilk for an egg. First, the flavour: buttermilk adds a distinct, tangy flavour that is more pronounced than yogurt's. In pancakes, biscuits, soda bread and chocolate cake, that tang is welcome; in a vanilla cake, it can taste sour, which is why a flax egg or applesauce is safer there. Second, the texture: the bake will be moister and more tender, because buttermilk's acidity weakens gluten and produces a softer crumb. Third, the leavening: buttermilk's acidity activates baking soda powerfully, so a recipe that contains baking soda may rise better with buttermilk than with eggs. If the recipe uses only baking powder, the acidity is neutralised and there is no leavening benefit — but the moisture and tenderness remain.

The practical consequence is that buttermilk is a good moisture, binding and leavening replacer and a poor structure replacer. It works in pancakes, muffins, quick breads, soda bread and chocolate cake, where the egg's job is mostly moisture and the recipe has other ingredients providing structure. It does not work in recipes where the egg provides lift, structure or aeration.

When not to substitute

Do not use buttermilk in meringues, custards, angel food cake, or any recipe where egg is the main structure. Buttermilk cannot whip to peaks, it cannot set into a custard, and it cannot provide the lift that beaten eggs give a sponge. Do not use it in a recipe that calls for more than three eggs — beyond that, the recipe relies too heavily on eggs. Do not use it in a vanilla cake or a delicate white cake, where its tang would be noticeable. And do not use a buttermilk substitute made from milk and lemon juice if the recipe needs the real thing's thickness — the substitute is thinner and will make the batter wetter. Use real buttermilk when you can, and the substitute only when you must. The swap is for sweet and savoury baking where the tang is welcome, and even there it is best in strongly flavoured recipes.

One more caution: buttermilk curdles if it is heated too quickly, so do not use it in a recipe where the egg is added to a hot mixture. In baking, the buttermilk goes into a cool batter and heats gradually in the oven, which is fine. In a sauce or a custard, the same swap would fail.

Frequently asked questions

How much buttermilk do I use instead of 1 egg?

Use 1/4 cup of buttermilk for 1 egg — about 61 grams by weight. For 2 eggs, use 1/2 cup; for 3 eggs, use 3/4 cup. Use real buttermilk when you can, and do not use it to replace more than three eggs in a single recipe.

Can I use buttermilk instead of eggs in pancakes?

Yes — pancakes are the best recipe for this swap. Replace each egg with 1/4 cup of buttermilk. The pancakes will be light, fluffy and tangy, with a golden colour, because the buttermilk's acidity reacts with the baking soda to give extra lift. This is one of the few egg replacements that can actually improve a recipe.

How do I make buttermilk if I do not have any?

Add 1 tablespoon of lemon juice or white vinegar to 1 cup of milk, stir, and let it stand for 5 minutes until it thickens slightly. That is a buttermilk substitute, and it works for this swap — but it is thinner than real buttermilk, so the result will be slightly less rich. For the best result, use real cultured buttermilk, which is thicker and tangier.

Is buttermilk the same as yogurt for baking?

They are similar but not identical. Both are cultured dairy products that add moisture and tang, and both swap at the same ratio for eggs. Buttermilk is thinner and tangier than yogurt, and its acidity is stronger, so it gives more lift with baking soda. Yogurt is thicker and richer, so it gives a more tender crumb. For pancakes and soda bread, buttermilk is the better choice; for cakes and muffins, either works.

Does buttermilk make cakes rise better?

Yes, if the recipe contains baking soda. Buttermilk is acidic, and its acidity reacts with baking soda to produce carbon dioxide, which lifts the cake. The reaction is stronger than with yogurt, because buttermilk is more acidic. If the recipe uses only baking powder, the buttermilk's acidity is neutralised by the powder's own acid, and there is no extra lift — but the moisture and tenderness remain.

Can I use buttermilk instead of eggs in a savoury bake?

Yes — buttermilk is excellent in savoury baking. It works in soda bread, biscuits, scones, cornbread and savoury muffins, where its tang suits cheese, herbs and vegetables. It does not work in pastry, where the egg's protein is structural, or in a quiche, where the egg is the main ingredient. For a cheese scone, replacing the egg with buttermilk gives a tender, tangy result.

Related links