How to make buttermilk from milk (2026)
Quick Answer
To make a simple buttermilk substitute from milk, add an acid such as lemon juice or white vinegar to the milk, stir, then leave it to stand until it looks slightly thickened and a little curdled. It is ready when the milk has soured enough to react like buttermilk in baking, though it is not the same as traditional cultured buttermilk.
Overview
If a recipe calls for buttermilk and you only have ordinary milk, the easiest fix is to sour the milk with a small amount of food-safe acid. This works well for baking because the acidity helps activate bicarbonate of soda and can also slightly tenderise batters and doughs. The usual home method is simple: put the acid in first, add the milk, stir, and let it sit briefly so the texture and acidity develop. You are looking for milk that is a bit thicker than plain milk and may show tiny flecks or a lightly curdled appearance; that is a sign the acid is doing its job. This homemade version is best used as a direct stand-in for recipes such as pancakes, soda bread, cakes and muffins. It is less suitable where the flavour and texture of true cultured buttermilk are central, such as dressings or drinking. If you happen to have plain yoghurt, kefir or cultured buttermilk, those are often closer substitutes. Use fresh milk, clean utensils and a clean container, and make the substitute shortly before cooking for the most reliable result.
Who this is for
Home cooks and bakers who need a quick substitute for buttermilk using ordinary milk.
What you’ll need
- milk
- lemon juice or white vinegar
- measuring jug or cup
- spoon
Before you start
Check what your recipe needs the buttermilk for. This substitute is most reliable in baking and other cooked recipes. Use fresh milk that smells normal and has not passed its use-by date, and make sure your acid ingredient is food-safe and plain rather than flavoured.
Step-by-step
- 1
Choose your acid
Decide whether to use lemon juice or white vinegar. Either can sour milk effectively for a baking substitute.
Why: The acid is what changes the milk so it behaves more like buttermilk in a recipe, especially where raising agents are involved.
- 2
Put the acid in the measuring jug first
Add the acid to your jug or cup before the milk. Then pour in enough milk to reach the total amount of buttermilk your recipe calls for.
Why: Adding the acid first makes it easier to end up with the right final volume rather than adding extra liquid by mistake.
- 3
Stir gently
Stir the milk and acid together until fully combined. Do not whisk aggressively; a simple stir is enough.
Why: Even mixing helps the acid contact the milk properly so it sours evenly.
- 4
Leave it to stand
Set the mixture aside for a short time at room temperature until it thickens slightly and may show a faintly curdled look.
Why: The resting time allows the acid to react with the milk proteins, which gives the substitute its characteristic texture and acidity.
- 5
Check that it looks right
Use it when it looks a little thicker than plain milk and no longer appears completely smooth. Small curdled flecks are normal.
Why: That change shows the milk has soured enough to perform more like buttermilk in cooking.
- 6
Use it in your recipe
Stir once more, then add it to the recipe as the full amount of buttermilk required. If your recipe is sensitive to texture, strain only if there are large lumps rather than fine specks.
Why: A final stir redistributes any solids so the acidity is consistent throughout the mixture.
Why this works
Buttermilk is acidic. When you acidify milk, you lower its pH and lightly curdle some of its proteins, giving a similar acidity and some of the same functional behaviour in recipes. In baking, that acidity reacts with bicarbonate of soda to help with lift and can contribute to a more tender crumb.
Common mistakes to avoid
- Using old or nearly spoiled milk instead of fresh milk
- Adding acid on top of a full measure of milk and ending up with too much liquid
- Using this quick substitute for recipes where true cultured buttermilk flavour is essential
- Not letting the mixture stand long enough to sour properly
Troubleshooting
The milk still looks completely plain and thin
Stir again and give it a little more standing time. Make sure you used a suitable acid such as lemon juice or white vinegar.
There are larger lumps than expected
Stir gently to break them up. If the recipe needs a smoother liquid, strain out only the larger curds and use the rest.
The recipe tastes slightly sharp
Next time use a milder acid option or choose cultured dairy such as plain yoghurt thinned with milk if the recipe would suit it better.
Baked goods did not rise well
Check that your raising agent is still active and that the recipe actually relies on an acidic dairy ingredient. Also avoid letting the batter sit too long before baking.
Compare your options
Milk plus lemon juice or white vinegar
Best for: Quick baking substitute
Pros: Fast, uses common ingredients, gives the acidity many recipes need
Cons: Not identical to cultured buttermilk in flavour or thickness
Plain yoghurt thinned with milk
Best for: Recipes needing a closer texture
Pros: Often thicker and tangier, closer to cultured dairy
Cons: May need adjusting to reach a pourable consistency
Kefir
Best for: Closest ready-made substitute in many recipes
Pros: Naturally cultured and tangy, good texture
Cons: Not always on hand and flavour may be stronger
Cultured buttermilk
Best for: Recipes where buttermilk flavour matters
Pros: Most accurate taste and behaviour
Cons: Less convenient if you do not already have it
| Option | Best for | Pros | Cons |
|---|---|---|---|
| Milk plus lemon juice or white vinegar | Quick baking substitute | Fast, uses common ingredients, gives the acidity many recipes need | Not identical to cultured buttermilk in flavour or thickness |
| Plain yoghurt thinned with milk | Recipes needing a closer texture | Often thicker and tangier, closer to cultured dairy | May need adjusting to reach a pourable consistency |
| Kefir | Closest ready-made substitute in many recipes | Naturally cultured and tangy, good texture | Not always on hand and flavour may be stronger |
| Cultured buttermilk | Recipes where buttermilk flavour matters | Most accurate taste and behaviour | Less convenient if you do not already have it |
Alternatives
- Use plain yoghurt loosened with a little milk
- Use kefir as a direct substitute if the recipe allows
- Buy cultured buttermilk when flavour and authenticity matter
Pro tips
- Make the substitute just before you mix your batter or dough
- Whole, semi-skimmed or skimmed milk can work, though richer milk may give a fuller result
- If using it in baking, have the oven or pan ready so you can cook soon after mixing
- A slightly curdled appearance is expected and not a sign of failure
Safety notes
- Use only fresh milk and discard anything with an off smell or abnormal colour before adding acid
- Use clean utensils and a clean container to reduce contamination
- Do not rely on acidified milk to make unsafe milk safe
- Store any leftover substitute in the fridge and use promptly
What this guide does not cover: This guide covers a quick home substitute made by acidifying milk, not the full process for producing traditional or cultured buttermilk.
Cost considerations
This is usually a low-cost substitute because it uses ingredients many kitchens already have. If you bake often, keeping either cultured buttermilk, plain yoghurt or kefir may be more convenient than making a substitute each time.
Frequently asked questions
Is homemade buttermilk the same as shop-bought buttermilk?+
No. Milk soured with lemon juice or vinegar is a practical substitute, mainly for cooking and baking. Traditional cultured buttermilk has a different flavour, texture and fermentation process.
Can I use any kind of milk?+
Most common dairy milks can work for a basic substitute. The exact richness and texture will vary with the fat content.
Can I use this for frying chicken or salad dressing?+
You can use it in some cooked applications, but for dressings or recipes where buttermilk is a main flavour, cultured buttermilk, kefir or plain yoghurt is usually better.
Why does the milk look curdled?+
That is expected. The acid causes some of the milk proteins to clump slightly, which is part of what makes it behave more like buttermilk.
Can I make true buttermilk from milk at home?+
You can make cultured dairy at home, but that is a different process from this quick substitute and requires a proper culture and careful food-safety handling.
The basic method for making a quick buttermilk substitute from milk changes very little over time.