Use kefir instead of buttermilk at 1:1. Buttermilk and kefir do similar work in a recipe, but they are not identical, and the ratio is what makes the swap succeed. This guide gives the exact ratio, an equivalence table for every amount you will need, what changes in the finished dish, and when you should not make the swap at all. All ratios on this page come from the CookScale substitution data, and every result is approximate; taste the dish before serving, and adjust the seasoning if the swap changes the flavour.
Buttermilk to Kefir: equivalence table
The table below scales the ratio — 1:1 — to every amount you will need, from a quarter of a cup up to three cups. Use the row that matches your recipe, and do not guess the scaling in your head, because a small error in the ratio grows with the size of the recipe.
| Buttermilk needed | Kefir |
|---|---|
| 1/4 cup | 1/4 cup |
| 1/2 cup | 1/2 cup |
| 1 cup | 1 cup |
| 2 cups | 2 cups |
| 3 cups | 3 cups |
When a recipe calls for an amount that is not in the table, scale the ratio proportionally: work out how many cups of buttermilk the recipe needs, then multiply the ratio by that number. For a single cup, the ratio is exactly as stated; for half a cup, halve it; for two cups, double it. Keep the recipe scaler open while you cook, and you can scale the whole recipe, including the substitution, in one step.
What changes when you use kefir instead of buttermilk
Kefir is the closest substitute for buttermilk in both texture and flavour, because it is a cultured, tangy milk drink with a similar thickness. The main difference is the tang: kefir is slightly sharper and more complex than buttermilk, because it is fermented with a wider range of cultures, and some people notice a faint yeasty note. In baking, the difference is barely noticeable: the acid activates the baking soda in exactly the same way, the crumb is just as tender, and the rise is the same. In a marinade, kefir works just as well as buttermilk, because the acid tenderises the meat in the same way. In a dressing, kefir gives a thinner, more pourable result, which suits a salad dressing, and the flavour is a little sharper, so taste it before serving.
When not to substitute buttermilk with kefir
Do not use plain milk — without acid, baking soda will not activate and the bake can taste soapy. That rule is the most important part of this page, because a substitution that works in one recipe can fail badly in another. Buttermilk does a specific job in each recipe, and the swap only works when the substitute can do the same job. In a recipe where buttermilk is the main structure — where it holds the bake together, or where its flavour is the point of the dish — the substitute will not do, and it is better to wait until you have the real ingredient, or to choose a different recipe. In a recipe where buttermilk is a supporting ingredient, where it adds moisture, richness or flavour but does not carry the dish, the swap usually works well. The test is simple: if removing the buttermilk would ruin the recipe, do not substitute it; if the recipe would still work without it, the substitute is probably safe.
Why this swap works
The acid in buttermilk activates baking soda and tenderises crumb; any acidic milk works the same way. That is the principle behind the swap: the substitute does the same chemical or structural job as the original, even though it looks and tastes different. The acid in an acidic substitute activates baking soda, the fat in a fatty substitute shortens a dough, and the liquid in a liquid substitute hydrates the flour. When the substitute does the same job, the swap works; when it does a different job, the swap fails. The ratio on this page is the amount that makes the substitute do the same job as the original, and it is worth following exactly, rather than guessing, because a small error in the ratio changes the job the substitute does.
Worked examples: buttermilk to kefir in real recipes
1. Kefir pancakes for a quick breakfast
A stack of pancakes for four needs a cup of buttermilk, so use a cup of plain kefir, measured exactly the same way. The kefir gives the pancakes the same tang and the same lift, because its acid activates the baking powder, and the pancakes turn out light and fluffy. Shake the bottle well before pouring, pour the kefir into the batter exactly where the buttermilk would have gone, and cook the pancakes over a medium heat.
2. A kefir marinade for fried chicken
A fried chicken marinade for four needs a cup of buttermilk, so use a cup of plain kefir instead. The kefir tenderises the chicken in the same way as buttermilk, because the acid breaks down the proteins, and its thickness helps the marinade cling to the chicken. Marinate the chicken for at least an hour, or overnight for the best result, and turn it halfway through to coat it evenly.
3. A kefir dressing for a green salad
A salad dressing for four needs a cup of buttermilk, so use a cup of plain kefir, measured exactly the same way. The kefir gives the dressing a thinner, more pourable texture than buttermilk, which suits a green salad, and the flavour is a little sharper, so taste it before serving and add a pinch of sugar if the tang is too strong. Whisk the kefir with the herbs and seasonings, and serve the dressing on the side.
How to make the swap
Measure the kefir cup for cup, exactly as you would the buttermilk, and use it in the same place in the recipe. No other change is needed, and no thinning is required, because kefir has almost the same thickness as buttermilk. Use plain kefir, not flavoured, because flavoured kefir adds sugar and flavour the recipe did not ask for. Shake the bottle well before pouring, because kefir can separate and the last glass is thicker than the first. For a biscuit or a scone, use the kefir cold, straight from the fridge, so the butter stays cold in the dough. For a marinade, the kefir should be at room temperature, so it coats the meat evenly.
Common mistakes
The most common mistake is using flavoured kefir, which adds sugar and flavour the recipe did not ask for and can make a savoury dish taste odd. Use plain kefir. The second mistake is shaking the bottle and then pouring it straight away, before the kefir has settled; let it sit for a moment, or the first pour will be thin and the last pour thick. The third mistake is heating kefir too quickly in a sauce, which makes it split and turn grainy; keep the heat low and stir constantly. Finally, do not use kefir in a recipe where the mildness of buttermilk matters, such as a delicate cake, because kefir is slightly sharper and the difference can be noticeable.
Frequently asked questions
Can I substitute kefir for buttermilk 1:1?
Yes, kefir replaces buttermilk cup for cup, with no other change needed. Kefir has almost the same thickness as buttermilk, so no thinning is required, and the acid activates baking soda in exactly the same way. Use plain kefir, not flavoured, because flavoured kefir adds sugar and flavour the recipe did not ask for.
Is kefir the same as buttermilk?
No, but they are very close. Both are cultured, tangy milk products, but kefir is fermented with a wider range of cultures, so it tastes slightly sharper and more complex, with a faint yeasty note. Buttermilk is milder and creamier. In baking, the difference is barely noticeable, and kefir is the closest substitute you can buy.
Does kefir activate baking soda like buttermilk?
Yes. Kefir is acidic, just like buttermilk, so it activates baking soda in exactly the same way, giving the bake its rise and its tender crumb. The acid in kefir is what makes it such a good substitute, and the bake will rise just as well as it would with buttermilk.
Can I use flavoured kefir instead of buttermilk?
It is better not to. Flavoured kefir adds sugar and flavour the recipe did not ask for, which can make a savoury dish taste odd and a cake too sweet. Use plain kefir, and add your own flavourings separately, so you control the taste.
Can I use kefir in a buttermilk marinade?
Yes, and it works very well. The acid in kefir tenderises the meat in the same way as buttermilk, and its thickness helps the marinade cling to the chicken. Marinate the meat for at least an hour, or overnight for the best result, and turn it halfway through to coat it evenly.