Kefir substitutes

Cultured low-fat milk with almost the same thickness and almost the same acidity as kefir, and the single best swap in baking.

Best for

pancakes and waffles, quick breads and muffins, soda bread, marinades, salad dressings, cold soups

So close that most bakers use them interchangeably without comment. Kefir has a slightly more complex, faintly yeasty and champagne-like edge from its mixed bacteria and yeasts, and buttermilk tastes cleaner and simply sour, so a pancake made with buttermilk is a touch less interesting on the finish and no worse for it. Acidity is comparable, which is the part that matters for lift. Buttermilk carries no live yeast, so it will not fizz.

The pantry version, using yogurt for the tang and cultures and milk to bring it back to a pourable consistency.

Best for

baking, smoothies, marinades, dressings, drinking

Almost as good as buttermilk and better if the yogurt is a live-culture one, because you keep some of the point of using kefir in the first place. Whisk properly, since lumps of yogurt will not disperse in a batter and show up as pale streaks. Yogurt is thicker and slightly less sour than kefir, so if the result tastes flat add a teaspoon of lemon juice. Greek yogurt needs more milk, closer to a 2:1 yogurt-to-milk ratio.

The classic emergency acid trick, which handles the chemistry of kefir without any of the fermentation.

Best for

pancakes, muffins and quick breads, scones, cakes leavened with baking soda

Do this only for baking, and be clear about what it does and does not do. It supplies the acid that reacts with baking soda, so your rise is safe, and the milk supplies the liquid. What it does not supply is the thickness or the fermented depth, so a batter made this way is thinner and the finished bake tastes plainer and slightly less tangy. Whole milk works better than skim. It will look curdled and separated after ten minutes, which is correct.

The Swedish, Danish and Finnish soured milks from the same family as kefir, sold in every Nordic supermarket.

Best for

drinking, breakfast with muesli, baking, cold soups, Nordic recipes that call for soured milk

Functionally the same ingredient with a different culture. Filmjolk and viili are thicker and gentler, with viili in particular being noticeably ropy and mild, while ymer is thicker again and closer to a thin yogurt. None of them are fizzy the way a well-fermented kefir can be. If a Nordic recipe names any of these and you have kefir, or the other way round, use it directly.

Cultured cream let down with milk, for when the recipe wants tang and richness together.

Best for

cakes and rich batters, sauces, cold soups, dressings

Tangy and pourable, but far fattier than kefir, so a cake comes out richer and more tender and a dressing comes out heavier and less refreshing. The acidity is lower than kefir's, so if baking soda is the only leavener add half a teaspoon of lemon juice to be safe. It also splits less readily in heat than kefir does, which makes it the better option in a warm sauce.

Coconut, oat or soy kefir, or the sugar-water ferment sold as water kefir, for dairy-free cooking.

Best for

dairy-free baking, drinking, smoothies, vegan dressings

Coconut and oat kefirs work well in baking, since they carry both the acid and roughly the right viscosity. Water kefir is much thinner and considerably less acidic, so it is fine to drink but a poor choice in a batter, where it will not thicken anything or reliably trigger baking soda. If you must use water kefir in baking, add a teaspoon of lemon juice per cup and expect a looser batter.