What is kefir?

Kefir is one of the world's oldest fermented foods — a cultured dairy drink, traditionally made by fermenting milk with kefir grains. It is the living, tangy dairy that frozen kefir is made from. Here is what kefir actually is, how it is made, and how it differs from yogurt.

What kefir is

Kefir is a fermented, cultured dairy drink with roots in the Caucasus mountains, where it has been made for centuries. Where milk is simply milk, kefir is milk that has been transformed by live cultures — a fermentation that gives it a fresh, clean, slightly sour tang and a light, faintly effervescent character.

Poured from the bottle, good kefir is thinner than set yogurt and pleasantly drinkable. That tang is not sourness for its own sake — it is the signature of real fermentation, the same process that gives cultured dairy its depth of flavour. Because the cultures work through the milk as they ferment, kefir is also naturally lower in lactose than the milk it started as.

How kefir is made

Traditional kefir is made with kefir grains — and, despite the name, these are not cereal grains at all. They are small, living clusters of live cultures and milk proteins that look a little like soft cauliflower florets.

The grains are added to milk and left to ferment, usually for around a day at room temperature. During that time the live cultures in the grains feed on the milk, converting its lactose into lactic acid — the change that thickens the milk slightly, builds the tang, and creates kefir's gentle effervescence. Once the milk has cultured, the grains are strained out and reused for the next batch, so a single set of grains can make kefir again and again.

Kefir vs yogurt

Kefir and yogurt are close relatives — both are fermented, cultured dairy — but they are not the same thing. The differences come down to the cultures used, the texture, and the way each is made.

In short: kefir is fermented with a broader, more diverse range of cultures than yogurt. It is traditionally thinner and more effervescent where yogurt is thick and set, it ferments with grains rather than a smaller starter culture, and it is naturally lower in lactose than milk. Yogurt tends to be milder and denser; kefir is brighter, tangier and more lively on the palate.

From kefir to frozen kefir

Once you understand kefir, frozen kefir makes sense. Take that living, cultured dairy, strain it until it is thick and creamy, then freeze it gently, and you have frozen kefir — a cultured frozen dessert that keeps kefir's clean, tangy character but sets soft and light rather than dense like ice cream.

At Snowfall in Marylebone, that dessert is made with no added sugar — sweetened with stevia and erythritol instead. To see how the cultured drink becomes the dessert, step through how frozen kefir is made.

Frozen kefir is a dairy product and naturally contains a small amount of milk sugars. “No added sugar” means no sugars or sweetening foods are added; sweetness comes from stevia and erythritol.

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