Water kefir
Milk kefir
Kombucha
Ginger beer
Kefir duo
Kefir and kombucha
Starter kit
RennetYoghurt is made in the warmth, with a few carefully chosen lactic acid bacteria: it is thick, mild and eaten with a spoon. Kefir is made at room temperature, with live grains that hold both bacteria and yeasts: it is runnier and livelier, with a yeasty note and sometimes a faint prickle. Kefir grains can be reused indefinitely, 20 g for 1 litre of whole milk in 24 hours at 20 to 25°C. Both are delicious, and they work very well together in the kitchen.
Two ways of fermenting milk
Yoghurt is the work of a few specific lactic acid bacteria that like it warm. You add a spoonful of natural yoghurt or a starter to warm milk, then keep it warm for a few hours, in a yoghurt maker, a barely warm oven or a pot wrapped in towels. The milk sets in one solid mass and then goes into the fridge. For the next batch you start from a pot of the last one, and every so often from a fresh starter.
Milk kefir comes from grains: small, soft white clusters that look like cauliflower florets. They hold a partnership of lactic acid bacteria and yeasts. You drop them into milk at room temperature, cover with a tea towel, and the next day you strain. The kefir goes into the fridge and the grains go straight back into fresh milk. They grow over the weeks and do not wear out. How they work and why they have been handed down for so long is covered in What are milk kefir grains?
So the two follow different logic: yoghurt needs a bit of warmth and equipment, kefir needs a daily habit of two minutes.
The comparison at a glance
| Milk kefir | Yoghurt | |
|---|---|---|
| What ferments it | Live grains: bacteria and yeasts | A few lactic acid bacteria |
| Temperature | Room temperature, 20 to 25°C | Gentle warmth, yoghurt maker or warm oven |
| Time | About 24 hours | A few hours in the warmth |
| Kit | Jar, tea towel, sieve | Pots and a source of heat |
| Texture | From pourable to thick and creamy | Set, eaten with a spoon |
| Taste | Fresh, tangy, a yeasty note | Mild, milky, gently sour |
| Fizz | Sometimes a faint prickle | None |
| Next batch | The same grains, over and over | A pot from the last batch or a fresh starter |
The taste: two different kinds of sour
Taste them one after the other, at the same temperature, and the difference jumps out. Natural yoghurt is round and milky, its sourness comes in gently and leaves a creamy impression. It goes along with things without taking over, which is why it turns up in so many desserts.
Kefir is livelier. Its sourness is more upfront, its yeasts give it a note that recalls bread dough or a sweet cider, and it sometimes tingles very slightly on the tongue. Its taste also shifts more from day to day: strained early, it is mild and almost creamy; given a few more hours, it turns sharper and more aromatic. If you have ever baked scones with buttermilk, you will feel at home quickly, as Kefir or buttermilk? explains.
The milk matters a lot for both. Whole milk gives a rounder kefir and a creamier yoghurt. Goat's milk gives both a more pronounced flavour.
Texture, and how to control it
A yoghurt is set: it stands up on the spoon. Kefir sits somewhere between milk and a drinking yoghurt. It pours, it coats, and you decide how thick it gets.
- Thicker: let it ferment a little longer, or use a few more grains for the same amount of milk.
- Runnier: strain earlier, or stir in a little milk.
- Spoonable: strain the finished kefir overnight in a fine cloth in the fridge. You get a firm, silky kefir cheese, close to a Greek-style yoghurt. The method is in strained kefir cheese, lovely on hot buttered toast.
Every way of playing with texture is gathered in Milk kefir too thin or too thick.
In the kitchen: which stands in for which?
Good news: in most recipes one takes the other's place without any trouble. Just keep the texture in mind.
| Recipe | With kefir | With yoghurt |
|---|---|---|
| Cakes and muffins | Same quantity as yoghurt: a lighter, airier crumb | The classic, moist and dense |
| Pancakes | Part of the milk swapped for kefir: soft, fluffy pancakes | Thicker batter, needs thinning |
| Cold sauce | Pourable, ideal for drizzling | Thick, ideal for dipping |
| Overnight oats | The oats soak it up nicely | More compact, thin with a little milk |
| Smoothie | Blends easily | Makes a thicker smoothie |
| Marinade | Coats and tenderises chicken and lamb | Clings better to the meat, tandoori style |
For Pancake Day, kefir in the batter gives a soft, slightly tangy pancake. For a quick dip, the kefir cucumber dip is ready in five minutes; if you want it as thick as a tzatziki, use strained kefir or half kefir, half yoghurt. In the morning, kefir overnight oats are waiting for you in the fridge, a cold cousin of the bowl of porridge.
Day to day: two different rhythms
Homemade yoghurt is made in runs: you set six or eight pots at once, once or twice a week, and forget about it until the next batch. That is handy if you like pots ready to grab for a lunchbox.
Kefir runs on a daily rhythm. A jar is always on the go on the worktop; you strain and add fresh milk every day, often in the evening. In return it needs no machine and no heat source, and the grains stay with you for years. If you go away for a few days, they wait in the fridge in fresh milk. The full routine is in How to make milk kefir.
Which should you choose?
If you love set textures, desserts in pots and a mild milky flavour, yoghurt is still a fine companion. If you want a fermented milk to drink, livelier, that you keep going day by day without any machine, kefir is for you. And nothing stops you having both: plenty of our customers keep their yoghurt for dessert and pour their kefir over the morning muesli.
To get started, our live milk kefir grains come in 10 g (half a litre a day) or 20 g (1 litre a day), from £14, with step-by-step instructions. Every step, from choosing the milk to caring for the grains, is on the milk kefir page.