Kefir is a fermented milk drink produced by a symbiotic culture of bacteria and yeasts (the kefir “grains”) rather than the pure bacterial cultures used to make yoghurt. The result contains a wider range of probiotic strains than yoghurt, has a thinner consistency, a pleasantly tart flavour, and a slight natural effervescence from the yeast activity. Making it at home requires kefir grains (available from health food stores, online, or from someone who already makes kefir and has spare grains), whole milk, and a glass jar. That’s everything.
Getting Kefir Grains
Kefir grains aren’t actually grains. They’re small, springy clusters of bacteria and yeast that look a bit like tiny cauliflower florets. They’re alive, and when they’re looked after they grow and multiply, so you won’t run out. Grains that have been dried or frozen can be slow to wake up. Use them as normal and expect the first few batches to be thin or slow. Frozen grains can take up to three months to make consistently good kefir.
The Basic Process
Put 2 to 3 tablespoons (about 50 g) of kefir grains in a clean glass jar and pour in 500 ml of full-fat milk. If you only have a tablespoon or two of grains, start with about a cup of milk and build up as they grow. Cover the jar with a piece of muslin held on with a rubber band and leave it somewhere dark at room temperature for 12 to 24 hours. It ferments faster in warm weather and slower in cool. Keep it out of rooms hotter than about 32°C, where the milk can spoil before the grains have done their work.
When it’s ready, tip everything into a sieve set over a bowl and gently shake the sieve so the kefir drains through, leaving the grains behind. Some kefir makers only use plastic sieves and wooden or plastic spoons, worried that metal weakens the grains. Others happily use stainless steel. Pour the kefir into a clean bottle or jar and keep it in the fridge for up to a week. Put the grains straight into a clean jar with fresh milk to start the next batch. There’s no need to rinse them.
What to Do with Kefir
Drink it straight – many people do, and the flavour is an acquired taste that most find pleasant within a few weeks. Use it in smoothies in place of milk or yoghurt. Make kefir pancakes (identical to the yoghurt pancakes recipe, just substituting kefir for yoghurt). Use as a marinade for chicken or meat in the same way as yoghurt. Make kefir salad dressing with herbs, garlic, and lemon. Freeze into kefir ice blocks for a probiotic treat.
Caring for Your Grains
Healthy grains grow over time, and after a few weeks you’ll have more than you need for one batch. Make a bigger batch, start a second jar, or give some to a friend who wants to start. For a short break, leave the grains covered in milk in a lidded jar in the fridge, where they slow right down. If it’s been more than about 4 days, tip out that milk, strain the grains and start a fresh batch. For a longer break, grains can be frozen: rinse them, pat them dry on a clean cloth, coat them lightly in milk powder and freeze them in a double bag. Expect frozen grains to be slow when they come back.
Kefir grain fermentation is one of the most ancient food technologies in existence – cultures across the Caucasus and Central Asia have been making kefir for thousands of years. The grains themselves are passed between families and communities and can be maintained indefinitely with proper care. Starting a kefir habit means you’re taking on a small living culture that, with a few minutes of attention every couple of days, will produce an endless supply of one of the most nutritionally dense fermented foods available.
Knowing When It’s Ready
Kefir is ready when it’s thicker than milk but still pourable, and smells fresh and sour, a bit like Greek-style yoghurt. It may be slightly fizzy. That usually takes 12 to 24 hours. Once you see it starting to separate into curds and whey, strain it. If it has gone further and formed firm curds, sit the sieve in the bowl of drained kefir and gently work the curds loose with a spoon, then lift the sieve and drain it again. The springy grains hold their shape while the curds break up. Next time, strain a little earlier.
Troubleshooting
The grains aren’t multiplying. Slow growth usually means the grains are still recovering from being dried or frozen, or they’re short of food. Give them fresh full-fat milk every batch and be patient. Grains that have been frozen can take up to three months to get back to full strength.
My kefir is too sour or too thin. Both come down to ferment time and temperature. Sour and thick means it went too long, so strain earlier. Thin and barely soured means it needs more time or a warmer spot. Adjust by a few hours at a time until you find the window that suits your kitchen.
My kitchen is very warm. Keep the jar somewhere dark and below about 32°C. Any hotter and the milk can spoil before the grains have cultured it. In a hot spell you can slow things down by leaving the jar to ferment in the fridge instead, where it takes longer.
Common Questions
Does kefir contain alcohol? A trace, yes. The yeast activity produces a very small amount of alcohol, usually well under one percent, similar to a ripe banana or a juice that has sat out. A longer or sealed second ferment lifts it slightly. For almost everyone this is negligible.
Is kefir suitable if I’m sensitive to lactose? Many people who struggle with milk tolerate kefir better, because the cultures consume much of the lactose during fermentation, and the longer it ferments the less remains. This is general guidance rather than medical advice, so go gently if you are unsure.
Can I use plant milk? The grains live on dairy milk, and ordinary full-fat supermarket milk is fine. They will ferment plant milks such as coconut, soy or almond, but they won’t grow in them, so give them a feed of dairy milk every couple of batches to keep them healthy.
How much should I drink? Start small, a quarter of a cup a day, and build up as your gut adjusts. Going hard from day one can leave you bloated. There is no need to drink large amounts to get the benefit.
Sources
The method on this page is adapted from Sharon Flynn’s milk kefir recipe from Ferment For Good, published by SBS Food and Emma Galloway’s guide to making kefir at home, published by Food52.
