Water kefir, milk kefir and homemade yoghurt: differences and how to start
TUREFF• •0
Kefir and yoghurt are both cultured drinks or foods, but they are made in different ways with different microbes. Milk kefir and water kefir sound like two versions of the same thing, yet they use different cultures that cannot simply be swapped. This guide explains the differences and gives a simple starting method for each.
The quick comparison
- Yoghurt: milk fermented by a small number of bacteria, kept warm for several hours. Thick, mild to tangy.
- Milk kefir: milk fermented at room temperature by kefir grains, a mix of bacteria and yeasts. Thinner than yoghurt, sour, sometimes a little fizzy.
- Water kefir: sugar water (often with dried fruit) fermented at room temperature by water kefir grains. Dairy-free, light and fizzy, more like a home-made soft drink.
The "grains" are not cereal grains. They are small, gelatinous clusters of bacteria and yeasts. Milk kefir grains look like little pieces of cauliflower; water kefir grains are translucent crystals. Each kind is adapted to its own food, so keep milk grains in milk and water grains in sugar water.
Milk kefir
- Put the grains in a clean glass jar and pour over fresh milk. Many people start with a tablespoon or so of grains to a few hundred millilitres of milk.
- Cover with a cloth or a loosely fitted lid.
- Leave at room temperature for roughly a day, until the milk has thickened and smells sour.
- Strain out the grains with a plastic or stainless steel sieve and start the next batch with fresh milk.
- Refrigerate the kefir.
Notes:
- If it separates into curds and whey, it has gone a little far; it is usually still fine, just more sour. Use fewer grains or a shorter time.
- To take a break, put the grains in fresh milk in the fridge, which slows them right down. Revive with a couple of batches at room temperature.
- The grains grow over time. Share the extra or compost it.
Water kefir
- Dissolve sugar in water in a clean glass jar. Plain white or light brown sugar is the usual choice.
- Add the water kefir grains, and optionally a piece of dried fruit or a slice of lemon.
- Cover with a cloth and leave at room temperature for a day or two.
- Strain out the grains and start a new batch.
- For more fizz, bottle the liquid in pressure-safe bottles, add a little fruit or juice and leave sealed for a day, then refrigerate.
Notes:
- Bottles can build up a lot of pressure. Open carefully, and move them to the fridge once fizzy.
- Water quality can affect the grains; if they stop growing or turn slimy, try a different water source.
- Like kombucha, water kefir contains a small amount of alcohol, more if it is fermented for longer.
Yoghurt
Yoghurt is started with a few spoonfuls of plain live yoghurt or a dried culture.
- Heat the milk to about 82 degrees C (180 F) and hold it there for a few minutes. This changes the milk proteins, which gives a thicker set, and kills competing microbes.
- Cool to about 43 to 46 degrees C (110 to 115 F). Any hotter and you kill the culture.
- Add starter: stir in a few spoonfuls of plain yoghurt with live cultures.
- Incubate at around 43 degrees C (110 F), covered and undisturbed, for roughly 6 to 12 hours. An oven with only the light on, a vacuum flask, a slow cooker on warm, a yoghurt maker or a multicooker all work.
- Chill once it has set. Longer incubation gives a tangier, firmer yoghurt.
- For thick, strained yoghurt, drain it in a cloth-lined sieve in the fridge.
Save a few spoonfuls from each batch to start the next, but buy fresh starter now and then if the batches get weaker.
Safety notes
- Use clean jars and utensils, and fresh milk.
- Throw out anything with fuzzy or coloured mould, a pink or orange tint, or a rotten smell.
- If you are pregnant or have a weakened immune system, avoid raw (unpasteurised) milk, and ask your doctor about home-fermented drinks.
- Pasteurised milk gives the most predictable results.
Which do you make, and how long do you leave yours? Share your methods and questions in the comments.