Milk kefir can be made from kefir grains, or from a powdered starter. Here's how to make it from kefir grains.
When you receive your grains
If your grains have been stored in the fridge or freezer for a while or someone has posted them to you, they'll need some preparation before they make a good batch.
Put the grains into a jar with about ¼ of the normal amount of milk (eg. if you have 1 tablespoon of grains, use 1/2 cup milk). Leave out for 12 – 24 hours (depending on temperature), shaking or stirring from time to time. When the milk separates out (so that the thick curds are at the top, and the liquid whey is at the bottom), it’s fermented. Shake or stir well, so that the grains are easier to separate. Pour the mixture into a non-metallic strainer, with a jug underneath. Throw away the milk.
Repeat this washing and throwing away a second time.
After that they will make great kefir on the third batch.
Types of milk
Raw milk is best, but pasteurised works also. Avoid homogenised or ultra heat-treated milk.
If you can get milk from Jersey cows, it will be very high in cream, which makes delicious kefir. If your milk is lower in fat, you can add some extra cream to it, if you like.
Cow’s milk is usually used, but you can also kefir goat’s milk, coconut milk and other liquids. When you use cow’s milk, the grains will grow each time you use them. But with other milks they won’t grow, and may eventually stop working.
You can also get water kefir grains, which feed on glucose instead of lactose. Or you can convert milk grains to water grains, though they won’t then grow. They can then be used to make fermented fruit juice drinks. (But that’s another post!)
Ratio of milk to grains
Each tablespoon of grains will ferment about ½ a litre (2 cups) of milk. Each time, your grains will grow a little. So you can increase the amount of milk you’re fermenting, or separate the grains into two batches. Store the spares, or share them. (Detailed instructions for shipping grains are available on request).
Making the kefir
Kefir is much more “forgiving” than yoghurt, as it isn’t temperature sensitive. It will ferment in about 7 days in the fridge, or in 12 hours to 2 days in a warm place (18-25C). The most popular way seems to be to keep in the fridge for 24 hours (or more) then leave on the bench for about 24 hours.
Place milk and optional cream in a clean wide-mouth jar. Ceramic is best, but glass will do. Add kefir grains, stir or shake well and cover loosely with a cloth or with the jar lid, placed loosely on top. Stir or shake vigorously occasionally to redistribute the grains. Every time you stir, taste the kefir. When it achieves a tartness to your liking, the kefir is ready. The kefir may also become thick and effervescent, depending on the temperature, incubation time and the amount of curds you use. (If you’re having trouble telling when it’s ready, I consider it ready when the mixture separates out. But that will depend on how tart you like it.)
Pour the kefir through a strainer into another jar to remove the grains. Store in refrigerator. If you have enough milk for a new batch, start it straight away. Keep in the fridge for up to a week, taking it out about 24 hours before you need it, to finish the fermenting. Otherwise, store grains in a small jar in some fresh milk. Grains may be stored in the refrigerator several weeks, but change the milk every few days. If you don’t have any milk, store them in filtered water, but they won’t keep as long.
Note: some people rinse their grains in water before starting a new batch. This isn’t necessary, and the grains will grow more quickly if you don’t rinse.
Check out Dom’s kefir “insite” http://users.chariot.net.au/~dna/kefirpage.html#what's-kefir for more information and recipes.