A 500ml glass jar / kilner jar
A handful of kefir grains
Organic cow/goats milk (ideally UHT)
Put the kefir grains in the glass jar, then fill it with the milk about 2/3 or so full. Cover the jar with a cloth or put the lid on the jar (loosley so as to let any gas escape.)
Let the contents stand at room temperature for approx. 24 hours depending on your taste. 48 hours will make a thicker, sourer kefir, 12 hours a thinner, sweeter kefir. The temperature will effect how quickly the culture works, so during the warm summer months the kefir will ferment faster.
When it's ready strain the kefir into a bowl or jug, ready for drinking. While it's fermenting the kefir grains will float to the top of the milk along with any cream. It's a good idea to stir it gently with a wooden spoon to mix up the solids and liquids to make it easier to strain. Giving it a good stir will distribute the kefiran in the kefir and it contributes to the thickness of the finished kefir.
After straining, the grains are placed straight back into a clean jar without washing them first. More milk is added to the grains to make the next batch. Essentially, that's it.
A cooler temperature slows the fermentation down and makes a thicker kefir too. Some people like to ferment their kefir in the fridge, leaving it for 5 days or more to compensate for the much slower fermentation process.
Storing the Culture:
After each batch you'll have a few more grains as the culture grows. Eventually you'll have quite a large batch of grains (more than necessary) and they'll speed up your fermentation time although they will make the Kefir taste stronger.
Spare culture can be separated and stored for a time in a jar in the fridge with some milk. The fermentation will slow right down and you can store them for a few weeks this way or a few months if you store them in water. Its a good idea to rotate them with the grains you're using for your regular kefir making so that they get a chance to warm up and restore vitality to their microflora. The grains can safely be stored in suspended animation, in your freezer or you could pass spare culture on to a friend. A wonderful, life-enhancing gift.
Storing the Kefir Drink:
Store the kefir in a glass jar in the fridge. The kefir will keep a long time in the fridge. Add new batches of kefir to the storage jar as they are made and give it a shake to mix them.
The Kefir grains (pictured above) are available for free here