Clockwise from rear: Sparkling Elderflower water kefir, water kefir grains in sugar solution, kefir cheese, kefir grains in milk.

If kefir didn’t naturally exist the chances of any crazy scientist inventing the stuff would be pretty unlikely. It’s just too weird.

A wholly unlikely symbiotic structure consisting of bacteria, yeasts, protein, sugar and lipids, kefir grains possess a strange and slightly unappetising, cauliflower-like appearance, their size and shape changing as they feed and grow. Search the web and more often than not you’ll stumble upon websites with more than a whiff of incense about them. Health nuts and Woodstock refugees seem strangely attracted to the stuff. Consequently, instructions for caring for kefir grains often verge on the superstitious.

It’s thought that the the shepherds of the North Caucasus were the first to make use of kefir, placing the grains in fresh milk as a way to preserve it, the inoculation transforming it into a refreshing beverage in the process. Left to its own devices, kefir will feed on the lactose in the milk, the process souring it as with yoghurt culture, but with the yeasts also producing carbon dioxide and a small amount of alcohol (typically 1%). As with a sourdough yeast starter, the level of tartness and the yeast activity can be controlled to some extent by temperature and the amount of ‘food’ available.

While kefir can be used to leaven bread, and the curds produced by kefir do make an interesting alternative to fresh milk cheese curds, the drink itself is something of an acquired taste. A milky drink that’s fizzy and yeasty is just too freaky for many Western palates.

Water kefir, though, that’s a different story.  Where regular kefir originates with flora from a sheep’s intestines, this stuff is thought to have first been discovered on the leaves of a type of Mexican cactus. Thriving in sugared water rather than milk and with a slightly different bacterial and yeast strain makeup, water kefir – also known as Japanese water crystals, African bees or Tibicos – can be used to produce drinks that Westerners will lap up. Even without any additional flavouring, water kefir drinks pack a tang not unlike that of ginger beer (the original ‘Ginger Beer Plant’ is actually another bacteria-and-yeast symbiotic blend, and water kefir was also traditionally also used as an alternative).

Unfortunately kefir d’acqua seems to be the runt of the litter. Keeping it healthy involves regular feeds, as well as just the right acidity and mineral levels. Here’s a simple guide based on my experiences:

Basic water kefir drink technique

1. Place your grains in water – a couple of spoonfuls of grain will happily work their magic on a good litre of water. If mineral water isn’t available (or is too costly in the long run), try a mix of tap and filtered. Try adding a touch of calcium chloride  if your grains are looking overly ‘cloudy’ (but not too much, as it can cause the liquid to become unpleasantly syrupy), and throw in half an unwaxed lemon to keep the pH level just right. Don’t add lemon or any other fruit juice as this will tip the acidity too far. You can, however, add fairly acid-neutral flavourings such as crushed ginger root.

2. Be sure to keep it in a container that will let the excess carbon dioxide escape. Leave at room temperature to ferment for a day, add another tablespoon or two of sugar and give it another 24 hours.

3. Sieve the contents, decanting the liquid into a bottle along with any extra flavourings. The kefir grains can be re-used again (as can the lemon for a few more runs).

4. You can drink your kefir beverage at this point, but if you really want to get busy with the fizzy, place it in a sturdy flip-top glass bottle. Add a touch more sugar, seal the bottle and ferment for another 24 hours. Refrigerate ready for use.

You can find kefir and water kefir sellers on ebay, or ask a friend to share some of their ever-multiplying grain stash. Just watch out for the tie-dye.