Introduction to … Water Kefir (by Louis-Guy)

revised and expanded version 20230404a,
Machine Translated text (DeepL)

Equipment Required

  • A glass jar or wide-mouthed bottle (allowing you to put in and easily recover a slice of lemon and a fig), generally 0.5L to 1L for personal daily consumption
  • Paper towels (=sopalin for our friends across the border) with normal square cuts (not half rectangular cuts), or cheesecloth or equivalent cloth
  • Elastics


  • When storing kefir, use a glass bottle that can withstand the pressure.
  • Do NOT use a square glass vessel, the walls of which are too fragile in places. (Risk of explosion)
  • Use bottles with screw caps or flip-top caps.
  • Do NOT use friction caps (cork). Risk of injury if the cap bursts

Optional equipment

  • Scale 500 grams/0.01g (15 EUR sold online)
  • Funnel with filter to easily collect the beans

Ingredients Required

  • Fresh or recativised kefir grains
  • Organic lemon
  • Organic semi-dried figs
  • Water with low mineral content : not ‘spa reine’ (not enough mineral content) or ‘contrex’ (too much mineral content!)).
  • Organic light cane sugar (no sugars such as coconut sugar, arenga, brown candy sugar, etc. which contain too many minerals). White sugar can be used, but brings very little nutrients to the grains.

Optional ingredients

  • Dried hibiscus flowers
  • Eggshells with inner skin removed or Lithothamnion (crushed limestone rich in minerals from the cliffs)

Fermentation (in a wide-mouthed bottle or jar, measures for 0.5 litres)

  • 10-12 grams of kefir grains
  • 10-12 grams of organic cane sugar
  • 1 organic fig
  • 1 organic lemon slice with a little (max 1 cm) or no peel. The lemon is optional, but it is a source of acidity and mineral salts that are favourable for the beginning of the fermentation process.

Top up with low mineralized water to 0.5 litres

Stir immediately to dilute most of the sugar, so that the kefir does not stay in contact with sugar that is too pure (risk of osmotic bursting of the cell walls)

Close the bottle with a paper towel+ elastic, or possibly a lid/cap just placed so that the CO2 pressure can escape, or use a bottle with a “weak” seal.

Be careful, fruit flies are very fond of kefir, check the cap’s fixation in case of a paper towel closure, they even slip through the perforations of the pre-cuts…

Typical fermentation time: 24 to 36 hours at room temperature. The rise of the fig, full of CO2, is not a very reliable sign of the end of fermentation. It is better to precisely measure grains and sugar and temperature and time

Carbonation: (if you want it sparkling)

Remove grains, lemon, fig, put the grains in the fridge (see conservation) and/or take some for the next production, the surplus goes into conservation.

Transfer the kefir into a bottle that closes tightly and holds pressure, leaving at least 2-3 cm free at the top of the bottle so that the gas can build up and compress gradually (otherwise the pressure rises too quickly and carbonation stops without enough CO2 being dissolved).

The pressure build-up discourages fermentation and eventually stops it.
Optional: add 1 gram of sugar (in case the kefir has already consumed all the sugar)
Leave in sealed bottle at room temperature for 24 hours
Then put in the fridge after adding any seasoning. Carbonation continues but very slowly and then stops.


It is possible to add, for example, fruit, fruit juice, citrus peel, mint leaves, or hibiscus flower petals to give colour and flavour, but ideally you should wait until the end of carbonation and at least the end of fermentation before putting them in contact with the kefir, as this could otherwise inhibit fermentation (bactericidal effect).


When the grains grow optimally, the weight of the grains increases by 20 to 50% at each cycle depending on the health of the grains, sugar and fermentation time.

To give an idea, starting with 10 grams, considering a moderate daily growth of 20% of the grains, we would get a tub of grains (150 litres) after 53.74 days…

If the grains do not gain any weight from one production to the next (hence the interest of the precision scale), something is wrong. It is sometimes possible to revive the grains by adding occasionally (not every time, otherwise you basify too much) a knife tip of lithothamnion or pieces of eggshells to bring minerals.

Be careful, according to my experience, grains without food for more than 48 hours at room temperature start to die. The cellulose structure of the grains slowly disintegrates after several days but the microorganisms are often dead before the clear signs of grain disintegration.

Do not add other products before the kefir is finished (e.g. hibiscus flowers) as this often inhibits growth

The hotter the temperature, the quicker the fermentation occurs. Try to keep the kefir above 20°C

Kefir storage:

Kefir can be stored for at least a week in the fridge. I’ve had kefir that had much more, it just gets more acidic. It probably becomes less rich in micro-organisms and nutrients over time, a bit like yoghurt. I don’t think it can become “bad” in the sense of being dangerous to drink.

Kefir grains Storage

The grains can be kept in water in the fridge for a very long time if you feed them with sugar every 2 weeks (I would say with 5 to 10 times less sugar per gram of grain than to make kefir?) -. Change the water from time to time to limit acidification and eliminate metabolism by-products.

Restarting after storing the grains

It is recommended to do one or more ‘normal’ cycles at room temperature and with 25% more sugar to make vintages from grains that come from the fridge because they are still weakened in the long run.

I’ve heard that the beans can be dried/dehydrated but I’ve never tried it. Also I don’t have any data on freezing but in my opinion it must not be very good.


Lemon can be reused twice, after that it’s not good for much
Figs can eventually be reused as a source of fibre for baking or bread, or in compost. Some people eat it directly.
Excess grains can be eaten, put into baked goods, smoothies, soups, compost, plants, or even the dog.
If you are going to eat the grain, the less you heat it the better.