How to Make Water Kefir at Home with Kefir Grains
Dissolve 50 g (¼ cup) of sugar in 1 litre of hot water with a dried fig, let it cool to room temperature, then add about 3 tablespoons of water kefir grains. Cover loosely and leave it at 20–25°C (68–77°F) for 24–48 hours, strain out the grains for the next batch, and chill the drink.
Sealed bottles build up gas and can leak or burst, and water kefir contains some alcohol, sometimes more than 1%, so it isn't suitable for children or in pregnancy.
Ingredients
- About 3 tbsp (roughly 50 g), hydrated Water kefir grainsSmall, clear, jelly-like crystals of bacteria and yeast, also sold as tibicos or sugary kefir grains. Milk kefir grains won't work
- 1 litre (4 cups) WaterOrdinary drinking water, part of it boiled to dissolve the sugar
- 50 g (¼ cup) SugarWhite, golden caster or light brown sugar; brown sugar tints the grains tan. This is the grains' food, and most of it is used up
- 1 fig or 1 tbsp raisins Dried fig or a few raisinsOptional but helps: fruit adds nutrients that keep the grains active
- 1 slice Lemon sliceOptional; adds acidity and flavour
Equipment
- Clean glass jar of about 1.5 litres
- Breathable cover (cloth or coffee filter with a rubber band) or a loosely set lid
- Saucepan or kettle
- Fine plastic or stainless-steel sieve
- Swing-top or screw-top bottles rated for fizzy drinks, for the second ferment
Method
Clean everything
Wash your hands, jar, sieve and spoon in hot soapy water and rinse well. Public health guidance on water kefir stresses clean equipment, and sieves in particular, because pathogens brought in on equipment or ingredients can survive.1
Make the sugar water
Bring about 250 ml (1 cup) of the water to the boil, take it off the heat, and stir in the sugar until it dissolves. Add the fig or raisins to the hot water too: BC Centre for Disease Control advises heating the sugar and fruit mixture, not just the water, to kill any germs.1
Cool it to room temperature
Pour the sweet water into the jar and add the remaining 750 ml (3 cups) of cold water. Check it has cooled to room temperature before adding the grains, as heat can harm them. BCCDC advises cooling within 2 hours.1
Add the grains and cover
Add the grains, and the lemon slice if using. Cover the jar with a cloth and rubber band or a loosely set lid so gas can escape; don't seal it tight at this stage.1
Ferment for 24–48 hours
Leave it out of direct sun at room temperature, ideally 20–25°C (68–77°F). Reviews give 24–72 hours at that temperature; 24–48 hours suits most kitchens. It is ready when it tastes noticeably less sweet, slightly tart, and small bubbles rise. Longer gives a drier, more sour drink.1,3
Strain and reuse the grains
Strain the kefir through a clean sieve into a jug and pick out the fruit and lemon. Put the grains straight into a fresh batch of cooled sugar water. More grains use the sugar faster, which raises the alcohol, so remove some as they multiply.1
Chill, or bottle for a second ferment
Water kefir contains live cultures and should be refrigerated at 4°C (40°F). Drink it as it is, or bottle it with a little fruit juice for extra fizz (below).1
Optional: a second ferment for fizz
Add about 2 tablespoons of fruit juice, or a few pieces of fruit or ginger, to each 500 ml bottle and close it. The process reviewed by BCCDC does this in the fridge for at least 24 hours. Many home brewers leave bottles at room temperature for 12–24 hours instead, which is fizzier but builds pressure and alcohol faster, so open them daily over the sink.1
Safety
- Sealed bottles build up carbon dioxide and can leak, burst or shoot their caps. Use bottles made for fizzy drinks, chill them and don't shake them1
- Water kefir contains alcohol, usually under 1% but over 2% in some tests. Not for children, in pregnancy or for anyone avoiding alcohol1,3
- Weakened immune system? Ask a doctor first: live microbes carry more risk with serious illness, and UF Extension says you may want to avoid homemade kefir5,6
- Throw out the batch and grains if you see fuzzy mould, or it smells rotten or like nail-polish remover rather than fresh and tart
- Heat the sugar water and fruit before adding grains, and use clean equipment: pathogens on fruit or equipment can survive the ferment1
Variations
Add a few thin slices of fresh ginger and a squeeze of lemon to the bottles for the second ferment. Ginger ferments vigorously, so release the pressure more often.
Add a few crushed raspberries or blackberries, or 2 tablespoons of berry juice, to each 500 ml bottle for colour and flavour.
Ferment the grains in coconut water instead of sugar water for a softer, less sweet drink. Do this for a batch or two at most, then return them to sugar water.
To take a break, put the grains in fresh sugar water with a lid in the fridge for up to a week or two, then do a batch or two at room temperature to wake them before drinking the result.
Does it actually work?
Water kefir is a lightly fizzy, low-sugar fermented drink, and its microbes are well described: lactic-acid bacteria, acetic-acid bacteria and yeasts living in the grains. Which species dominate depends on where the grains came from and how they are fed, so every kitchen's water kefir is a little different.
What it does for health in people is largely untested. A 2024 review lists possible anti-inflammatory, blood-pressure and cholesterol effects but notes there is a big gap in human studies; most of the evidence comes from animals and laboratory work.
The main human study so far gave 40 healthy adults 200 ml of homemade water kefir a day for 14 days. Their gut bacteria shifted, about a third reported more wind and a quarter bloating, and two-thirds noticed no change. There was no control group, and the authors say it can't show cause or any clinical benefit. For what specific probiotic strains can and can't do in trials, see our probiotics entry.2,3,4,5
Evidence ratings for what goes in: Probiotics (Lactobacillus).
Questions people ask
Does water kefir contain alcohol?
Yes. Yeasts in the grains turn some sugar into alcohol. Reviews say it is usually under 1%, but tests have found over 2%, and fruit-juice versions up to about 5%. Longer ferments, more grains and sealed second ferments raise it.
What is the difference between water kefir and milk kefir?
They use different grains that can't be swapped. Water kefir grains are small, clear crystals fed on sugar water or juice, making a light, dairy-free fizzy drink; milk kefir grains are white, cauliflower-like clumps that ferment milk.
Why is my water kefir not fizzy?
The first ferment is only lightly bubbly because gas escapes. For fizz, do a second ferment in closed bottles with a little fruit juice. Grains that are new, cold or underfed can also be slow: feed them fresh sugar water for a few batches.
How much sugar is left in water kefir?
Less than went in, because the grains eat it, but how much is left varies with time, temperature and how many grains you use. A longer ferment leaves a drier, less sweet drink, though with more alcohol and acid.
Is water kefir a probiotic?
It contains live bacteria and yeasts, but NCCIH notes that different probiotics have different effects, and the evidence is for defined strains. Water kefir's microbes vary from batch to batch and haven't been tested that way; the few human studies are small and uncontrolled.
Sources (6)
- Public health guidance Parto N, Loewe C. Section 3.12 Kefir. In: McIntyre L (ed.). Safety of fermented foods. Environmental Health Services, BC Centre for Disease Control. December 2024.
- Review Lynch KM, Wilkinson S, Daenen L, Arendt EK. An update on water kefir: Microbiology, composition and production. Int J Food Microbiol. 2021.
- Review Bozkir E, Yilmaz B, Sharma H, et al. Challenges in water kefir production and limitations in human consumption: A comprehensive review of current knowledge. Heliyon. 2024.
- Uncontrolled trial de Mel R, Al Khafaji AH, Muthusamy S, Xu J, Håkansson Å. Changes in gut microbiota composition following water kefir consumption in healthy adults. Sci Rep. 2026.
- Regulator/health agency NCCIH. Probiotics: Usefulness and Safety. National Center for Complementary and Integrative Health.
- University extension Skinner JR. Fermented Foods: Kefir. UF/IFAS Extension FSHN24-2/FS457. 2024.
Educational only. Patch-test anything new on your skin, and stop if it irritates.
Reader notes
Experiences and questions from readers, read by an editor before they appear. They are personal accounts, not evidence, and are not medical advice.