How to make it
How to make water kefir, the dairy-free fizzy ferment
A lightly fizzy, sour-sweet drink made by fermenting sugar water and a dried fig with water kefir grains. No extension service has tested a home recipe yet, so this one uses the conditions reported in research.
By the editors of Alimentotherapy Last reviewed 5 min read Not medical advice
- Makes
- About 1 liter (4 cups)
- Hands-on
- 10 minutes
- Total time
- 1 to 3 days
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The short answer
Ferment about 100 g of sugar and a dried fig in 1 liter of water with roughly 60 g of water kefir grains at 68 to 77°F (20 to 25°C) for 24 to 72 hours, the range a 2024 review reports for water kefir productionBozkir 2024. The only human study we found was small and had no control group: 40 healthy adults drank 200 ml a day for 14 days and their gut bacteria shifted, but the authors note causality cannot be establishedDe 2026. Our fermented foods page grades the human evidence for fermented foods as limited.
Ingredients and method
Ingredients
- 1 liter (about 4 1/4 cups) water
- 100 g (about 1/2 cup) white or unrefined cane sugar (studies use 60 to 100 g per liter)
- About 60 g live water kefir grains
- 1 dried fig, preferably unsulfured
- Optional: 1 slice of lemon
Equipment
- 1 1/2 to 2 quart glass jar (not glazed ceramic or metal)
- Cloth or coffee filter and a rubber band
- Plastic or fine stainless steel strainer
- Kitchen scale
- Thermometer for the room, and pH test strips
- Clean glass bottles with caps, if you want a fizzier second ferment
Clean
Wash your hands, the jar, strainer and bottles in hot soapy water and rinse well.
Dissolve the sugar
Dissolve the sugar in a little warm water in the jar, then add the rest of the water cold. Let it come to room temperature before the grains go in.
Add grains and fruit
Add the water kefir grains, the dried fig and the lemon slice if using. Cover the jar with a cloth or coffee filter held on with a rubber band.
Ferment 24 to 72 hours
Leave it out of direct sun at 68 to 77°F (20 to 25°C). Most of the sugar is used up in the first day; the drink keeps getting more sour up to about 3 days. Taste from 24 hours.
Check and strain
It should smell clean, sour and yeasty and be slightly cloudy and bubbly; a pH strip should read below 4.6, and finished water kefir is usually around 3.5 to 4.5. Strain out the grains and fig. Return the grains to fresh sugar water for the next batch.
Second ferment for fizz (optional)
Pour the strained kefir into bottles with a splash of fruit juice, cap them and leave at room temperature for about a day. Pressure builds fast: open one carefully to check, then refrigerate all of them.
Keep it cold
Refrigerate the finished drink and drink it soon; there is no tested storage time for homemade water kefir.
If you need the equipment
What water kefir is
Water kefir is a sparkling, slightly acidic drink made by fermenting a sucrose solution, usually with dried fruit added, using water kefir grains: gelatinous clusters of lactic acid bacteria, yeasts and acetic acid bacteria held in a sugar-based matrix Lynch 2021. The grains are a different culture from milk kefir grains, and the two cannot be swapped. If you want the dairy version, see milk kefir.
Unlike sauerkraut, kombucha or milk kefir, water kefir has no tested extension-service recipe in the US that we could find. The amounts on this page come from research instead. A 2024 review reports fermentation at 20 to 25°C for 24 to 72 hours, usually with 6 to 10 percent sucrose and 6 to 20 percent grains, and lists one study recipe of 60 g of grains per liter of water with 10 percent sucrose and one dried fig, fermented for 24 hours at room temperatureBozkir 2024. We used that as the base.
What happens in the jar
A Belgian study that followed one water kefir fermentation for 192 hours found the sucrose was completely used up after 24 hours. The main products were ethanol and lactic acid, most of them formed in the first 72 hours, while the pH fell from 4.26 to 3.45 Laureys 2014. That is why a one-day ferment tastes sweeter and a three-day ferment tastes sharper and drier.
Safety
Alcohol is part of the process. The 2024 review describes finished water kefir as generally below 1 percent alcohol with a pH of about 3.5 to 4.5 Bozkir 2024. Home batches are not measured, so assume it is a drink with some alcohol. Like kombucha, it is acidic enough that UGA Extension’s advice for kombucha applies: do not ferment or store it in glazed earthenware, which can leach heavy metals Uga.
Does water kefir do anything?
Reviews list a long run of possible properties for water kefir, from antimicrobial to anti-inflammatory activityBozkir 2024, but possible properties are not tested health effects in people. The one human study we found gave 40 healthy adults 200 ml of homemade water kefir a day for 14 days. Their gut bacteria shifted, with more Bifidobacterium among other changes, but overall diversity within each person did not change, there was no control group, and the authors state that causality cannot be established. About a third reported flatulence (32 percent) and a quarter bloating (24 percent), mostly mild and passing De 2026.
So drink it as a less sweet alternative to soda if you like the taste. For the evidence on fermented foods in general, see fermented foods and the gut microbiome page, and for a side-by-side with the tea ferment, kombucha vs kefir.
Getting grains
Water kefir grains multiply in sugar water, so a friend who makes it can often spare some.
Food safety
- Discard any batch with fuzzy mold, a rotten or putrid smell, or sliminess in the liquid, and clean the jar well.
- Sealed bottles can build enough carbon dioxide to burst. Refrigerate after a short second ferment and open bottles slowly, pointed away from your face.
- Water kefir contains a little alcohol, usually under 1% in studies; home batches are not measured. Skip it if you are pregnant, avoiding alcohol, or giving it to children.
- Ferment and store in glass. Acidic drinks can leach lead from glazed ceramics.
- Expect some gas or bloating when you start; begin with a small glass.
- If you have a weakened immune system or are seriously ill, ask your care team before drinking home ferments.
Common questions
How much sugar do you use for water kefir?
Studies typically use 6 to 10 percent sucrose, which is 60 to 100 g of sugar per liter of water, according to a 2024 review in Heliyon. Fermentation uses up most of it: in one study the sucrose was gone after 24 hours.
How long does water kefir take to ferment?
24 to 72 hours at 20 to 25 degrees C (68 to 77 degrees F), per a 2024 review. A one-day ferment is sweeter; by three days it is more sour, with the pH falling to about 3.5 in one study.
Does water kefir contain alcohol?
Yes, a little. Ethanol and lactic acid are its main fermentation products, and a 2024 review puts finished water kefir generally below 1 percent alcohol. Homemade batches vary and are not measured.
Sources
Primary research and government sources, each checked on the date this page was reviewed.
- SourceBozkir E, et al. Challenges in water kefir production and limitations in human consumption: a comprehensive review of current knowledge. Heliyon. 2024. (Production conditions from the full text.)
- PubMedLaureys D, De Vuyst L. Microbial species diversity, community dynamics, and metabolite kinetics of water kefir fermentation. Appl Environ Microbiol. 2014. PMID 24532061.
- PubMedLynch KM, et al. An update on water kefir: microbiology, composition and production. Int J Food Microbiol. 2021. PMID 33751986.
- PubMedde Mel R, et al. Changes in gut microbiota composition following water kefir consumption in healthy adults. Sci Rep. 2026. PMID 42174008.
- GuidelineCullinan S, et al. What's the Word on Homemade Kombucha? University of Georgia Extension Circular 1312. 2024, revised 2026.
Keep reading
- RemedyFermented foodsSauerkraut, kimchi, miso, kefir and kombucha. One well-run trial suggests eating more of them changes the gut microbiome; claims beyond that are mostly untested in people.
- Kitchen practiceFermentationThe oldest way to keep vegetables through winter. A tested method, the right salt and clean equipment make it safe; the health claims are more modest than the hype.
- How to make itMilk kefirKefir grains in a jar of pasteurized milk, left on the counter for a day. It is the easiest ferment to keep going, and kefir has one of the better-supported uses in the kitchen: easier lactose digestion.
- ComparisonKombucha vs kefirBoth are fizzy fermented drinks, but they start from different things: kombucha from sweet tea, kefir from milk (or sugar water for water kefir). Kefir has a little human evidence; kombucha has nearly none.
- GoalFood and the gut microbiome: fiber, fermented foods and probioticsMicrobiome science is young. A varied, fiber-rich diet is sensible on many grounds, one small trial found fermented foods raised microbe diversity, and probiotic evidence is strain- and condition-specific.