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Water kefir: grains and their care

Water, sugar, dried fruit and grains you can use again. How to make the drink, how to keep the grains alive and when to throw them out.

8 min read First steps Reviewed October 26, 2026 50 facts, each with its source

What the grains are

Water kefir grains, also called tibicos, are lactic acid bacteria, acetic acid bacteria and yeasts1. They look like small, irregular, translucent crystals2. They ferment water with sugar and fruit, and in two to four days they make a yellowish drink that is fizzy, sour, slightly sweet and slightly alcoholic3. Then they're strained out and used again. Milk kefir grains don't work for water, or the other way around4.

Getting and activating the grains

You can get grains live, frozen or dehydrated. Frozen and dehydrated grains have to be reactivated before you use them5. Put them in water with 10–15% sugar6, boiled and cooled from 60 °C to 21–24 °C (140 °F to 70–75 °F) in under 2 hours7, and leave them for 3 to 4 days at 20–30 °C (68–86 °F), until they look plump and translucent8.

If someone gives you live grains, have them come in a little of their sugar water: use them that day or keep them in the fridge. Don't start a batch with grains that aren't active. BCCDC, British Columbia's public health agency, treats this as a critical control point9.

The base: water, sugar and fruit

Fervida's recipe uses 1 liter (1 quart) of water, 60 g (5 tablespoons) of sugar, two dried figs and a slice of lemon. Dried figs are the most common fruit10, and their calcium, like that of hard water, helps the grains grow11. Lemon lowers the pH12.

  • Sugar. Studies use 5 to 10%13, and BCCDC sets the maximum at 10%, 100 g per liter14. With a lot of sugar, pathogenic bacteria compete better against the grains15; with no sugar or fruit, it ferments slowly and the pH stays high16. The 60 g per liter is a house rule. Brown sugar tints the grains tan, and that's not a defect17.
  • Water. The grains need minerals. Reverse osmosis, carbon-filtered and distilled water aren't recommended, and neither is tap water with chlorine or fluoride18. Use still mineral water.
  • Boil and cool. The water, sugar and fruit are boiled together, or pasteurized at 85 °C (185 °F) for 16 seconds19. Then they have to drop from 60 °C to 21–25 °C (140 °F to 70–77 °F) within 2 hours, and never take more than 620.

Fermenting: 1 to 4 days, with the pH measured

Add about 50 g of grains per liter, 5%21. Don't add more: with more grains the sugar is used up faster and there's more alcohol22. Use a glass jar with the lid on loosely or an airlock lid: water kefir ferments closed, but the gas has to get out23. Use a plastic spoon and strainer, because the grains react with iron, copper, aluminum and other metals24.

Temperature Time
Below 20 °C (68 °F) Slower; there are no figures
20–25 °C (68–77 °F) 48 to 96 hours according to BCCDC25; 24 to 72 according to studies13
25–30 °C (77–86 °F) 20 to 24 hours, on what little research there is26
Above 30 °C (86 °F) Don't ferment it: a house rule, because there's no data

Measure the pH before 96 hours. It has to drop to 4.6 or lower within 2 to 4 days27, and never below 2.528. After 3 days at 21 °C (70 °F), a pH of 3.3 to 3.6 is normal29. If it hasn't reached 4.6 at 96 hours, throw it out.

With the jar open, acetic acid bacteria take over: you get more acid, a vinegar taste and less alcohol30.

Straining and storing the drink

Sanitize the strainer before each use31: a minute in boiling water does it32. Strain, keep the grains and pour the drink into a bottle. It has to reach 4 °C (40 °F) within 4 hours, and never take more than 633, because it's a live drink and always goes in the fridge34. No source says how long it keeps35: Fervida gives 7 days, and that's a house rule. In the bottle it keeps making gas, and the liquid can rush out when you open it36.

For flavor and fizz, it's bottled with fruit and without the grains. BCCDC does that second fermentation in the fridge, for at least 24 hours37. Fervida's strawberry and ginger recipes leave it out for up to 48 hours, in bottles made for carbonation and with a test bottle. Those are house rules, explained in "Carbonation and exploding bottles".

Caring for the grains

Grains do well when they keep working: you can use them right away in a new base38. Well cared for, they grow: BCCDC uses a 75% gain in weight in 24 hours as a benchmark39. Poor growth is water kefir's main problem40; if it happens to you, check the water, the fruit and the sugar. Weigh them now and then and keep 50 g per liter. You can give away the extra.

If you're taking a break, keep them in the fridge, at 4 °C (40 °F), in boiled and cooled water with 5% sugar (50 g per liter). In one study they lasted 30 days this way41, and the authors recommend the fridge for storing them42. Don't freeze them: freezing and thawing damages them for good43. Cold and acid make them slower to get going44, so the first batch after a break may be slow.

What can go wrong

What you see What to do
Grains that grow slowly, change color or smell, or stop fermenting Throw them out45
Green, blue, brown or black mold Throw it all out, grains included46
A putrid smell It's a failed ferment: throw it out47
pH above 4.6 at 96 hours Throw it out and check the grains
Tan grains, if you use brown sugar Nothing: it's the color of the sugar

It contains alcohol

Thirteen samples of water kefir tested in Argentina had between 0.58 and 2.55% alcohol48. Made with fruit or vegetable juices, it can go above 1%49. That's why it's not for young children or during pregnancy50. What makes it rise is in "Alcohol in kombucha and kefir".

The recipes

  • Water kefir: the base recipe, with dried figs and lemon.
  • Strawberry water kefir and ginger lemon water kefir: second fermentations in the bottle, with fruit and fizz. Both start from the base kefir, already strained and measured.

Where every number comes from

Every number in the text leads to its figure: the exact sentence from the official guide it comes from, in its own language.

  1. 1

    Lactic acid bacteria, acetic acid bacteria and yeasts

    “Generally, the microorganisms used for the production of water kefir grains belong to lactic acid bacteria (LAB), acetic acid bacteria (AAB), and yeasts”

    Heliyon (Elsevier), open access via PubMed Central · Challenges in water kefir production and limitations in human consumption: A comprehensive review of current knowledge (2024) · read on October 25, 2026

  2. 2

    Small, irregular, translucent grains that look like crystals

    “Water kefir grains are smaller than milk kefir grains and look like tiny, irregular-shaped translucent, crystal granules.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  3. 3

    In 2 to 4 days, a fizzy, sour, slightly sweet and slightly alcoholic drink

    “After 2 to 4 days of anaerobic incubation at room temperature, a sparkling, yellowish fermented beverage is obtained that has a fruity, acidic, slightly sweet, and slightly alcoholic taste and aroma.”

    Applied and Environmental Microbiology (Laureys & De Vuyst), via PubMed Central · Microbial species diversity, community dynamics, and metabolite kinetics of water kefir fermentation (2014) · read on October 25, 2026

  4. 4

    Milk grains don't work for water kefir, or the other way around

    “milk grains cannot be used to make water kefir or vice versa.”

    Colorado State University Extension (FoodSmart Colorado) · Understanding and Making Kefir · read on October 20, 2026

  5. 5

    Frozen or dehydrated grains have to be reactivated

    “New kefir grains (frozen or dehydrated) will need to be reactivated before use.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  6. 6

    They're activated in water with 10–15% sugar

    “inactivated water kefir grains can be activated by placing the grains in 10-15% sugar solution.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  7. 7

    That sugar water boiled, then cooled from 140 °F to 70–75 °F within 2 hours

    “Pasteurize the sugar solution first, for example, boil water and sugar and cool to inoculation temperature, from 60oC to 21-24°C within 2 hours before addition of the water kefir grains.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  8. 8

    3 to 4 days at 68–86 °F, until they look plump and translucent

    “hold at 20-30°C for 3-4 days, until the grains look plump and translucent.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  9. 9

    Using active grains is a critical control point

    “Using activated milk or water kefir grains is a critical control point (CCP).”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  10. 10

    Dried figs are the most common fruit

    “Dried figs are the most common fruit added”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  11. 11

    Calcium from figs and hard water helps the grains grow

    “Of interest, figs are high in calcium, and reports that both figs and hard water (containing more calcium and magnesium ions) promotes water kefir grain growth in comparison to other fruits lower in calcium and soft water.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  12. 12

    Lemon lowers the pH

    “Reduce pH by adding citric acid (lemon slices) or equivalent to lower pH.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  13. 13

    5 to 10% grains and sugar, at 68–77 °F for 24 to 72 hours

    “Traditionally, water kefir is prepared by the addition of 5–10 % (w/v) of water kefir grains in 5–10 % (w/v) sucrose solution, followed by fermentation at room temperature of 20–25 °C in anaerobic conditions for 24–72 h”

    Heliyon (Elsevier), open access via PubMed Central · Challenges in water kefir production and limitations in human consumption: A comprehensive review of current knowledge (2024) · read on October 25, 2026

  14. 14

    At most 10% sugar

    “Add up to 10% w/v sucrose (sugar) along with dried fruits (e.g., figs) or juice extracts.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  15. 15

    With a lot of sugar, pathogenic bacteria compete better

    “High sugar concentration in the starting mixture can also encourage pathogenic bacteria to compete with kefir grains microorganisms.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  16. 16

    Without fruit or sugar, it ferments slowly and the pH stays high

    “Low nutrient concentration (i.e., absence of fruits or added sugars) in the starting mixture can slow fermentation, resulting in lower metabolic activity of kefir grain culture, higher kefir pH and create potential for pathogenic growth.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  17. 17

    Brown sugar tints the grains

    “use of brown sugar adds tan colour to water kefir grains”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  18. 18

    No reverse osmosis, carbon-filtered, distilled or chlorinated tap water

    “As trace minerals are required by the kefir grains, use of reverse osmosis, carbon filtered, and distilled water was not recommended, as was use of tap water containing chlorine or fluorides”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  19. 19

    The base boiled, or pasteurized at 185 °F for 16 seconds

    “Heat to boiling and/or pasteurize water, juice, added sugars and fruits to achieve a 5-log reduction (e.g., to 85oC for 16 sec or equivalent).”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  20. 20

    From 140 °F to grain temperature within 2 hours, never more than 6

    “Kefir is cooled from 60oC to inoculation temperature within 2 hrs (no longer than 6 hrs).”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  21. 21

    Active grains, about 5%

    “Kefir grains must be activated (active), and sufficient grains added (approx. 5% w/v).”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  22. 22

    More grains, more alcohol

    “Higher volumes of water kefir grains can consume sucrose rapidly in the first 24 hours of fermentation, leading to higher alcohol contents.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  23. 23

    A closed container that lets gas out

    “Typically water kefir fermentations are conducted in sealed containers that are vented to allow gases to escape.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  24. 24

    The grains react with metals

    “equipment made from iron, copper, aluminium, or other metals is not suggested to be used since grains are reactive to these metals”

    Heliyon (Elsevier), open access via PubMed Central · Challenges in water kefir production and limitations in human consumption: A comprehensive review of current knowledge (2024) · read on October 25, 2026

  25. 25

    48 to 96 hours at 70–77 °F

    “The mixture is fermented at 21-25oC for 48-96 hrs, under anaerobic conditions.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  26. 26

    At 77–86 °F, 20 to 24 hours, on limited research

    “Fermentation time may be shortened by a higher incubation temperature (e.g. 20-24 hrs at 25-30oC) based on limited research.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  27. 27

    pH 4.6 or lower within 2 to 4 days

    “a pH of 4.6 or lower should be verified, regardless within 2 to 4 days (48-96 hrs).”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  28. 28

    pH 4.6 or lower, never below 2.5

    “Ensure the pH of final product is 4.6 or less, but not lower than pH of 2.5.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  29. 29

    pH 3.3 to 3.6 after 3 days at 70 °F

    “A few studies have reported a final pH of 3.3-3.6 for water kefir fermented at 21oC for 72 hours”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  30. 30

    With air, more acetic acid and less alcohol

    “In the presence of oxygen, AAB proliferate resulting in the production of high acetic acid that may not be aesthetically desirable, although alcohol content will be lower.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  31. 31

    The strainer sanitized before each use

    “Sanitize sieves before each use.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  32. 32

    One minute in boiling water

    “For example, immerse sieves in boiling water for a minute to sterilize before use.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  33. 33

    Down to 40 °F within 4 hours

    “Cool to 4oC immediately, within 4 hrs (no longer than 6 hrs)”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  34. 34

    It's a live drink and goes in the fridge

    “Water kefir contains live culture and requires refrigeration.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  35. 35

    There's no data on how long it keeps in the fridge

    “No information on the shelf life of kefir made with water kefir grains can be found.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  36. 36

    Gas builds up and pushes the liquid out

    “Excess pressure can build-up from carbon dioxide, causing fluids to leak out.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  37. 37

    BCCDC does the second fermentation with fruit in the fridge, for at least 24 hours

    “Secondary fermentation steps that add additional fruit or fruit juices, for example, apple, pineapple, lime, lemon, mango, cherries, or strawberries occur after grain removal and should be performed in the refrigerator for at least 24 hrs.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  38. 38

    Grains are reused right away or stored

    “Grains can be reused immediately in a new fermentation or at a later time if preserved in appropriate conditions.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  39. 39

    Well cared for, they gain 75% in weight in 24 hours

    “For example, when optimized water kefir grain mass growth should increase by 75% over a 24 hour period.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  40. 40

    Poor growth is water kefir's main problem

    “Unstable fermentation and low grain growth are the main limitations of the industrial production of water kefir.”

    Heliyon (Elsevier), open access via PubMed Central · Challenges in water kefir production and limitations in human consumption: A comprehensive review of current knowledge (2024) · read on October 25, 2026

  41. 41

    30 days in the fridge, in water with 5% sugar

    “One group was stored in sterile 5% (w/v) sugared water at +4°C for 30 days”

    Food Science & Nutrition (Gökırmaklı, Şatır & Guzel-Seydim), via PubMed Central · Microbial viability and nutritional content of water kefir grains under different storage conditions (2024) · read on October 25, 2026

  42. 42

    To store them, fridge and sugar water

    “When storage is necessary, it is recommended to store the WKG at +4°C in sugared water.”

    Food Science & Nutrition (Gökırmaklı, Şatır & Guzel-Seydim), via PubMed Central · Microbial viability and nutritional content of water kefir grains under different storage conditions (2024) · read on October 25, 2026

  43. 43

    Freezing damages them for good

    “Laureys et al. (2017) reported that freezing and thawing WKG resulted in irreversible damage.”

    Food Science & Nutrition (Gökırmaklı, Şatır & Guzel-Seydim), via PubMed Central · Microbial viability and nutritional content of water kefir grains under different storage conditions (2024) · read on October 25, 2026

  44. 44

    After the cold they take longer to get going

    “Acidified water and low temperatures will stress water kefir grain activity, requiring longer periods to reactivate.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  45. 45

    If they grow slowly or change color or smell, they go

    “If kefir grains grow slowly, if the grains develop unusual colour, odour, or if grains lose activity, grain function is compromised, and they should be discarded.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  46. 46

    Green, blue, brown or black mold: throw it out

    “If you confirm mold growth on any part of a ferment, it should be immediately discarded. Mold is typically green, blue, brown, or black in color.”

    UC Davis, Department of Food Science and Technology · Common issues with fermented fruits and vegetables (v1.0, 15-mar-2022) · read on October 20, 2026

  47. 47

    A putrid smell means a failed ferment

    “A putrid smell indicates a failed fermentation.”

    UC Davis, Department of Food Science and Technology · Common issues with fermented fruits and vegetables (v1.0, 15-mar-2022) · read on October 20, 2026

  48. 48

    Between 0.58 and 2.55% alcohol in 13 samples

    “un contenido de alcohol entre 0,58 y 2,55 (%, v/v)”

    Revista Argentina de Microbiología (Teijeiro et al.; INAL-ANMAT, CONICET) · Análisis de muestras de kéfir de agua para el desarrollo de un marco regulatorio en el Código Alimentario Argentino (2025) · read on October 25, 2026

  49. 49

    Made with juices, it can go above 1% alcohol

    “Of concern, water kefir made from vegetable or fruit juices may contain high levels of alcohol (≥1%).”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

  50. 50

    Not for young children or during pregnancy

    “May contain alcohol. Not a suitable beverage for young children or during pregnancy.”

    BC Centre for Disease Control, Environmental Health Services · Safety of Fermented Foods, Section 3.12: Kefir, milk and water (December 2024) · read on October 25, 2026

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