Composition of Water Kefir Grains: Bacteria and Yeasts


Water kefir grains consist of a complex polysaccharide matrix, upon which live a combination of live bacteria and yeasts existing in a symbiotic matrix.

These include 57 lactic acid bacteria strains, some acetic acid bacteria strains, and at least four yeast strains. Up to 453 different bacterial strains have been identified in water kefir! (Some of these are different subspecies of a single strain, however.) Not all strains are present in all water kefir samples. Differences in the behavior of the grains, the speed at which they multiply, and the type of sugar they perform best with may be due to variations in the bacterial makeup of the particular grains.

We do not test individual batches of water kefir grains for yeast and bacteria content, therefore we cannot make any guarantees to the exact probiotic makeup any particular set of water kefir grains sold on our website. The following is a list of the major species of active bacteria and yeasts that are generally found in water kefir:


Species Lactobacillus
L. brevis
L. casei
L. hilgardii
L. hordei
L. nagelii

Species Leuconostoc
L. citreum
L. mesenteroides

Species Acetobacter
A. fabarum
A. orientalis

Species Streptococcus
S. lactis


Hanseniaospora valbyensis
Lachancea fermentati
Saccharomyces cerevisiae
Zygotorulaspora florentina





Bottled Water Kefir

Related Articles


Related Products

Water Kefir Grains Water Kefir Grains
750 ml Flip top Bottle for Water Kefir 750 ml Flip-top Grolsch-style Bottle

Free eBook Library Access & Weekly Newsletter

Sign up today for free access to our entire library of easy to follow eBooks on creating cultured foods at home, including Lacto-Fermentation, Kombucha, Kefir, Yogurt, Sourdough, and Cheesemaking.
  • Library of eBooks for making your own cultured foods
  • Weekly newsletter filled with tips & tricks
  • Expert advice articles, recipes, and how-to videos
  • Join 150,000+ other health-conscious readers
  • We never share your information!
first name last name email address