What are the nutritional data for (strained) water kefir, compared to the starting sugar water?

I would expect there to be less carbohydrates and more vitamins, but haven't the foggiest idea what the actual numbers are.

Bounty: I'm offering a sizable bounty for the best answer. Taste Five's answer gives good theory for what nutrients will change, but I am really after numbers. Answers will be ranked from low to high like so:

  1. Lowest: list of nutrients that increase, no idea as to amount
  2. Lists nutrient changes, rough amounts, and cites a source or sources
  3. Sample nutrition data for one batch, with source listed
  4. Formula for conversion of sugar to other nutrients (I.E. each gram of sugar metabolized turns into X, Y, and Z). Will need a source probably.

I know precise figures will vary from batch to batch with temperature and degree of fermentation; this is understood, and I will accept answers specifying a range of values or just values for one batch or set of kefir grains.

  • Are you looking for just the unflavored water? i.e. just the plain fermented water.
    – jeffwllms
    Jul 15, 2011 at 18:49
  • Yes, just kefir brewed with sugar and water. Or even better, a formula for what the fermentation does to the sugar, in terms of changes in nutrients.
    – BobMcGee
    Jul 15, 2011 at 19:05
  • I would be interested in this as well. As I tried to research it a while ago and found a lot of contradicting information about it. Mainly there was no really study that could conclude the probiotics from kefir did anything to aide in digestion(stating not all probiotics are created equal). All I was able to find at the time was kefir eats the sugar and releases alcohol, lactic acid (might just be when using milk), folic acid, and carbon dioxed.
    – jeffwllms
    Jul 15, 2011 at 19:48
  • BobMcGee if you already have your water kefir grains grains can you share where you got them.
    – jeffwllms
    Jul 15, 2011 at 20:21
  • @Taste Five: I got them off some woman selling on Craigslist. Also, the evidence I found suggested that milk kefir was fairly strongly antimutagenic and the probiotics actually useful for digestion... but there was a lack of similar evidence for water kefir/tibicos.
    – BobMcGee
    Jul 16, 2011 at 4:44

2 Answers 2


Well, the only thing I can offer as an answer at this point would be to use a hydrometer. Measure the specific density before and after. You could then be able to tell how much in sugars you have left.

I can't really think of any good way to tell what bacteria and yeasts will remain in your strained water kefir. I know there has to be some since it will continue to ferment. There really should be some sort of rough guideline that can tell you about how high your probiotic count is based on time or the change in specific density.

I asked a yogurt maker at the store (were I work the cooking school) and he said it would be to hard to work out as it depends on how good your cultures are and so on. Each batch could be so different. He said it likely that your talking a probiotic count in millions-billions per cup and you would have to have each batch tested individually. Which yogurt makers don't really do. Yogurt is not kefir but it is similar so it should be close if not more.

As far as other vitamins and nutrients. You should see some B and C vitamins from the folic and acorbate acids. You can increase the folic acid (B vitamins) by fermenting for longer periods of time but then you will also produce more acetic acid (vinegar). You should be able to get more acorbate acid from more sugar and/or fruit but if you add a lot more you may need to add more kefir grain so it doesn't have to ferment to long(and have a risk of acetic acid again). It seems that this would likely produce more ethanol as well so you would have a slightly higher alcohol content (i have seen some people say they have gotten close to 2% alcohol by volume, but I think most recipes give you in the .2-.5% range).

Any other nutrients seem to have to come from the water (like a mineral water), the sugar (raw sugars tend to have more trace minerals), and the dried fruit.

On a side note, aside from the complex carbohydrate in the sugar, kefir is going to need calcium, magnesium, and potassium to continue to thrive. I remember talking to someone a few years ago that said they let there grains ferment/breed in a mixture of eggshells, raisins and some other things I don't remember now and again to get the grains back into tip top shape. But she also sold the grains so I don't know how needed doing that actually is.

Not sure you will find this to be useful, as I think you might have been looking for something more concrete. And the only DIY test I could find was for vitamin C and it wouldn't even tell you how much, you could just run a comparison before and after and see if it is more. It just seems like there are to many variables involved and not many people seem to do just straight sugar water. Hopefully maybe this will be useful to other people reading the question for at least a starting point on possible adjustments they can make.

  • Hydrometers are rather imprecise. They are usable when determining if home-made brandy is closer to 40° or to 50°; in kefir, the total ethanol content is probably less than the margin of error of the device.
    – rumtscho
    Jul 16, 2011 at 21:27
  • I should be good enough to come up with a fairly decent specific gravity reading(not specific density as I said before). Say you were able to measure that you fermentation lower the specific gravity by 50%. If there was a study done that then turned out a formula for figuring out how much of a certain thing was made based on that you should get a vague idea. I agree though as far as alcohol it would probaly do no good seeing as most kefir would probably be less than .5% by volume. so whatever formula did exsist probably wouldn't tell you much.
    – jeffwllms
    Jul 17, 2011 at 3:53
  • @Taste Five: Hope you won't be offended that I'm offering up a bounty on this one; you've got a serious head start, I'm just seeking more numbers and sources in the answer. A little editing and you might find yourself with double the reputation.
    – BobMcGee
    Jul 28, 2011 at 14:56

There was an NIMH studying exactly this. There are two caveats to this answer. First, it is behind a paywall. Second, every water kefir culture is different and even the same culture will have different balances depending on geographic location, temperature, light, pressure, humidity, and on and on.

This study claims the primary product of fermentation is ethyl alcohol. However, another study (I can't find it right now) claimed alcohol was only produced during the anaerobic stage in the capped bottle and primarily lactic and acetic acid were produced during primary, aerobic fermentation. My guess is the varying results are an artifact of my point two above, namely the variance of kefir based on environmental factors.


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