Fermentation V: Water Kefir

I am experimenting  with kombucha and its culinary uses, but for daily drinking I prefer water kefir. It’s a fermented drink with a mildly yeasty tangy flavor and none of the vinegary overtones of kombucha. It can be flavored in a lot of ways, and it’s quick and fun to make.

It’s produced by a SCOBY, a symbiotic colony of bacteria and yeast, but rather than form a solid mat the kefir SCOBY forms rounded globules called “grains.” I had trouble getting started because I kept buying dehydrated grains that never came to life. Finally I bought fresh grains from Florida Sun Kefir and they got off to a flying start. The substrate is water with 1/4 cup of sugar per quart of water dissolved in it. I use a mixture of white and coconut sugar, and brew about two quarts at a time. Pour the water mixture over the grains, screw the lid on loosely or cover with a dish towel tied on tightly, and let it sit at room temperature for 36-48 hours. The grains are in motion during fermentation, rising through the fluid, discharging their cargo of carbon dioxide into the air, and sinking slowly back to the bottom of the jar. They will slow down as the sugar is exhausted. I tell when it’s ready by tasting. When the sugar is fermented totally and none is detectable to taste, it’s done.  I pour off most of the fluid in the jar through a mesh strainer and refrigerate until I want to drink it. If you want yours a bit sweet, stop sooner, but I prefer to sweeten artificially before drinking. Leave the grains in enough finished kefir to cover them, add more sugar water, and the grains are off and running again.  I then add flavoring and some artificial sweetener, carbonate in my nifty Drinkmate, and enjoy. My favorite flavorings are vanilla or a little good root beer extract or a bit of grated ginger juice. There are all sorts of possibilities including adding fruit juice.`

I find the Drinkmate to be the easiest and most exact method of carbonation. I have found the “natural” method to produce erratic and undependable results, but if you want to try it, try out these directions: http://www.resetyourweightbasics.com/healthy-kefir-soda/.

I can’t explain this, but water kefir really does seem to decrease appetite. I don’t vouch for this effect because I do not find any scientific literature on it except the one animal-model reference below,  but try it for yourself and see what you think.

Your grains will multiply steadily and always need food. If you want to store them for awhile, put the jar in the refrigerator immediately after adding fresh sugar water and they will keep about two weeks. For longer storage, drain them every two weeks and add fresh sugar water. You’ll soon have plenty of grains to give to friends.  Internet sources tell you to add dried fruit and eggshells for minerals, but I have never done that and my grains multiply  just fine. It might be that the coconut sugar I use provides the grains with any minerals that they need. My grains are tan rather than white after several generations in coconut sugar.

In the picture below, what looks like a film on the surface is actually a haze of tiny bubbles of carbon dioxide bursting.

One caveat: I can’t find reliable data on this but judging from its effect on me I think that my homebrew kefir has substantially more alcohol that most SCOBY-brewed products, maybe as much as 2-3%. This might not sound like much, but you don’t want to work or drive on the amount of alcohol in a standard 12oz glass. I keep this for evening enjoyment. But I may be incorrect about this,or brewing conditions may affect the ethanol content. Here’s a marvelously nerdy article analyzing the components of water kefir: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3993195/pdf/zam2564.pdf

I can’t stop talking about the marvelous Noma Guide to Fermentation. It doesn’t address water kefir specifically, but I’m curious about the possibilities of cooked-down kefir essence used in the way that the Noma people use kombucha essence. It might also be possible to grow out water kefir grains in other fluids such as juices. After making a few batches of standard water kefir, you will have plenty of grains with which to experiment.

Many internet sources that discuss water kefir give references for its health benefits. However, I spent a cold gray afternoon indoors looking up those references and found that, as I had suspected, nearly all of them actually refer to milk kefir. I don’t find a lot of data on whether water kefir contains the same microorganisms as the milk product, and certainly its nutrient content is different. Here are a few references on water kefir specifically.

Inhibition of metastasis of breast cancer cells in vitro and in vivo in a mouse model:

https://www.ncbi.nlm.nih.gov/pubmed/27230756

Isolation of a novel bifidabacterium strain with probiotic potential from water kefir:

https://www.ncbi.nlm.nih.gov/pubmed/26739269

Analysis of organisms from water kefir, showing that its biotic complexity is higher than previously realized: https://www.ncbi.nlm.nih.gov/pubmed/23289707

Evaluation of Lactobacilli strains found in water kefir for probiotic potential:
https://www.ncbi.nlm.nih.gov/pubmed/30319846

Anti-obesity effects in an animal model of water-soluble polysaccharides found in the matrix of kefir grains:

https://www.ncbi.nlm.nih.gov/pubmed/29084388

This last one is particularly interesting because the mice given kefir matrix exopolysaccharides showed anti-obesity effects on an excessive diet and also showed higher levels of Akkermansia bacteria in their feces. Other data (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3670398/ ) indicates that the presence of Akkermansia species in both rats and humans inversely correlates with obesity, probably via interactions with the gut epithelium. Please don’t try to make too much of this: the science of the biome is in its infancy and we know very little about how to impact it for specific effects. So I can only say that water kefir won’t hurt you and may have some beneficial effect.

 

 

2 responses to this post.

  1. Oral memories suggest that a water keffir organism may have been used as a soft drink for children here just after the war. Called ‘the water beast’ (in the gaelic). Unfortunately it seems to have died out like many other traditions….

    Reply

    • Posted by wooddogs3 on December 7, 2018 at 4:40 pm

      That’s fascinating! And the purposeful grains in constant motion do seem more like pets than microorganisms.

      Reply

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