Kefir

The Other Fermented Drink

They promptly arrived in the mail, as all “live material” should, and agreeably slid from double Ziploc bags into the new homes I’d prepared for them: a jar of milk and a jar of sugar water. Thus begins my fun experiment, I thought. Later I’ll think of that day as the beginning of my indenture to kefir grains.

Rubbery and translucent and cauliflower-shaped, my kefir grains — more like globs — range in size from a sunflower seed to a peanut. They are composed of multiple species of yeasts and bacteria that live in and on a material of their own creation: a matrix of sugars bound together into chains called polysaccharides. Think of stiff Jell-o or a beached jellyfish for textural comparison, although the vegetarian alternatives of agar and pectin are more chemically similar. As such, kefir grains belong to the family of beverage-fermenters involving SCOBY — shorthand for Symbiotic Community Of Bacteria and Yeast.

I’ve purchased two different but similar SCOBY. Milk kefir grains are white and thrive on the sugars and protein of any type of milk, fermenting it into kefir — a sort of runny yogurt full of so-called probiotics that can be used as a milk or buttermilk substitute. Its roots can be traced back to the Old World, where, not coincidentally, cows, goats, and sheep are also from, and is mainly consumed in the Middle East, the Caucasus region, and Russia. The smaller colorless grains I’ve purchased are commonly called water kefir but are also known as tibicos or simply tibi. These are typically used to ferment juices or syrups. It is thought that tibicos originated from naturally occurring SCOBY, as dried grains of similar composition have been found on prickly pear cactuses in Mexico. Tibicos is therefore the New World analog to kefir, and both beverages have been gaining in popularity in the United States for the many alleged health benefits of probiotics.

As I placed the two loosely-covered mason jars, one of milk and the other sugar water, both with their respective SCOBY added, on the counter next to my sourdough starter, I pondered: Is what I’m doing with these kefir grains accurately called brewing? After all, my sourdough starter also contains yeasts and lactic acid bacteria and SCOBY-knows-what other species of microorganisms, and yet, I don’t claim that I’m brewing sourdough.

First, of course, is the obvious link with brewing and drinking. I do not ever intend to drink my sourdough starter as I will the milk and juice I’m fermenting.

We use the term brewing to refer to two different modes of beverage preparation. Steeping tea leaves or ground coffee beans in hot water extracts molecules that impart taste, aroma, and the all-important stimulant properties of these beloved drinks. We call that brewing, but it’s a very different process from the complicated biologically active process that results in beer.

Unlike brewing coffee, brewing beer results in the formation of compounds not found in the original ingredients. Operating under near-medical conditions, with every piece of equipment sterilized and every stage of processing carefully executed to minimize the chance of contamination, beer brewers harness the fermenting power of one species of yeast to break down sugar — obtained by malting, crushing, and boiling barley — into carbon dioxide and ethanol. Unless the brewer is brewing a sour beer, bacteria are excluded from the process.

So yes, making kefir is a kind of sloppy brewing, with hand washed mason jars on a wiped-down kitchen counter and multiple species of yeast and bacteria contributing to the finished product. Avoiding the work of extracting sugar from malted barley, my SCOBY consume those already available in milk or juice. The yeasts will convert sugars into alcohol and carbon dioxide. Most of the alcohol produced will be converted into acetic acid (think vinegar) by bacteria, with other bacteria converting sugar directly into other weak acids. And so my kefir and tibicos should be lightly carbonated and a little sour with less than 1% alcohol content, which admittedly reads like the description of a really bad beer.

But when I sampled those first jars after brewing — 48 hours for tibicos and 24 hours for kefir according to my instructions — fermentation was minimally evident, the results being more reminiscent of flat pop and funky milk. What they were lacking, which all brewing requires, is time at some optimal temperature. After a weekend camping trip, the kefir and tibicos I’d abandoned had transformed into tart, effervescent beverages.

No time to dwell, my grains had to be fed more. And more. And so I cycled through a few gallons of milk for the kefir grains and a few gallons of various sugary concoctions for the tibicos. Cherry, black currant, and pomegranate syrups, dissolved coconut sugar, diluted maple syrup. When I read that tibicos is related to the SCOBY used to brew ginger beer in the Caribbean, I found my perfect match. Drinking all of the tibi I was making was easy.

Finding a use for all of the milk kefir was another story. My kefir grains are doubling in number every couple of weeks, and it quickly became evident that my two daughters didn’t like it straight, so I had to get creative. Our household production of pancakes and crepes went up. I poured it on porridge. But what else? Kefir smoothies and cheese seemed an obvious next move. I started leavening sourdough bread with it. Surely my cat can drink some of the excess? The suggested uses provided in the instructions I received with my order reassured me that I was not alone in my struggle to keep up with the kefir: kefir shaving lotion, face wash, shampoo, a kefir bath? Really? When I put kefir into a quart of pesto I made, I understood the magnitude of my problem.

In pre-refrigeration days, the value of kefir follows the same non-intuitive logic as all brewing and fermenting: knowingly inoculate your food with these harmless creatures that change it in safe, palatable and even healthy and enjoyable ways, or risk eating food contaminated with whatever happens to grow in it.

I’ll enjoy my river of kefir and appreciate the health benefits that traditional knowledge and science can attribute to drinking it.

But I will not take a bath in it.