It’s another way to ferment milk, using a kefir culture, known as kefir grains. Nutritionist Carrie Dennett explores a couple different ways to make it and shares her tips.

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On Nutrition

You likely know the benefits of yogurt for your gut microbiota, but do you know about kefir? Kefir is another way of fermenting milk that has more probiotics (beneficial microbes) than yogurt, often carrying twice as many bacterial strains along with some beneficial yeast strains. Bacterial diversity is good for your gut microbiota, which means kefir may have even greater benefits for gut health.

A kefir culture — known as kefir grains — is a community of microbes that form milky-white clumps that self-reproduce and grow over time (which means you can give some away to friends). Kefir cultures produce a thicker-than-milk, thinner-than-yogurt beverage that can be gently tart or quite sour. Sometimes it’s even bubbly. I’ve long used kefir in smoothies, in overnight oats and as a substitute for buttermilk in pancakes, waffles and biscuits.

According to Sandor Katz’s “The Art of Fermentation,” most commercially produced kefir is not cultured using actual kefir grains, mostly for logistical reasons. Kefir grains are complex, living things, which don’t lend themselves well to a consistent end product or reproduce fast enough to allow for the demands of large-scale production. Plus, kefir grains can produce beverages with a slight alcohol content, which presents a challenge commercially.

So how is that kefir in the dairy case made? With lab-produced starter cultures. The end result is a beverage that is also rich in beneficial microorganisms, but it’s questionable whether it should technically be called kefir. In my fledgling kefir experiments, I decided to try it both ways. I bought some freeze-dried kefir starter culture in the refrigerated section of my local PCC Natural Markets, and ordered some actual kefir grains from Yemoos Nourishing Cultures, based on a recommendation from another dietitian. I was pleased with both the grains and the how-to information on the Yemoos website.

Comparing methods

Using the live kefir grains could not have been easier. I removed them from the package, rinsed them in a plastic strainer with a bit of milk, then put them in a clean jar with a cup of milk, covered with a cloth secured by a rubber band, and let it sit on my counter. Roughly 24 hours later (time will vary based on room temperature), I strained out the kefir grains, then put them back in the jar with a fresh cup of milk to start my next batch.

To use the starter culture, I heated a quart of milk to boiling (repasteurizing it) before adding the cultures and allowing it to sit on the counter for 24 hours. With either method, if you aren’t ready to drink your kefir, put it in the refrigerator. For flavored kefir, try blending one cup of frozen berries with two cups of kefir. Delicious!

Pros and cons

The kefir grains are much easier to use, but they are more expensive and harder to get your hands on. However, they can be used over and over again if cared for properly. Once you use a packet of starter culture (there were six included), it’s done — which could count as a “pro” if you don’t want to make kefir regularly. Kefir grains, like all living things, need to be cared for — if you don’t use them regularly, they could die.

The general advice is to use raw or pasteurized — not ultrapasteurized — whole milk. Lower-fat milks also work, and it’s worth noting that kefir grains and cultures contain strains of yeast that feed on lactose. If you’ve wanted to try home fermentation, kefir is a low-effort way to test the waters.