Kefir (pronounced KEE-fur or Kay-FEAR, depending on your preference) is a drinking yogurt that is bursting with probiotics. In the past few years, it has become a grocery store staple here in the US, but it is ridiculously easy to make yourself. Besides the obvious cost benefits, there are the added benefits of DIYing, such as choosing the quality of milk you want, knowing your bacteria are the real, live deal and making whatever “flavors” suit your palette.
There are a couple of tiny hurdles to overcome before you make kefir. First, you need kefir grains. If you don’t know a hippie or a fermenter, you can order them online. I got some from Cultures for Health to test them, and after rehydrating, they worked just like the grains I got from a fellow fermenter. GEM Cultures sells fresh grains that also work like a charm, without the pesky need to rehydrate them. I like the idea of getting them from a person, because it creates community and as any kefir maker knows, you will eventually have way too many grains to know what to do with, even after you make a batch dedicated to kefir sour cream and try some in non-dairy milks and unpasteurized juices. So getting them from a friend prevents waste, too!
Second, kefir grains and metal don’t mix! [See note at the end of this post for a mea culpa]. Although minimal contact with metal won’t harm your grains, storing them in metal containers or fermenting kefir in metal containers could be an issue. I use glass mason jars. You certainly do not need to use a mason jar to make your kefir. I’ve used everything from half-gallon glass milk jugs to pyrex bowls. The only important thing is that you are able to easily secure a cover to your container.
Third, the most important variable here is temperature. Your grains will kefir best at room temperature. Below room temp, fermentation will get very slow which isn’t super for milk kefir. Above room temp, it will kefir too fast which can throw the balance of your bacteria and yeast out of whack. It’s best not to leave your grains in for longer than 24 hours. If your milk hasn’t kefired by then, strain out the grains and discard the milk. Try again. I have literally never once had this happen, but in colder months, I’ve had to wait a full 24 hours for a batch to complete.
How-To Make Milk Kefir
1 Tablespoon of kefir grains
1 quart of your preferred milk
- Put kefir grains in container
- Attach covering
- Move container to a room temperature spot out of direct sunlight
- Gently agitate when you remember to
- When milk is thickened (anywhere from 12-24 hours later) and smells a bit yeasty, strain the grains out of the kefir, put them into fresh milk, and stick the grain-free kefir into the fridge
- Begin process again*
*If you have made enough kefir, you can keep your grains stored in milk in the fridge for up to a week before starting your next batch. Even at the low fridge temperature, the milk will kefir, albeit very slowly, so be sure to start your post fridge batch at a time when you will be able to watch closely.
**This post has been updated to reflect my better understanding of how metal and grains interact. When I wrote this post in 2012, I thought that even touching metal could harm grains (based on lots of things I had read, and talking to other fermenters). In the years since, I’ve tested this theory with spare grains and I have officially debunked it for my home kefir-making. Having said that, storing your kefir or grains in a metallic container is still problematic. The grains produce acid, acid corrodes metal and corrosion isn’t something you want to consume.**