Milk kefir is a fairly unique ferment in that it requires a special culture, known as grains. Despite the name, milk kefir grains are rubbery, irregularly-shaped blobs. They’re more similar to a Kombucha SCOBY or mother of vinegar than they are to a grain of rice or wheat. The grains can’t, as far as I know, be created spontaneously, and must be purchased or acquired from existing stock. I’ve had really good experiences ordering from these nice folks [aff], but plenty of people in fermentation groups are happy to supply you with grains for the cost of shipping.
Here are some grains I picked up recently, in a little bit of milk. Nope, the culture is not attractive, but I’m still a huge fan of the soured tonic it makes.
Where Does Milk Kefir Come From?
Historically, it’s thought that these cultures spontaneously developed in the Caucasus region during the early days of animal husbandry and dairy production. Storing fresh milk in the stomach of killed animals would have created an interesting mix of bugs. Microbiologically, the grains are created by a few dozen strains of yeasts and bacteria, giving it arguably the highest probiotic potential of any of the commonly made ferments.
Theoretically, milk kefir migrated with people, or similar cultures developed in different regions. The word “kefir” itself is thought to derive from the Turkish language, but this may be far more recent than the kefir culture itself.
What Does Milk Kefir Do?
Essentially, milk kefir grains are deposited into some kind of milk (more on this below) and left to ferment it for a day or two. Personally, I’ve found that using cheap store-bought milk seems to be a pretty frustrating exercise. Using better quality milk, even if it’s pasteurized, works fine. I prefer whole milk, but people seem to have adapted their grains even for skim milk. The organisms in the culture produce lactic acid, which sours the milk, and it thickens during the fermentation period as well. Milk sugars like lactose are consumed (to a greater or lesser degree, but probably not completely), and some effervescence is created by CO2 production. The end result has a sour, yogurty flavor, but is typically not as thick.
To harvest finished kefir, pour the result through a strainer, put the grains back into the jar (or a new jar), add more milk, and off you go. The straining can be a little tricky when the kefir has thickened substantially. A rubber or silicone spatula can help you press the milk through while retaining the grains. While metals are not recommended for contact with kefir, I doubt that a few minutes of contact has much effect if all you have is your normal aluminum strainer. Stainless steel is fine for acidic things like kefir.
Claims made about the effects of milk kefir are numerous, including that kefired milk may be acceptable for lactose intolerant people and that it can help with chronic conditions like asthma and allergies. As with any health claims garnered from the Internet, research thoroughly and skeptically.
Does Kefir Have To Be In Cow’s Milk?
Nope. While cow milk is the most common in the United States, kefir does very well in goat’s milk, if you have a source for that. Milk kefir works very well in raw milk and pasteurized, and again, my only caveat is that mine have always struggled when I went cheap on the type of grocery store milk I used. Organic, unfortunately for the price, really does seem to make a positive difference.
You can also culture milk kefir in non-dairy milks. I had great luck keeping a culture going for many months in organic canned coconut milk, of the sort you’d cook with. Using beverage style coconut milk apparently won’t work, with too few nutrients to sustain the culture. Lots of people have reported success with a variety of non-dairy milks, so kefir remains a healthy and flavorful option for vegans and those who avoid dairy.
Non-Dairy Milk Kefir Variations
In reading about milk kefir, I have come across the assertion over and over again that the culture feeds on lactose and can’t sustain itself on non-dairy milks for extended periods. This was not my experience though. My grains didn’t necessarily grow during the four or five months I used them exclusively in coconut milk, but they certainly didn’t degrade and die off. I never added sugars to the coconut milk either. Some sites suggest adding date paste for added sugars. Brewing shops sell bags of lactose [aff], which could theoretically be added if you want to play around.
I don’t know if my experience is unique or not, but my guess is that over time, the population of the culture shifts to emphasize organisms that consume fats and de-emphasize those that consume sugar. Purely speculation, but it would fit the facts of my coconut kefir days.
Keeping Milk Kefir Going & Taking Breaks
Maintaining a milk kefir culture can be plenty rewarding, but everybody needs a break from the grind sometimes. My breaks tend to stretch so long that my backups die, but the way to hit the pause button is to harvest your kefir, add fresh milk to your grains, and put them in the fridge. Check on them weekly. They will ferment in the fridge, but much more slowly and probably incompletely when compared to room temperatures.
I’ve heard of people freezing excess grains (they do reproduce) by putting them into powdered milk, then putting that in the freezer. In the internet age, it’s easy enough to track down fresh grains for a few dollars, so that’s been my approach, but of course, you get attached to these little guys and the miraculous job they do.
Drinking And Eating Milk Kefir
So what do you do with milk kefir? Plenty of people enjoy a glass of it straight up [raises hand]. Others mix it into smoothies or sauces. I’ve used it in salad dressings in place of mayo or yogurt, and I love the sour flavor. I also like using it in soup, especially something like hot and sour soup. It adds a real depth to the vinegar sourness, and adds a creamy texture as well.
If you have the equipment (I don’t), you can strain kefir to produce a variety of cheeses, from very soft to pretty firm. The liquid that strains out is whey, which is also very useful.
Seriously, milk kefir is good stuff, and I love to talk about it. Please leave a comment if I’ve missed any burning kefir questions. (Burning kefir is not recommended, however.)