Photo by Adobe Stock/Dušan Zidar
Likely originating in the Caucasus Mountains, milk kefir grains are a symbiotic culture of bacteria and yeast (SCOBY) that ferments milk. To make milk kefir, you must acquire a tablespoon or so of these milk kefir grains, which look like cottage cheese or small cauliflower florets. If you buy dehydrated grains, follow the instructions on the package to rehydrate them. Either way, you’ll need a large glass or ceramic jar — Mason jars are ideal. Be aware that you’ll need an inch or two of headroom in the jar above the fermenting milk, because kefir needs air while it’s fermenting. If there’s any question about what size jar to use, go larger rather than smaller.
The milk kefir culture feeds on lactose, so it won’t work with lactose-free milk. Fresh, raw milk is best, because it contains lots of beneficial bacteria and enzymes of its own and will make a more biologically diverse kefir. Make sure the milk is no more than a day old; otherwise, the enzymes and microbes that naturally occur and multiply in raw milk can start to dominate the kefir microbes and send things in an unexpected direction. This can result in a funky-tasting kefir and possibly a biological drift in the kefir grains, making them less effective in the future. Regular pasteurized milk works fine too, or high-pressure processed milk, but the same rule applies: The fresher the milk, the better.
Kefir ferments best at room temperature or warm room temperature. This makes it even easier and more convenient to make than yogurt, because it doesn’t require an elevated temperature, nor does it require the milk to be heated ahead of time.
Also, because kefir cultures tend to be “wilder” than yogurt cultures in the sense that they contain more unknown strains of microbes, it’s harder to generalize about starter ratios, ideal temperatures, and times. For this reason, if you want to get consistent results, you may need to keep track of these parameters for yourself in a notebook, or at least settle into a consistent routine and be conscious about varying it.
Flavor Your Milk Kefir
If you’d like some variety, add flavors, such as vanilla or cinnamon, to your kefir right before drinking it, as you would when flavoring coffee. You can also add fruit for a secondary fermentation at room temperature with a sealed lid. For every 1 cup of kefir, try 1⁄2 cup of fruit. Add the fruit to the kefir, and then let it sit for up to a day at room temperature. After it’s ready, strain, if you’d like, and then refrigerate.
Milk Ferment Variations
Milk kefir grains can be used to culture coconut water or coconut milk, fruit juices, and nut milks. If you want to do this, alternate batches with milk, because dairy kefir grains need lactose on a regular basis to remain healthy, and lactose is found only in dairy milk. Two or three batches of dairy milk per batch of other liquids should do the trick. Fresh is better than canned or boxed. Juices are easy to make with fresh, seasonal fruits. Just substitute 2 cups coconut water, coconut milk, fruit juice, or nut milk for dairy milk, and rinse the dairy kefir grains well with filtered water before beginning. Then, proceed as you would with dairy milk.
- 1 tablespoon dairy kefir grains
- 2 cups whole dairy milk, raw or pasteurized
- Place the kefir grains in a quart Mason jar, and pour the milk over them. If you’re scaling up the recipe, scale up the jar too. Stir vigorously with a wooden or plastic spoon if necessary to get things mixed well. Seal with an airtight lid, or, if you don’t have any other SCOBY brews in the room, cover the top with a clean cloth, kitchen towel, paper towel, or coffee filter, and secure with a rubber band or Mason jar ring. Agitate the milk mixture. Write the brewing date and time on a piece of masking tape and stick it to the outside of the jar.
- Let the kefir sit at room temperature for 12 to 24 hours. The first few times you make it, you may want to taste it to decide when it’s done. It should be thick, sour, and somewhat yeasty. If milk kefir is left to ferment for long enough, it’ll separate. You’ll see curds and whey. This kefir will be very sour, and may be past its prime for drinking, but it’s still fine for smoothies, salad dressings, and so on.
- Pour the kefir through a plastic or nylon strainer into a bowl or jar. Straining milk kefir can be confusing and stressful at first, because the acidity of the kefir can cause the milk to curdle and the proteins to coagulate more and more as it ferments. If you’re having trouble distinguishing kefir grains from coagulated milk, don’t hesitate to use your (clean!) fingers to pick through the globs, shake the strainer, or stir the grains in the strainer gently with a wooden or plastic spoon. Kefir grains will be firm to the touch, while the other pieces will not resist when you squeeze them. If necessary, you can pick out the kefir grains with your fingers, or push the curdled milk globs through the strainer. Metal strainers and spoons are not recommended for this, because they can cut the grains, making it harder to distinguish the grains from the kefir itself.
- Your kefir is ready! Serve it now, or, if you prefer it cold or want to save it for later, cover and refrigerate it.
- Transfer the kefir grains from the strainer to another glass or ceramic jar and start a new batch with them immediately, if possible. If you’re not going to use your grains right away, store them in fresh milk in the refrigerator, covered, where they’ll keep for weeks.
Learn more about kefir here.
Alex Lewin and Raquel Guajardo teamed up to share their fermenting knowledge through the written word. This is excerpted from their book Kombucha, Kefir, and Beyond (Fair Winds Press, an imprint of The Quarto Group).