June 5, 2014 at 1:00 am

Learn to make your own probiotic-packed milk kefir

Over time, Kefir milk grains will multiply. (Emma Christensen)

Milk kefir is a fermented dairy product similar in many ways to yogurt and buttermilk. All you need to make milk kefir is milk and kefir grains.

Kefir grains are not really grains at all (donít worry, gluten-free folks!). These ďgrainsĒ are actually tiny, rubbery, knobby-looking cell structures that are home to the bacteria and yeast that ferment the kefir. These grains are the milk kefir equivalent to the scoby used to make kombucha.

Like yogurt and other cultured and fermented products, milk kefir is full of probiotics, which aid healthy digestion. The fermenting process also changes some of the protein structures in the milk, making it easier to digest.

You can drink milk kefir just as it is, straight-up. You can also add milk kefir to smoothies, lassis, and other drinks, just as you would use yogurt or regular milk. Kefir is fantastic for baking, too; use it in place of yogurt, milk or buttermilk in any recipe you make.

How does milk become kefir?

Itís extremely simple. Add about a teaspoon of these kefir grains to a cup of milk in a clean glass jar (not metal), cover the glass with cheesecloth, a paper towel, or a clean napkin and secure it with a rubber band, and let it sit out at room temperature away from direct sunlight for 12 to 48 hours. Check the jar every few hours. When the milk has thickened and tastes tangy, itís ready.

If your milk hasnít fermented after 48 hours, strain out the grains and try again in a fresh batch (this sometimes happens when using new kefir grains, refreshing dried kefir grains, or using grains that have been refrigerated).

Place a small strainer over the container youíll use to store the kefir. Strain the kefir into the container, catching the grains in the strainer. As long as they stay healthy, you can reuse kefir grains indefinitely to make batch after batch of kefir. And the best way to keep them healthy is to keep making kefir! You can make a new batch of kefir roughly every 24 hours (the temperature of your kitchen can affect the exact time) just by putting the kefir grains in a fresh cup of milk. Over time, the grains will multiply and you can either discard the extra or share it with friends. You can also take a break from making kefir by putting the grains in a new cup of milk and storing this in the fridge.

When done fermenting, the kefir will have thickened to the consistency of buttermilk and taste noticeably tangy, like yogurt. The prepared milk kefir can be used or drunk immediately, or covered tightly and stored in the refrigerator for up to a week.

What milk to use

The kefir grains work best with whole-fat animal milk, which is to say, whole-fat milk from cows, goats and sheep. You can successfully make kefir with 2 percent and reduced-fat milk, but if you notice that your grains are behaving sluggishly or taking longer and longer to ferment the milk, pop them back in a jar of whole milk to refresh them. You can also use raw or pasteurized milk, but avoid ultra-high temperature (UHT) pasteurized milk.

If youíre looking for a nondairy option, try making the kefir with coconut milk. Since coconut milk lacks the same proteins and nutrients as animal milk, the kefir grains will lose their vitality after a little while. To refresh them, put them back in some animal milk for a batch or two. Unfortunately, I havenít had success with making milk kefir with almond milk, soy milk or other dairy-free milks.

Where to find kefir grains

The best place to find kefir grains is from a kefir-making friend! The grains start to multiply after a while and anyone who makes it regularly will have extra grains to spare. If you donít have such a friend, I recommend buying them online from Cultures for Health ó $18 for dried kefir grains that need to be rehydrated before using. (Rehydrate them by soaking them in fresh milk at room temperature. Change the milk every 24 hours until the grains begin to culture the milk and make kefir. It may take 3 to 7 days for the kefir grains to become fully active.)

Recipe notes

Kefir/metal contact: Avoid prolonged contact between the kefir and metal both during and after brewing. This can affect the flavor of your kefir and weaken the grains over time.

Activating dried kefir grains: If you bought your kefir grains in a dried form, rehydrate them by soaking them in fresh milk at room temperature. Change the milk every 24 hours until the grains begin to culture the milk and make kefir. It may take 3 to 7 days for the kefir grains to become fully active.

What milk to use: Kefir works best with whole-fat cow, goat, sheep or other animal milk. You can use low-fat milks, but refresh the grains in whole-fat milk if they stop fermenting the kefir properly. Raw and pasteurized milks can be used, but avoid ultra-high temperature (UHT) pasteurized milks.

Making more or less kefir: Youíll need about a teaspoon of grains to ferment 1 to 2 cups of milk. You can also ferment less milk than this, but fermentation will go more quickly. Your grains will start to multiply over time, allowing you to ferment more milk if you like. Maintain a ratio of about a teaspoon of grains to 1 cup of milk.

Taking a break from making kefir: To take a break from making kefir, transfer the grains into a fresh container of milk, cover tightly, and refrigerate for up to a month.

What to do if your kefir separates: Sometimes kefir will separate into a solid layer and milky layer if left too long. This is fine! Shake the jar or whisk the kefir to recombine and carry on. If this happens regularly, start checking your kefir sooner.