How To Make Milk Kefir
Kefir is tangy, about as thick (and creamy!) as a smoothie, and full of those good-for-you probiotics we hear so much about. Think of milk kefir as drinkable, pourable yogurt.
Makes 1 cup
1 cup milk, preferably whole fat (see Recipe Notes)
1 teaspoon active kefir grains (See Recipe Notes)
1 pint-sized glass jar
Cheesecloth, paper towel, or clean napkin
Small strainer (preferably plastic, but metal is ok)
Storage container with lid
Note: 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.
Combine the milk and the grains in a jar: Pour the milk into a clean glass jar (not metal) and stir in the kefir grains. The milk can be cold or room temperature, either is fine.
Cover the jar: Cover the jar with cheesecloth, a paper towel, or a clean napkin and secure it with a rubber band. Do not screw a lid onto the jar as the build up of carbon dioxide from the fermenting grains can cause pressure to build in the jar, and in extreme cases, cause the jar to burst.
Ferment for 12 to 48 hours: Store the jar at room temperature (ideally around 70°F) away from direct sunlight. Check the jar every few hours. When the milk has thickened and tastes tangy, it’s ready. This will usually take about 24 hours at average room temperatures; the milk will ferment faster at warmer temperatures and slower at cool temperatures. If your milk hasn’t fermented after 48 hours, strain out the grains and try again in a fresh batch (this sometimes happens when using new kefir grains, when refreshing dried kefir grains, or when using grains that have been refrigerated).
Strain out the kefir grains: Place a small strainer over the container you’ll use to store the kefir. Strain the kefir into the container, catching the grains in the strainer.
Transfer the grains to fresh milk: Stir the grains into a fresh batch of milk and allow to ferment again. This way, you can make a fresh batch of kefir roughly every 24 hours. To take a break from making kefir, place the grains in fresh milk, cover tightly, and refrigerate.
Drink or refrigerate the milk kefir: The prepared milk kefir can be used or drunk immediately, or covered tightly and stored in the refrigerator for up to a week.
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: You’ll 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.