Christensen explains how to make Milk Kefir, a sort of liquid yogurt. You don’t need any fancy equipment, just a canning jar, cheesecloth, and a strainer.
Once you master this basic recipe, you can add fruit and other flavorings to make mango kefir (mango and honey) or ginger-pear kefir (lemon juice, gingerroot, pears).
Christensen recommends buying kefir grains online at Cultures for Health.
Master Milk Kefir Recipe
(From Emma Christensen’s True Brews: How to Craft Fermented Cider, Beer, Wine, Sake, Soda, Mead, Kefir, and Kombucha at Home.)
Makes 1 cup
Think of kefir as liquid yogurt. It’s thicker than milk but not quite as spoonable as yogurt, though it tastes nearly identical. Kefir also has all the same healthy bacteria and probiotics as yogurt, with the added bonus of some yeast. This is all thanks to a few teensy little kefir grains, which will work tirelessly, batch after batch, to culture your milk. It should be noted that kefir grains do not actually contain any grain and are gluten free. Like the kombucha scoby, they are naturally occurring cellular structures of bacteria and yeast.
To increase the amount of kefir you make with each batch, just maintain the ratio of 1 cup milk to 1 teaspoon grains. After some time, your grains will start to multiply. You can split them to brew separate simultaneous batches of kefir, give them to a friend, or dry them for longer storage (see How to Put Your Milk or Water Kefir on Pause, page 59).
Note: Avoid prolonged contact between the kefir grains or the kefir and metal both during and after fermentation. This can affect the flavor of your kefir and weaken the grains over time.
1 cup milk (preferably whole, and avoid ultra-high temperature pasteurized milk)
1 teaspoon kefir grains
1-pint canning jar
Measuring cups and spoons
Cheesecloth or paper towels
Small fine-mesh strainer
Glass or plastic lidded container
Pour the milk into the glass jar and stir in the kefir grains. Cover the jar with a few layers of cheesecloth or paper towels and secure with a rubber band.
Store the jar at room temperature out of direct sunlight and allow it to ferment until thickened. Healthy kefir grains at around 70°F will typically culture in 24 hours, though it may culture in as little as 12 hours at warm temperatures, or take as long as 48 hours at cooler temperatures. Check the kefir periodically until you have a sense of how quickly it is fermenting.
Strain the kefir into a glass or plastic storage container, stirring gently until just the grains are left in the strainer. Refrigerate the kefir in a sealed container and use within 2 weeks. Stir your grains into a new jar of milk to make another batch of kefir.