Add the kefir grains and the eggshell, raisins, or aguamiel de maguey (if using), and then cover with a lid. Write the brewing date on a piece of masking tape on the outside of the jar.

While the plant-based revolution might have reduced the amount of lactose in our diets, certain dairy-based foods are making a comeback in the name of good health, and kefir is one of them.

Tim Spector, professor of genetic epidemiology at King’s College London and author of The Diet Myth: The Real Science Behind ... tastier than they sound. From kefir to kombucha and other ...

Place the kefir in a fine-mesh strainer, poised over a bowl, and cover it with a coffee filter. Let it sit for 2 to 3 hours to allow some of the whey to separate. Combine the garlic and onions in ...