Buttermilk is great for adding tangy flavor and a lighter crumb to baked goods, but few people keep it on hand, particularly since it tends to be sold in quantities far larger than needed for most recipes. So Christa Walker of Raleigh, North Carolina, wondered whether kefir makes a good substitute.
Kefir is a fermented milk drink originally from the Caucasus, Russia and Central Asia. It has a thick, slightly effervescent consistency and mildly sour flavor.
Buttermilk, which has a similar taste, consistency and fat content, traditionally was the acidic liquid left behind when churning cream into butter. Today, most buttermilk is made similar to kefir—low-fat milk is fermented with lactic acid bacteria.
We suspected a one-for-one substitution would work, but to be sure we did side-by-side tests with biscuits, pancakes, yellow cake and cornbread. We also tested a common substitute for buttermilk—stirring 1 tablespoon white vinegar into 1 cup 2 percent milk and letting it sit for 5 minutes.
Not only did kefir work, we found the flavor and texture of those versions as good as or better than buttermilk in each case except for the cake, which was slightly denser but still had good flavor. The milk-vinegar mixture was worst in every case except the yellow cake; its one-note acidity failed to provide the rounder flavor of the cultured products.
Try this substitute in these Buttermilk Biscuits and see if you don’t start keeping kefir in your fridge.