Can You Always Substitute Kefir for Buttermilk?

A Milk Street Radio caller asked, “Can you always use kefir instead of buttermilk in recipes, or are there occasions when you should really use buttermilk?”

The short answer is yes, more or less.

We’ve previously found that kefir worked well as a substitute in baked goods, though they sometimes were slightly denser than buttermilk versions.

The flavor difference was more challenging. Both kefir and buttermilk are fermented dairy products, but kefir is made with a more complex fermentation process involving a broader range of bacteria and yeasts, which results in a sharper, more pronounced tanginess, as well as a thicker and creamier consistency.

Testers consistently described kefir as having a "sour, grassier flavor" with noticeable tanginess that varied in intensity depending on the application. This flavor difference was most pronounced in the fried chicken and cornbread, where it created an undesirable "gaminess" and "grassy aftertaste" that detracted from the intended flavors.

Application-Specific Results:

• Pancakes: Kefir performed best here, with minimal flavor impact and only slightly thicker batter. The conclusion was that kefir works well as a buttermilk substitute in pancakes.
• Fried Chicken: The flavor difference was most problematic in this application. Testers preferred the "cleaner, more chickeny flavor" of the buttermilk version.
• Cornbread: Kefir produced inferior results across multiple metrics - worse rise, browning, and a "gummier mouthfeel" that testers found unappealing.
• Pie: In blind tasting, buttermilk was preferred for its "sweeter, milder flavor" and creamier texture, while the kefir version had distinct sourness.

Technical Observations:

Kefir consistently produced thicker batters than buttermilk, though this didn't always translate to noticeable differences in the finished products. Browning patterns also varied, but not consistently - sometimes kefir produced more browning (pie), sometimes less (cornbread).

Bottom Line:

While kefir can technically substitute for buttermilk in most recipes, the results show it's not an ideal replacement due to its distinctive sour, grassy flavor profile. The substitution works best in applications where other flavors can mask kefir's tanginess (like pancakes) but performs poorly when the dairy component plays a central role in the dish's flavor profile. Cooks considering this substitution should be prepared for noticeably different results.