It’s quite simple to make your own sour cream, with just two ingredients: heavy cream and milk kefir.

I first made this as a way to enjoy cultured ice cream, but realized the taste, texture and consistency are just like sour cream (which is also easy to make). Use it on porridge, stir into hot cocoa, make kefir ice cream, or make party dips with it! It will be slightly runnier than commercial sour cream (which typically uses thickening agents like powdered milk, gums or other stabilizers).

There is enough bacteria and yeasts in finished kefir to inoculate the cream, without even adding the kefir culture (“grains”). This is handy because if you use kefir grains, it’ll be harder (but not impossible) to fish them out once the cream thickents. I recommend this method with homemade kefir only (because I haven’t used any store-bought kefir brands). If you have done this successfully with commercial kefir, please drop us a line in the comments!

You can “stop the sour train” whenever you’d like. You can make it mild or super sour by simply letting it go shorter or longer.

For the cream, if you don’t have access to your own cow, buy the best quality heavy cream you can afford. Raw milk works best (if it’s legal in your state). If that’s not in your area or your budget, then grass-fed, low temperature pasteurized heavy cream is next best. The better brands usually come in glass bottles. Avoid “ultra-pasteurized” or “UHT” pasteurized, as they have been zapped of some of the nutrients that the bacteria use to thrive.

Typically it takes 24-36 hours at room temperature, maybe longer if it’s cooler. Ideal fermentation temperature is about 75°F/24°C. Stir it once or twice, and taste it. When you like its thickness and its sourness, it’s done! It should also increase in volume slightly.