What Can I Substitute for Buttermilk in a Cake?

Good Questions

Q: I live in Colombia South America, and I am doing a cake for my birthday, which is in two weeks. I am doing an inside-out Black Forest cake from Martha Stewart.

But we don't have buttermilk so I would like to know if I can replace with a type of fermented milk called Kumis.

Sent by Angela

Editor: Tara, our hunch is that your Kumis is similar to kefir, which does make a good (yet tangier) substitute for buttermilk. If you want to be sure, though, you can just use regular milk and mix it with a tablespoon of vinegar and let it stand for five minutes before using it in your recipe.

Readers, any more advice for Tara?

Related: Food Science: What is Buttermilk?

(Image: Martha Stewart)