Making your own buttermilk is entirely too easy to not share. I honestly don’t see a point in purchasing buttermilk when you can easily make your own.
Buttermilk is something I never have on hand. An easy trick to make your own buttermilk is to place the milk in the proper measuring cup leaving a tiny bit of room at the top. Add 1 tbsp. of white vinegar and let sit for 2-3 minutes. (If making more than 2 cups add 1 tbsp. per cup of vinegar) A layer will separate on the top of the milk beginning the process of turning the milk into buttermilk.