Homemade buttermilk is a lifesaver and eliminates waste. Two ingredients and 10 minutes and you'll be making buttermilk pancakes, waffles, whatever!
You don’t need to be ultra precise here, these are rough measurements.
Use freshly squeezed lemon juice (or white vinegar), add to milk, stir, and let sit for 5-10 minutes or up to an hour. You will start to see a few curds forming on top of the milk, they will not be noticeable in your baked goods.
Homemade buttermilk does not store well, toss whatever you don’t use within an hour.