Question: are buttermilk and sour milk the same thing?
Answer: Sour milk is not the same as buttermilk. Buttermilk is either purposefully cultured to get a sour taste or is the byproduct of butter making. If raw milk sours, it's perfectly fine to drink and that's the way most of the world drinks milk. But if pasteurized milk sours, it's just on its way to going bad.