Buttermilk can also refer to a fermented dairy product produced from cow's milk. The process to make buttermilk is
1. Turned the milk into curd
2. After that churned the curd to produce buttermilk.
It is slightly sour in taste. It color ranges from white to pale yellow. Buttermilk is lower in fat and high in potassium, vitamin B12, calcium, and riboflavin as well as a good source of phosphorus. It can last up to 2 week.