Buttermilk

Buttermilk is a tangy cultured dairy liquid with a slightly thick, creamy body. Its acidity tenderizes batters and doughs, helping pancakes, biscuits, and quick breads rise fluffy. Use it for marinades, dressings, and dredges for frying; it also blends smoothly into smoothies and chilled soups. Sold as cultured, usually low-fat; acidified versions are common in retail.

Traditional buttermilk was the tangy liquid left after churning cultured cream across Europe and South Asia. Modern cultured buttermilk became standard in North America in the 20th century, produced by fermenting low-fat milk with lactic cultures and now common in Southern cooking and commercial baking.