buttermilk is a term surrounded by much historical confusion. It originally referred to the liquid that drains away from butter after churning. This buttermilk was highly unstandardized in both appearance and flavor. It could be scanty and almost as thin as whey if made from rich cream, but plentiful and creamy if made from whole unhomogenized milk. (This counterintuitive result reflects the fact that cream contains more butterfat and less of everything else than milk.) Buttermilk can be almost flavorless if the milk is “sweet” (unfermented), or pleasantly sour if the milk has undergone some lactic acid fermentation, or “ripening.”
