Buttermilk is fermented milk. Traditionally, it was the liquid left behind after churning butter out of cultured cream, but most modern buttermilk is cultured. It is common in warm climates where unrefrigerated fresh milk sours quickly. Some recipes allow a substitute; others don’t (see buttermilk substitute).
Buttermilk is fermented milk. Traditionally, it was the liquid left behind after churning butter out of cultured cream, but most modern buttermilk is cultured. It is common in warm climates where unrefrigerated fresh milk sours quickly. Some recipes allow a substitute; others don’t (see buttermilk substitute).