What is buttermilk?
Essentially, buttermilk is fermented milk. Originally, buttermilk was
the leftover liquid produced following the churning of cream into
butter. When butter was made at home, that leftover liquid was left out
overnight to ferment. Modern buttermilk is now made by adding lactic
acid-producing bacteria to milk (usually low-fat milk) to ācultureā it
in a controlled environment. The acid affects the casein proteinsā
ability to come together by lowering the pH of the milk, and thatās what
produces the thick texture of buttermilk. Buttermilk is used primarily
for its pleasant tangy flavor, but it can also help tenderize and leaven
certain baked goods.
Learn more on Wikipedia
