A history of buttermilk MAY 11 2012
Turns out that "real" buttermilk, aka the byproduct of making butter, hasn't been common for almost a century...today it's been almost entirely replaced by cultured buttermilk.
So how did that buttermilk, the original buttermilk, turn into the thick, sour, yogurty beverage I sampled at Threadgill's? The confusion surrounding this drink dates back to the 18th century or before. Until the age of refrigeration, milk soured quickly in the kitchen, and most butter ended up being made from the slightly spoiled stuff. As a result, some historical sources use the word buttermilk in the Laura Ingalls Wilder sense, to describe the byproduct of butter-making; others use it to describe butter-making's standard ingredient at the time-milk that had gone sour from sitting around too long. To make matters more confusing, the butter-byproduct kind of buttermilk could be either "sour," if you started out with the off milk that was itself sometimes called buttermilk, or "sweet," if you started out with fresh cream (like Laura's mom did). So, prior to the 20th century, buttermilk could refer to at least three different categories of beverage: regular old milk that had gone sour; the sour byproduct of churning sour milk or cream into butter; and the "sweet" byproduct of churning fresh milk or cream into butter.
We occasionally get the real stuff for making the world's best pancakes and it definitely makes a difference.