I first saw the word buttermilk in print while reading Laura Ingalls Wilder’s Little House in the Big Woods. In one riveting scene (I was 7 years old) Laura’s mom dyes some cream yellow with grated carrot and then churns it into butter. After shaping and embossing the butter, she takes the leftover liquid from the churn and gives Laura and her sister “each a drink of good, fresh buttermilk.”
This whole process—and especially the celebratory buttermilk quaff—stuck with me, as exotic images from literature tend to do when one is a child. So when I saw buttermilk on the menu at a Southern-themed restaurant called Threadgill’s a few months later, I promptly ordered a glass. My parents advised me to reconsider, but I persevered: This was a chance to commune with my favorite author and to prove to my parents that I had a hardy, advanced palate. (My ability to enjoy a glass of buttermilk at the age of 7 carried the same symbolic weight that my ability to enjoy a scotch neat does today.)
My parents were right. The buttermilk was sour, tart: awful. So overwhelmingly acidic was its flavor that I hardly even noticed the creaminess. I abandoned the glass after one sip.
Where had I gone wrong? My mistake was assuming that the buttermilk I had ordered would be the same kind of buttery buttermilk that Laura Ingalls Wilder had drunk in the late 19th century. This was a bad assumption. What we call buttermilk today has nothing at all to do with butter. In fact, the stuff known as cultured buttermilk at your local supermarket—i.e. milk that has been deliberately soured—is a 20th-century invention, and the product of a health-food diet craze dating back to the flapper era.
“As long as people have made butter there's been buttermilk,” says Anne Mendelson, a culinary historian and the author of Milk: The Surprising Story of Milk Through the Ages. Careful: Here, she’s talking about a byproduct of churning whole milk or cream—the thin, white liquid that Wilder wrote about.
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.
Few people in the English-speaking world cared very much about this lack of clarity. In Western Europe and America, the only people who bothered to drink buttermilk of any kind were the poor farmers and slaves who needed all the calories and nutrition they could get. Everyone else fed sour milk and butter-byproduct to their farm animals. We know from accounts recorded for the Federal Writers’ Project of the WPA that American slaves sometimes drank butter-byproduct buttermilk “slopped into hog troughs, maybe with some stale cornbread thrown in,” according to Mendelson.
By the late 1800s, buttermilk had taken on a more specific meaning and usage in the kitchen. Cookbooks started calling for the sour version of buttermilk in recipes for bread made with baking soda. Church & Co., the company that would later create the ubiquitous Arm & Hammer label, first started processing and packaging sodium bicarbonate as baking soda in 1846. The new product was more reliable and faster to use than yeast, but it wouldn’t work unless mixed with an acid. In the 1860s, Church & Co. began distributing instructions for making baking-soda cornbread, biscuits, muffins, pancakes, and waffles—and it recommended the use of sour milk as an activator. “The farmer’s wife has always an acid free to her hands in the shape of sour milk or buttermilk, which can be used both as an acid to neutralize the Soda or Saleratus [an old-fashioned word for baking soda], also as a means of wetting the dough,” stated a 1900 edition of the booklet. (“Sour milk” and “buttermilk” may be meant as synonyms here.)