What is Buttermilk?

Two different dairy products carry the name buttermilk, depending upon where in the world the consumer is. Traditional or old fashioned buttermilk is the liquid left over after churning butter, and it is popular in India and Southeast Asia. Cultured buttermilk, the product commonly found labeled with this name in American supermarkets, is a fermented milk product. In both cases, it is creamy and rich, and both varieties can be drunk directly or added to baking projects.

Old fashioned buttermilk is far thinner than cultured and tends to be paler and more acidic than conventional milk. It is created when butter is churned. Traditionally, farms would skim cream from the top of fresh milk and collect it in a vat for churning. Several days would often go by before there was enough cream to churn into butter, and as a result, it would sour slightly. Slightly soured cream is easier to churn and lends a specific flavor to butter that some consumers prefer.

After churning, the butter was removed and washed in cold water to remove the excess milk before being salted for preservative purposes. The liquid remaining in the churn after the butter was removed came to be called “buttermilk” and was characterized by being rich, acidic, and sour in flavor, often with flakes of butter floating in it. This sour, creamy beverage is drunk in many parts of the world, although it is difficult to obtain in the United States.

Cultured buttermilk is created by fermenting milk so that milk sugars turn into lactic acid, causing milk proteins to become solid, as they are no longer soluble in more acidic conditions. This results in chunks of material and a thicker milk, called clabbering. The beverage is also more tart than regular milk because of its increased acidity. Buttermilk can last longer than regular milk, because the acidic conditions keep harmful bacteria from thriving. Sour cream is created using a similar process, using cream instead of milk during the fermentation.

Many bakers use cultured buttermilk in scones, biscuits, pancakes, and other similar products because of the tangy flavor it imparts. Consumers need to be careful with it, because it is a soured product. Although harmful bacteria should not be able to thrive in it, if the flavor is slightly off, it is better to dispose of the buttermilk than to experience minor gastrointestinal distress as the result of stray bacteria or molds.