There are times when you decide to buy buttermilk, and then there are times when you just don't feel like committing to purchasing a whole quart when your recipe only calls for half a cup. You opt to make it at home — by adding vinegar to milk — but it never gets quite as thick as the buttermilk you buy at the grocery store. If you've ever questioned whether or not this shortcut makes a difference, here's what you need to know.
Traditional Buttermilk Comes from Butter-Making
Real buttermilk used to be prepared from the milk left over from the butter churning process. The milk was left to stand at room temperature to naturally separate the fatty cream layer from the watery milk before churning that cream into butter. Since the milk was raw, the bacteria present gave buttermilk its distinctive sour flavor and thicker texture the longer it was stored. Traditional buttermilk was often flecked with little bits of fat.
Commercial Buttermilk Is Cultured Milk
Since the early 19th century, dairy producers use centrifugal separators that separate the milk and cream much faster, allowing producers to bypass all that time waiting for the cream to separate from the milk. The resulting milk layer lacks buttermilk's signature fermented tang. Furthermore, with the advent of pasteurization, the microorganisms that would normally contribute to flavor development and thickening of buttermilk are destroyed.
Today, producers resort to spiking the milk with lactic acid-producing bacteria to transform the milk into a dairy product that is closer to true buttermilk. This is why you have probably noticed that the buttermilk sold in stores today is usually labelled as "cultured," just like yogurt.
Homemade Buttermilk Is Actually "Soured Milk"
A common way of making buttermilk at home is to add an acid — namely vinegar, which is about 5 percent acetic acid — to milk, and letting it sit for several minutes to curdle. Unfortunately, given the limited quantity of vinegar that you can add without negatively affecting flavor, the milk can only get so thick. Homemade sour milk is indeed much thinner than commercial buttermilk and tends to have a vinegary taste. While soured milk works in a pinch, it doesn't compare to cultured buttermilk, which is thick, smooth, and tangy, but not vinegary.
Have you noticed a difference in your cooking and baking between commercial cultured buttermilk and the quick buttermilk substitute you can make at home?