Buttermilk is a fermented dairy product.
Most modern buttermilk is cultured, meaning that beneficial bacteria have been added to it. It’s different from traditional buttermilk, which is rarely found in Western countries today.
This article refers to cultured buttermilk simply as buttermilk.
This dairy product is most often used in baking. For example, it’s a common ingredient in biscuits, muffins, quick breads, and pancakes. It can also be used in batters for fried foods or as a creamy base in soups, potato salad, or salad dressings.
This article reviews the nutrition, benefits, and downsides of buttermilk and tells you how to make substitutes for store-bought varieties.
What is buttermilk?
The name buttermilk is somewhat misleading, as it doesn’t contain butter.
Traditional buttermilk is the liquid leftover after whole milk has been churned into butter. This type of buttermilk is rarely found in Western countries today but remains common in parts of Nepal, Pakistan, and India.
Buttermilk today consists mostly of water, the milk sugar lactose, and the milk protein casein.
It has been pasteurized and homogenized, and lactic-acid-producing bacteria cultures have been added, which may include Lactococcus lactis or Lactobacillus bulgaricus.
Lactic acid increases the acidity of the buttermilk and prevents unwanted bacterial growth, which extends its shelf life. It also gives buttermilk its slightly sour taste, which is a result of the bacteria fermenting lactose, the primary sugar in milk
Buttermilk is thicker than milk. When the bacteria in the beverage produce lactic acid, the pH level is reduced, and casein, the primary protein in milk, solidifies.
When the pH is reduced, the buttermilk curdles and thickens. This is because a lower pH makes the buttermilk more acidic. The pH scale ranges from 0 to 14, with 0 being the most acidic. Cow’s milk has a pH of 6.7–6.9, compared with 4.4–4.8 for buttermilk.
