Although buttermilk is not as popular as it once was, many recipes still call for it and it is still a key ingredient in many recipes. Buttermilk is a unique dairy product that provides a one of a kind flavor and plays an important role in the science of cooking.
Traditional or old-fashioned buttermilk is the liquid left over after churning butter. During the traditional butter making process, milk was left to sit, sometimes up to a day, to allow the butterfat to separate from the milk. During that time, bacteria naturally found in the milk would proliferate and ferment the milk’s lactose. Lactic acid, which is the byproduct of lactose fermentation, gives buttermilk its characteristic tangy flavor. Traditional buttermilk is still made in many countries throughout the world today.
In the United States, most buttermilk sold in stores is referred to as “cultured buttermilk.” This buttermilk is made from milk that has been homogenized to prevent the separation of milk fats and then pasteurized to kill dangerous bacteria. The milk is then inoculated with a specific mix of bacteria, or “culture”, to ferment the lactose. The use of specific cultures allows for consistency in flavor and texture.
Although most commercial buttermilks are made from either one or two percent fat milk, it has a thick texture more reminiscent of higher fat dairy products. The thick texture of buttermilk is due to lactic acid, which denatures the milk proteins and changes their shape and texture. For this reason, buttermilk can be used in place of higher fat milk products when a thick texture is desired.
Buttermilk is often used to add flavor to food. The lactic acid provides a sour, tart or tangy flavor, which is ideal for salad dressings, dips and baked goods. Buttermilk solids are used extensively in commercial foods to add flavor and body.
The lactic acid in buttermilk also plays a crucial role in the leavening process of many baked goods. When chemical leaveners, such as baking soda, are combined with an acid component, like buttermilk, the resulting chemical reaction produces gas. These gas bubbles provide leavening to many baked products like cakes, quick breads, and cookies.
Where to Buy Buttermilk
Buttermilk can be found in the refrigerated dairy section of most grocery stores. It is often sold in one-quart containers and is usually priced lower than fresh milk. The acidic pH of the buttermilk allows for a longer shelf life and therefore lower price. Traditional buttermilks can be found at ethnic markets, farmer’s markets, or local creameries.If buttermilk is unavailable to you, consult this list of Buttermilk Substitutions.