Powdered buttermilk is made by removing all of the liquid from buttermilk. The dehydration process allows the buttermilk to be stored for a much longer time, but it has the same tangy flavor as fresh liquid buttermilk. To be considered powdered buttermilk, it must contain less than 5 percent moisture and more than 4.5 percent milk fat based on weight. You can use buttermilk powder the same way as you use liquid buttermilk in recipes.
Buttermilk and Buttermilk Powder
The buttermilk used to make powdered buttermilk is traditional buttermilk, not cultured buttermilk. This means it is made by dehydrating the leftover product produced from churning butter. Traditional buttermilk is a little less sour — although still quite acidic — than cultured buttermilk, and it is much thinner. It also has a creamier taste since it contains some of the richness of butter, although it is naturally low in fat. Buttermilk powder, when mixed with water, produces a liquid that is much thinner than cultured buttermilk, closer to that of traditional buttermilk.
Function of Buttermilk Powder
Even though it is not made from cultured buttermilk, which is produced by introducing bacteria to low-fat milk, powdered buttermilk can be used the same way cultured buttermilk is in recipes: It adds flavor, moistness and acts as a leavening agent. Buttermilk powder is most commonly used for baked goods such as biscuits or cakes, but it is also used for sauces and soups. Buttermilk powder will produce the same texture, taste and creaminess in baked goods as cultured buttermilk.
Using Powdered Buttermilk
Mix powdered buttermilk in with the dry ingredients for baked goods or, if you like, reconstitute it first. Add 1/2 cup of water to every 1 tablespoon of buttermilk powder, stirring to fully incorporate the powder. Let the mixture sit for a couple of minutes before using. You can also use buttermilk powder as a seasoning for fried chicken, in which you can add the dried powder directly to the meat without reconstitution. Reconstituted buttermilk powder is intended for cooking, not for drinking, as the texture is unpleasant. However, when added to oil and a creamy ingredient, such as sour cream, you can use it for salad dressings.
Storing Powdered Buttermilk
Powdered buttermilk lasts for much longer than the liquid, making it ideal for those who need buttermilk only on occasion. Store powdered buttermilk in a sealed bag or air-tight container in a cool, dry location — less than 81 degrees Fahrenheit — for 9 to 12 months. Storing it in high humidity can cause the powder to cake, and high temperatures can affect the taste of the powder. You can purchase powdered buttermilk in grocery stores and from bulk food suppliers.
References and ResourcesU.S. Dairy Export Council: Buttermilk Powder/Dry Buttermilk
Slate: All Churned Around
New York Times: Test Kitchen -- Buttermilk that Doesn't Go Plop-Plop
Bob's Red Mill: Buttermilk Powder Instructions
Darigold: Buttermilk Pancakes Using Buttermilk Powder