FIRST, A WORD ON NONFAT, LOW-FAT, AND WHOLE BUTTERMILK
Buttermilk first originated as the portion left behind after butter had been churned from whole milk. Since the fat was removed as butter, the milk left behind was essentially low-fat or nonfat. Natural cultures would then take over, souring the buttermilk and creating its characteristic flavor. Today, most commercial buttermilk is cultured, similar to yogurt, by adding microorganisms to nonfat, low-fat, or whole milk.
When it comes to whole buttermilk, the higher fat content may lead to a richer product; however, buttermilk is most often chosen for baking for its high acidity. Acids react with baking soda in recipes, causing carbon dioxide production and subsequent leavening of baked goods. Thus, low-fat and whole buttermilk can often be used interchangeably without great differences in the final product. We often see whole buttermilk in the southernmost states of the US, but if you are unable to find whole buttermilk, substitute with low-fat buttermilk or one of the substitution recipes below.
Nonfat buttermilk, as it reads, does not contain fat. In baking, you will most often see recipes calling for low-fat and whole buttermilk rather than their lean counterpart. When you remove fat completely from buttermilk, the acid from the buttermilk is front and center and may cause curdling in egg-based recipes, such as custards. When using low-fat and whole buttermilk, the available fat acts as a buffer by coating egg proteins, making them less likely to form lumps and clumps. Be leery when substituting nonfat buttermilk for low-fat or whole buttermilk, especially with egg-based recipes.
Don’t let a lack of buttermilk sour your baking plans. Some resourceful replacements could save the day. Buttermilk is favored for the tenderness and tang it gives baked goods. But for times when you’re out, give one of the following swaps a try.
MILK + LEMON JUICE
¾ cup plus 3 tablespoons (225 grams) whole milk + 1 tablespoon (15 grams) fresh lemon juice or white vinegar = 1 cup (240 grams) buttermilk. Let stand for 5 minutes before using.
PLAIN WHOLE YOGURT + WATER
¾ cup (180 grams) plain full-fat yogurt + ¼ cup (60 grams) water = 1 cup (240 grams) buttermilk. The amount of water needed to achieve buttermilk consistency may vary depending on thickness of yogurt.
1 cup (240 grams) kefir = 1 cup (240 grams) buttermilk
GREEK YOGURT + WATER
⅓ cup (80 grams) whole milk plain Greek yogurt + ⅔ cup (160 grams) water = 1 cup (240 grams) buttermilk
SOUR CREAM + WATER
½ cup (120 grams) sour cream + ½ cup (120 grams) water = 1 cup (240 grams) buttermilk