Buttermilk 101

It’s funny to think that buttermilk is neither butter nor milk, and that the milky ingredient we use for baking, dressings, or marinades doesn’t actually have any butter in it. Back in the day, this was not the case. Way back when, buttermilk was the leftover liquid after butter was churned—get it? Butter-milk. Naturally occurring bacteria would cause fermentation pre-churning, making the buttermilk slightly thicker and acidic. Nowadays, it’s made commercially by purposefully adding a certain type of bacteria (and often thickeners as well) to nonfat or low-fat milk to produce cultured buttermilk. This process gives buttermilk the familiar thickened texture and tangy flavor we all know and love.

In baking, buttermilk does wondrous things. When used alongside baking soda, it helps batters and doughs rise by creating carbon dioxide. It also helps tenderize baked goods, giving them a soft, fluffy texture, and not to mention that irresistible, yet subtle tang. Buttermilk is also often found in savory marinades, as the acidity in buttermilk helps tenderize meat.

How to Make Buttermilk at Home

If you find yourself ready to bake a recipe that calls for buttermilk and your refrigerator is sans a quart of it, don’t fret. Although store-bought buttermilk is hands down thicker and tangier than homemade, there’s a quick and simple solution if you’re caught in a pinch. Adding lemon juice or vinegar to whole milk curdles it by introducing acid and aiding in the rise and tenderness of baked goods. This method is called clabbering, which just means to curdle and thicken milk or cream. And all it takes is a few minutes.

How to make 1 cup buttermilk:

  1. Add 1 tablespoon fresh lemon juice or cider vinegar (or distilled white vinegar) into a liquid measuring cup.
  2. Add enough whole milk to measure 1 cup and stir.
  3. Set aside until milk is slightly curdled and thickened, 5 to 10 minutes.

How To Store Buttermilk

You will be surprised how long buttermilk can last in the refrigerator. The reason refrigerated buttermilk lasts for so long is that the lactic acid produced through fermentation inhibits the growth of unwanted and dangerous bacteria. This allows for buttermilk to last for three to four weeks in the fridge, and is why it’s often safe to use for a couple of weeks past the sell-by date. Always give buttermilk a good shake before you use it, as the milk solids often tend to settle.

For signs of buttermilk gone bad, look for a grainy texture and an off-putting smell. Regardless of buttermilk generally lasting for a while, it does continue to ferment as it sits, and therefore its desirable taste does change slightly, producing less flavorful outcomes.

Leftover buttermilk can also be frozen in ice cube trays for ease of use. It is important to note that while it preserves its flavor, it does compromise the texture. Still, it’s a great way to prevent waste if there are no pancakes or baked goods in your future. The ice cubes can be thrown into a smoothie for a tang similar to yogurt.

Buttermilk Substitutions

Aside from clabbered milk via the addition of lemon juice or vinegar, there are other substitutes for buttermilk. If a recipe calls for one cup buttermilk, simply add one cup plain yogurt (not Greek) instead. Using plain yogurt as a substitute for buttermilk is especially great for marinades, as the clabbered milk option is not as likely to yield the wanted outcome for a buttermilk-based marinade.

Sour cream is another great option to use as a substitute for buttermilk. Thin it out with some milk or water to reach a similar consistency to buttermilk, and use the same amount called for in the recipe. Aim for about ¾ cup sour cream to ¼ cup milk or water.

Cream of tartar is an acid that can produce similar light and fluffy results in baked goods recipes that call for buttermilk. It’s best to whisk it into the dry ingredients and then mix the milk separately with the wet ingredients, as the powder can clump when mixed right into the milk. For each cup of milk, use 1½ teaspoons cream of tartar.

And while powdered buttermilk can’t be turned into liquid, it can be used in place of liquid buttermilk in baking. It’s widely available at grocery stores, and because it is shelf-stable, it lasts for years. Follow the package instructions for the exact proportions your recipe will need, but essentially the powder is added to the dry ingredients, and water is added to the wet ingredients. For one cup buttermilk, it’s about four tablespoons powdered buttermilk to one cup water.