Buttermilk has two main functions in recipes. One is to provide an acid to react with baking soda. The other is to provide flavor. Although buttermilk got its name for being the liquid left over from butter making, today, buttermilk is milk that has been cultured with bacteria, which produce the lactic acid which makes buttermilk sour, and cause the milk to take on a thick texture. It is difficult to use a buttermilk substitute which will give the exact flavor and texture of buttermilk in a recipe, but it is fairly easy to duplicate the acid effect.
Milk and Lemon Juice or Vinegar Buttermilk Substitute
The buttermilk substitute most often given is a simple mixture of milk with an acid, either lemon juice or vinegar. Here is the formula for one cup:
- 1 tablespoon lemon juice or vinegar to enough whole milk to make one cup total (scant cup of milk)
Put the lemon juice or vinegar into a liquid measuring cup and fill with milk to the one cup mark. Let the mixture sit for five to ten minutes, allowing it to thicken. This substitute will replace the acidity of buttermilk in recipes like buttermilk pancakes or biscuits, but the flavor and texture will not be the same. This substitute is only useful for baking. When buttermilk is used “raw” as in a buttermilk dressing, this will not do!
Milk and Cream of Tartar
Cream of tartar, otherwise known as Potassium bitartrate, potassium hydrogen tartrate, or tartaric acid, is a byproduct of winemaking. It has many uses in cooking, including providing and acid for leavening baked goods. It is used, for example, to activate baking soda in homemade baking powder.
Cream of tartar can be mixed with milk to make a buttermilk substitute. Here is the formula for one cup:
- 1 3/4 teaspoons cream of tartar to one cup of whole milk.
Mix the cream of tartar with the milk and allow to stand for five minutes.
Like the lemon juice or vinegar substitute above, this will duplicate the acid of buttermilk, but not the taste. Since, in baking recipes, the cream of tartar is there to activate the baking soda, baking powder, whether homemade or store-bought could be used. The advantage of mixing the cream of tartar with milk to make a buttermilk substitute is that you will not have to figure out how much baking powder to use, just use your buttermilk stand-in in the amount called for in the recipe, and keep the amount of baking soda the same. However, generally, 1/2 teaspoon of baking soda is used per one cup of buttermilk. The baking soda can be omitted and 2 teaspoons of baking powder can be used, with the same amount of plain milk. This will not allow the milk to clabber, of course, so a better final result may be had by mixing the cream of tartar into the milk, per above formula.
As above, this substitute is only useful to replace buttermilk in baked items or pancakes.
Yogurt Substitute for Buttermilk
Buttermilk can be thought of as similar to watery yogurt. Therefore, plain yogurt makes a fine substitute for buttermilk, much better than any of the substitutes above. The reason it is not listed first is because most folks are more likely to have lemon juice or vinegar on hand, and most bakers have some cream of tartar on hand.
Sometimes, yogurt is used as a direct replacement for buttermilk. However, since yogurt is thicker than buttermilk, it is usually best to thin it down with milk. Use the following formula for one cup:
- 3/4 cup of whole or low-fat plain yogurt to 1/4 cup milk.
Since buttermilk is usually made with nonfat milk, many advise substituting only nonfat or low-fat yogurt mixed with skim or low-fat milk. It is questionable whether this is necessary for most recipes in which you are likely to want a buttermilk substitute. Use what you have on hand.
Can You Substitute Sour Milk for Buttermilk?
The first two buttermilk substitutions are ways to make artificial “sour milk.” Of course, if you keep milk long enough, it will go sour on its own. Can you use milk that has gone sour as a buttermilk substitute? Well, before milk was pasteurized, you generally could. However, today’s milk tends to spoil rather than just sour. In other words, it will have an unpleasant flavor, not just a sour flavor like buttermilk. So, no, do not use spoiled milk as a buttermilk substitute.