ATK
Can yogurt or milk be substituted for buttermilk?
While we try to keep a carton of buttermilk in the back of the refrigerator—it keeps for ages—there are those days when we run out and really need it for a batch of pancakes or biscuits. Can yogurt or milk serve as a suitable substitute?
Yogurt
To find out if there is a simple conversion for replacing buttermilk with yogurt, we went into the test kitchen and cooked up our recipes for Tall and Fluffy Buttermilk Biscuits, Best Buttermilk Waffles, and Buttermilk Mashed Potatoes.
At first we tried simply substituting equal amounts of plain whole-milk yogurt for buttermilk. The resulting biscuits and waffles were a bit dense and dry, and the mashed potatoes were somewhat stiff. To improve the texture, we next thinned the yogurt with milk, using 3 parts yogurt to 1 part milk. While the yogurt-based biscuits and waffles were slightly less tangy than the buttermilk versions, tasters found that thinned yogurt (whole-milk or low-fat) was a perfectly acceptable substitution. (Avoid nonfat yogurt; it produced biscuits and waffles that were too dry.)
The mashed potatoes were a different story. While their consistency remained the same with yogurt, the lack of the buttermilk’s tang was noticeable in this savory dish. Our advice? For baked goods, a mixture of 3 parts plain whole-milk or low-fat yogurt to 1 part milk can be swapped for buttermilk (that translates to 3/4 cup yogurt plus 1/4 cup milk to replace 1 cup buttermilk). For savory recipes, stick with the real thing.
Milk
Regular milk can be "clabbered" with an acidic ingredient such as lemon juice, vinegar, or cream of tartar; the acid will react with baking soda to produce leavening and will approximate the tang of buttermilk in most pancake batters and baked goods. For 1 cup of milk, simply add 1 tablespoon of lemon juice, white vinegar, or cream of tartar and let the milk stand for about 10 minutes. This milk will be similar to buttermilk in sourness and acid content, but it will not be as thick.
Note: Lemon juice is our first choice; some sensitive tasters detected off flavors from vinegar and cream of tartar.