Is sour milk the same as buttermilk? I have half a quart of gooey milk to do something with.
New York, New York
When a recipe calls for “buttermilk,” it is usually referring to the buttermilk sold in supermarkets, which is a processed food made from low-fat milk. (True buttermilk is the liquid portion that remains after cream is churned into butter. It’s not usually sold in stores.)
If your gooey milk tastes tangy but pleasant, then you can probably use it in recipes that call for buttermilk or sour milk (some recipes call for adding an acid — usually lemon or vinegar — to make sour milk). If your sour milk tastes or smells unpleasant to you, then you should simply toss it. Sometimes “good” bacteria will have inoculated the milk and the result will be a tangy, yogurtlike flavor. Other times, bacteria that produce unpleasant flavors will have gotten the upper hand, and when this happens, it’s too late to salvage your milk. If you decide the milk in your refrigerator smells OK and is all right to keep, one traditional thing to do with (slightly) sour milk is make pudding. You can also use sour milk in cream sauces — you could try making enchiladas in a creamy, cheesy sauce, or bake a chicken breast or fish fillet with milk and herbs poured over it.
To learn more fascinating things about milk, I highly recommend the book Milk: The Surprising Story of Milk Through the Ages by Anne Mendelson.
— Tabitha Alterman, food editor