Buttermilk is available in almost every dairy case in every supermarket, but it remains tragically unappreciated. Too sour for use on cereal or in your morning coffee, buttermilk can take your baked goods from "good" to "great" or from "great" to "extraordinary," adding not just flavor but improving texture and color. Take full advantage of this dairy ingredient after learning a few things about it.
The first and most obvious effect of baking with buttermilk is the taste of the final baked good. Buttermilk, like yogurt, results from the careful fermentation of milk with lactic-acid-producing bacteria. This gives buttermilk its tangy flavor, which adds complexity and depth to the finished baked good. A classic ingredient in buttermilk biscuits, buttermilk is a good choice for use in mild baked goods such yellow cake and sugar cookies.
Baking soda is an alkaline that, when it comes into contact with an acidic ingredient, produces carbon dioxide and lightens the dough. Food scientist Harold McGee, in "On Food and Cooking: The Science and Lore of the Kitchen" reports that unless all the baking soda is consumed by the reaction during baking, it often makes cakes or cookies taste bitter or soapy. Replacing half the milk in a recipe with buttermilk ensures that all the soda will get used without adding too much tang. Don't try this trick for recipes that call for baking powder, as it already contains the necessary acids.
Buttermilk can help you avoid overcooking your baked goods. McGee reports baked goods brown more readily in an alkaline environment. By changing the PH of your baked goods by using buttermilk, you can help keep yellow cakes, sugar cookies and other baked goods from browning too quickly. However, if your oven is especially prone to overbaking or burning, use an oven thermometer, as even high-end ovens loose accuracy over time.
Tips and Considerations
Store all fresh buttermilk in the fridge. Although the acid in buttermilk slows microbial growth, buttermilk will still go bad if not kept cold. If you don't use buttermilk often enough to justify buying fresh buttermilk, "Cook's Illustrated" magazine recommends using buttermilk mix, which works just as well as fresh buttermilk. Also, ask your guests about food allergies before serving food made with buttermilk, as all milk products can be a food allergen.