This classic French white sauce is traditionally made with whole milk. Could we lighten up béchamel while still maintaining its rich flavor and consistency?
A béchamel is a basic French white sauce made by stirring milk into a butter-flour roux. It is the base for numerous dishes such as lasagna and creamed spinach. To find out whether skim milk can be substituted for whole milk in a béchamel without sacrificing flavor, we cooked up both kinds using 4 tablespoons butter, ¼ cup flour, 4 cups milk, and ¾ teaspoon salt. Tasted on its own, the skim version lacked the rich flavor of the sauce made with whole milk and was noticeably less viscous. Flavor differences faded away once we tasted the sauces baked in spinach lasagna and lasagna Bolognese, but the skim milk sauce’s thinness was still evident. To add body, we experimented with increasing the amounts of both butter and flour. Ultimately, we found that just an extra teaspoon of flour per cup of milk was enough to turn this lighter sauce into a perfectly acceptable substitute for whole-milk béchamel when cooked into recipes.