THEY might sit there, unnoticed and undisturbed, in your fridge or cabinet, for weeks or months or even longer. But they’re waiting — or at least they should be — until your stir-fries need a jolt of distinctive, impossible-to-mistake flavor that nothing else can give you.

They are fermented black beans, and in an Asian market a dollar or two buys a pound, a supply that will last you a long time because you use only a tablespoon or two at a time.

The beans in question are black soybeans, not the black turtle beans used in Latin American cooking. Salting ferments them, turning them soft, bitter, odd-tasting and, in small quantities at least, delicious.

The most common way to use them is in stir-fries, though you can also mince them with garlic and ginger, for example, and rub them on meat you plan to roast or grill, or sprinkle them on fish you plan to steam.

The stir-fry route remains my favorite. Here I take that route with shrimp and bok choy, but as you probably know, the technique can be used with almost any combination of protein and vegetable.

Soak the beans in white wine, sherry or water while you prepare the other ingredients. Stir in the beans and their soaking liquid at the last minute and your dish is pretty much transformed. It’s not unlike shaving truffles onto whatever you’re eating: the dish just becomes more powerful.

And the beans are probably sitting in your fridge already. Or should be.