Wrinkly Chinese fermented black beans look as though they have just emerged from an archaeological site. Indeed, the salty, pungent little bits are an ancient Chinese staple. Made of black or yellow soybeans, they were once the only soy-based seasoning used all over China but nowadays are mostly employed in southern Chinese cooking.
Called dou chi in Mandarin and dul see in Cantonese, you may know them as the punchy dark flecks in the sparerib nuggets at dim sum. But fermented black beans are remarkably versatile. The beans can star as the gutsy seasoning responsible for the signature flavor of such favorites as clams with black bean sauce. But they don’t mind playing a supporting role too. When braised with meat, they recede into the background to lend an alluring earthiness to the sauce. Use them in vegetarian dishes to imbue ingredients such as tofu with umami depth. Or add them to chile oil to establish a savory backbone.
I keep a supply tucked into my refrigerator door, where it seems to last indefinitely. (Prepared black bean sauces taste monochromatic, so I don’t use them.) When first using the beans, they can seem tricky. Accidentally put too many into the wok and their saltiness prevails, throwing off the flavor balance. One remedy, says acclaimed cookbook author Grace Young (“Stir-Frying to the Sky’s Edge”), is to rinse and mash them first. “Otherwise the flavor is too intense,” she explains.
Some cooks don’t rinse the beans, and I lean toward that camp, achieving balance by reducing the salt or soy sauce in my recipes instead. Whether to mash, chop or keep the beans intact depends on how you want them to play with other ingredients. Render them into small bits to disperse their flavor throughout. Or allow whole beans to plump up during cooking to inject sparks of flavor into every mouthful.
Another useful application is using them in vegetarian stock, as Fuchsia Dunlop suggests in “Revolutionary Chinese Cookbook.” The beans’ umami is released into the brew, which has a porcini-like fragrance.
Look for fermented black beans at Chinese and Southeast Asian markets, usually in the dried, pickled and preserved vegetables aisle. Plastic packages of the beans are fine so long as the beans look bright and fresh, not mashed and old. Use just the beans and discard other bits, such as ginger, that may come in the package.