Hoisin sauce is the intensely flavored, dark-brown Chinese dipping sauce that perks up classics like Peking duck and mu-shu pork. Hoisin is made from fermented soybeans, sugar, garlic, chiles, and vinegar, and its high sugar content makes it a wonderful addition to barbecue sauces and marinades for roasted or grilled meats. It also brings tangy, robust flavor to stir-fried greens such as bok choy, broccoli, or spinach.
Supermarket hoisin sauces vary widely in flavor, color, and consistency, the best being dark brown, thick, and richly flavored with soy, garlic, and chiles. A good hoisin sauce should have a nice balance of sweet and salty notes and lots of soy flavor.
Hoisin sauce will keep indefinitely refrigerated in a non-metal container. If you buy canned hoisin, transfer it to a nonmetal container, tightly seal it and store it in the refrigerator.