Peking-style hoisin sauce ingredients include starches such as sweet potato, wheat or rice, and water, sugar, soybeans, sesame seeds, white distilled vinegar, salt, garlic, red chili peppers, and sometimes preservatives or coloring agents. Traditionally, hoisin sauce is made using toasted mashed soy beans. Despite the literal meaning, hoisin sauce does not contain seafood, nor is it typically used with it. Neither does it contain plums, even though it is frequently misidentified as plum sauce.
In Vietnamese, hoisin sauce is called "tương đen". It is a popular condiment for phở, a Vietnamese noodle soup; the sauce can be directly added into a bowl of phở at the table, or can be used as a side dip for the meat of phở dishes. In phở, hoisin is typically accompanied by Sriracha sauce or "tương đỏ". The hoisin sauce is also used to make dipping sauce for Vietnamese spring rolls (American)/summer rolls (British) and other dishes similar to spring/summer rolls. In cooking, it can be used for glazing broiled chicken.