"Before items like soy sauce, oyster sauce, etc. were commercially produced on a large scale, where did people get them?" asks luckyfatima. "Did they make them at home? Were there special home-businesses or shops which made these sauces in-house as a specialty, and people would go to these small businesses to purchase them? If the latter is the case, are these sauces still available in this way, and the mass produced bottles only more popular with Chinese diasporic communities? Or do people in China also use mass produced bottled products?"
"As far as I know, most condiment type sauces were usually made by professionals," says jumpingmonk. "Much as European villages often had people who worked as bakers, cheesemakers and sausage makers, Asian towns would often have people or families who specialized in making things like soy sauce, oyster sauce etc. This actually makes sense. Soy sauce is usually designed to be made in very large amounts, by the barrelful (well, enormous jar but the idea is more or less the same). ... So when you were done each of the jars you made would be something on the order of 40-50 gallons. Even for a condiment used as regularly as soy sauce, it would be hard for a single family to use up that much soy sauce before most of it began to spoil or go off. ... So most towns relied on a professional to make it and bought from them."
"Having watched my paternal grandmother make her own dwehnjang (Korean soy bean paste) and gochoojahng (Korean chili paste), I'm inclined to think people did make the stuff at home," says inaplasticcup. "I know that some Vietnamese and Thai people still make their own fish sauce and a lot of the stuff that's sold to the locals is made in someone's home. (Granted, they're not nearly regulated as we are, for good and for bad ...) So I would imagine there are lots of people in China, especially in rural areas, who buy these condiments from cottage operations."
Discuss: Chinese cooking sauces in the past