Shanghainese love doujiang (soy milk/soy milk soup) at breakfast. There's a sweet version which is served either hot or cold. The cold version is ubiquitous in its grab-and-go transparent plastic cups; you usually have the hot version at sit-down places, but it's still just plain soy milk with some sugar added. Who likes that? (Well, a lot of people, apparently.)
The savory version is something else; properly done, it's a masterpiece and food for the gods, IMHO. It's hot soy milk to which has been added vinegar or some other sour matter to curdle it (surprisingly, soybean milk curdles much like cow's milk) and salt and/or a salty agent (the best versions will have brine shrimp in it). Chili oil is usually also present, so with the salty, sour, and spicy combination you'd need only have to add a little sugar to make "Strange Taste Doujiang" but I don't think I would like that. Beyond the above ingredients, other vegetable matter such as scallion tops may be added, and it's sometimes served with a bit of Nori-type seaweed on top. The other indispensable ingredient is slices or broken pieces of you tiao, the Chinese cruller, floating on top. (It's a good thing the do with stale you tiao.)
When I'm in Shanghai I crave savory doujiang for breakfast, and my wife's experience and intuition is`usually successful at tracking down a good version. On my last trip , however, I did a lot of early morning foraging by myeslf, and found it difficult to communicate that I wanted savory doujiang. My attempted Mandarin or Shanghainese request usually resulted in shrugged shoulders or in my getting sweet doujiang (yuck!)
Finally I asked my wife for help. "Simple," she said. "Just ask for 'A-jiang'" (with an "A" as if speaking the name of the English letter "A"). The next time out I found it worked like a charm. My wife then pointed out that if you order "B-jiang" in Shanghai you'll get plain soy milk, and if you ask for "D-jiang" you'll get the sweet version. There apparently is no "C-jiang", not even a "Gentleman's C-jiang" but apart from that I approve of this grading system; I'd give a good version of savory doujiang an "A" any day, and a sweet version a "D" (if not an "F").
Gary Soup is a blogger, tweeter and sometimes poster to foodie web sites, usually blathering about Chinese food. He is a retired transport planner with an abiding interest in all aspects of Asian and other ethnic foods and their place in the world. He has twice been married to Shanghainese women who happened to be good cooks and consequently is well-grounded in Shanghainese "jia chang" cuisine. He is based in San Francisco, but spends as much time as he can in Shanghai and New York and can sometimes be seen prowling the streets of Montreal. He is the author of two articles on food in the guidebook "Urbanatomy: Shanghai" and has been a guest blogger for the Asian Art Museum on the food of Shanghai. He currently maintains two Blogger blogs, and posts a lot to flickr. Some earlier online efforts of Mr. Soup drift about the World Wide Web as cyberspace junk.