Introduction
Given the ingenuity of Chinese cooks, it should come as no surprise that there is an amazing variety of Chinese soups. However, there are two major categories. Thin soups are made with a clear broth, and cooked quickly, with the meat and/or vegetables added near the final stages of cooking, depending on their individual cooking times. Just as in the case of dashi, the Japanese clear broth, it is important never to overcook the broth for Chinese thin soups. On the other hand, you don't want to overcook the vegetables: the idea is to cook them just enough so that they will still preserve their distinctive flavor.
By contrast, the ingredients for thick soups are all added together at once. The soup is cooked more slowly, giving the ingredients time to blend together. Cornstarch or tapioca starch is often added near the end of the cooking process as a thickener.
Hot and Sour Soup is an example of a thick soup. A number of ingredients such as shredded pork and dried Chinese mushrooms (in northern China it is traditionally made with fresh chicken's blood) are simmered together to form a thick broth, perfect for those cold Mongolian winter nights. Another example is Shark's Fin Soup. Recipes for the famous banquet dish call for it to be made with a thick or "gourmet" stock (see below). Meanwhile, in Ken Hom's Chinese Cookery, the author points out that Chicken and Spinach soup is an excellent example of a thin soup. The vegetable (in this case, spinach) is blanched first, reducing the amount of time it will need to be cooked in the soup. Similarly, the chicken is also blanched ahead of time.
As with French cuisine, the secret of a good Chinese soup lies in the stock. What is stock? Basically, it's a liquid broth in which meat, bones, and sometimes vegetables have been simmered over a long period of time, imparting their flavor to the heated broth. Chicken is the meat of choice for preparing Chinese stock, although pork is also used, particularly in addition to chicken. (Beef is thought to add too strong a flavor). The Chinese place such importance on their stock that they have two categories. A primary or first class chicken stock is made by simmering a whole chicken, while a second class stock uses only the bones. There is also gourmet stock, a truly superior broth made with chicken, pork ribs and other pork bones, ham, and sometimes duck. It is used to create banquet dishes such as Shark's Fin soup.
Besides not using beef, Chinese stock also differs from French stock (known as fonds de cuisine) in the lack of spices. While a recipe for French chicken stock might call for a pinch of tyme or a few garlic cloves, the Chinese believe spicing masks the flavor of the chicken or pork. Seasonings are added later, depending on what the individual recipe calls for.
Thick or thin coup, Which Soup Should I serve?
There's no hard and fast rules, but the following guidelines can help you decide whether a thin or thick soup is called for:
1. Serve a thin soup as a beverage replacement
Contrary to popular belief, the Chinese don't normally drink tea during a meal. Tea is enjoyed afterward in a relaxing atmosphere. Besides encouraging conversation, it helps promote digestion. Water or soft drinks aren't served, as the Chinese believe it is unhealthy to serve cold drinks with a meal. A thin soup makes an appetizing substitute.
2. Serve a thick soup for lunch or dinner
Thick soups make a great one-dish meal, particularly for lunch. Many are quite filling, nearly crossing the line from soup to stew. Thick soups may be served at dinner; as noted above, Shark's Fin Soup is a popular banquet dish, and Hot and Sour Soup goes well with Mu Shu Pork. However, normally you wouldn't serve a thick soup at a meal that has several other dishes.
3. During a banquet, serve a thin soup between courses.
Similar to a sorbet, thin soups can cleanse the palate and prepare it for the next course.