Stir-frying is the most characteristic method of cooking in Chinese. It is a common feature throughout the various regional cooking styles of China. To define stir-frying in one breath would be big-fire-shallow-oil-continual-stirring-quick-frying of cut-up ingredients with wet seasoning. Because of the quickness of the process, stir frying is particularly good for preserving the vitamins of foods, especially of green vegetables, a method that appeals to the health conscious.
Chinese restaurant chefs like to show off their skill in stir fried dishes, and are often judged by them. Done well, stir frying produces meats that are juicy and flavorful, vegetables - crunchy and tender, fresh and 'bursting' in vivid colors; it is undeniably one of the most appetizing ways of Chinese cooking!
Tips : For better flavor, always stir-fry seasoning ingredients such as garlic and ginger before you add other ingredients.
In stir-frying, the food is cooked over high heat in a wok with little oil, just enough to lightly coat all of them. The oil is added when the wok is hot enough and the ingredients only 'go down into the wok' (as Chinese would say it) when the oil is sufficiently heated (smoking from the edges). Because you stir fry at high heat, you must use a cooking oil with a high smoke point, that is, one that will not burn and become smoky at high temperatures. Butter is unsuitable. The best choices are bland-flavored vegetables oils such as peanut, soybean, corn, canola, safflower, and sunflower. To evenly and quickly cook and coat the food with oil, which is essential to seal in as much natural juices in the vegetables or meat as possible, they are spread up the walls of the wok, then toss it together again in the center using a Chinese spatula. This process is repeated throughout the whole cooking. Often, a Chinese chef would lift the wok with one hand (padded of course) from the stove and shake it such that the food toss and turn in the wok. You can try this if you have a strong wrist and arm but be careful or you will end up with food all over the place and not on the dining table.
While the stir-frying itself usually takes but two or three minutes, the preparation of the material often takes a lot of trouble. As stir frying is a very quick process, it just does not allow time to turn around and scramble amid a chaos of half prepared ingredients. So, prepare and cut the right ingredients into small pieces, slices, shreds, or cubes, etc. If different ingredients take different lengths of time to cook, each has to be put in at the right time, so as to come out done together. So separate them in different bowls as in the order they are to be cooked.