Steaming is cooking by steam.
Steaming is a preferred cooking method of health conscious individuals because no cooking oil is needed, resulting in a lower fat content. Steaming also results in a more nutritious food than boiling because fewer nutrients are destroyed or leeched away into the water.
In western cooking, steaming is usually used to cook vegetables, and only rarely to cook meats. On the contrary, vegatables are seldom steamed in Chinese cooking, vegetables are mostly stir fried or blanched instead. In Chinese cooking, steaming is used to cook many meat dishes, for example, steamed whole fish, steamed pork spare ribs, steamed pork or beef cake, steamed chicken, steamed goose etc. Other than meat dishes, many Chinese rice and wheat food are steamed too. Examples include buns, Chinese steamed cakes etc. Steamed meat dishes (except some dim sum) are less common in Chinese restaurant than in traditional home cooking because meats usually require longer cooking time to steam than stir frying.
The Chinese chefs developed an efficient method of restaurant cooking. Big bamboo steaming baskets each three feet in diameter, four inches tall can be stacked up on top of a wok like a chimney. The bottom of each basket is a grid which allows the steam from the wok to rise all the way to the top of the stack. In kitchen of some dim sum restaurants, a steaming stack can be 20 levels high. The bottom level is removed when done and the entire stack simply shift downward. This technique ensures a constant supply of freshly steamed dim sum.
Steaming at home can be done with a wok. A shelf is put on the bottom of the wok. A small steam basket or a dish of food is put on the shelf. Water is filled to just below the dish or basket. Keep the water boiling with a lid on. Most vegetable dishes are done in just five minutes. Most meat dishes take over 20 minutes.
Another common alternative is to put the dish on top of the rice being cooked. A pot of rice takes about 30 minutes to cook. The dish is ready when the rice is.
Specialized steamers are available in the market. They are more convenient but not necessarily better.