The most popular steamer used for "baozi" is made out of bamboo ,In the old days, wooden steamer was used only in imperial palace because  wood has a special flavor, but the civil rarely used;Reason 1 is the replacement of wooden steamer is high frequency. Regardless of any short wood fibers as the characteristics of wood are particularly afraid of heat and flooding. Wood at high temperature and long-term immersion in water will rot quickly. Reason 2 was soaked wooden steamer is too heavy - it's hard to lift it by a commom person

Even the bamboo steamer also decay very rapidly, this is not a big deal for a family because they don't use ut very often ,but for restaurant,they have to make replacement every half a year. So now the restaurant industry are using aluminum steamer.