People often say that "the steamed bun is not cooked and the gas is not round". The implication is that this kind of steamed bread has become a "dead dough lump", or it is caused by this "gas" (that is, water vapor).
When the steamed bread embryo wakes up, the pot is opened, and the cage cover is covered, with the continuous heating, the heat in the steamer gradually rises, and the water vapor will increase synchronously. When the steam rises to the cage cover which is still in a low temperature state, it will instantly form condensed water, that is, distilled water. At this point, the steamed bread is still green, and the distilled water will drip on it. Because the air pressure is unstable when just steaming, the air flow is large and small, so that the green embryo can not expand. This kind of steamed bread, which is close to the dead embryo, can't change this "sick" shape even if the air pressure rises in the later stage, and it is not impossible for the steamed bread to become a dead dough lump after boiling.
Steamed steamed bread can not be without steam, and steam depends on heating the boiler water to generate enough heat. In this way, you have to use fire all the time to have a lot of water vapor. However, if the firepower is too large, there will be a phenomenon of "excess" of water vapor. Generally speaking, most families or steamed bread shops use aluminum steamer. However, this kind of steamer is relatively closed, and a large amount of "excess" water vapor can not be discharged from the air hole of the steamer cover or the gap of the steamer in time, so it has to hover in the steamer. It is very likely to drip on the surface of individual steamed bread (you might as well cover the top drawer with a clean white cloth).