Why are people used to cooking Chinese medicine in casserole instead of other pots?

Pots such as casseroles or pottery have slow heat transfer, uniform heat conduction, moderate heat, strong thermal insulation around the pot, difficult chemical changes and low price. Other pots may cause chemical changes. As we all know, casserole, pottery, pottery, enamel, stainless steel pot and heat-resistant glassware are the best decoctions. But it is not suitable to use iron pot, copper pot, aluminum pot and other decoctions. Why?

First of all, containers such as casseroles or pottery have slow heat transfer, uniform heat conduction, moderate heat, strong heat preservation around the pot, difficult chemical changes and low price. Decocting with slow fire takes a long time, so the water in the pot is not easy to evaporate, and the effective components in the medicine can be well dissolved.

Secondly, some Chinese medicines, such as Radix Rehmanniae, Radix Scrophulariae, Galla Chinensis, Sanguisorba officinalis and Radix Paeoniae Alba, all contain tannic acid, which is an astringent and easily soluble in water. It is a medicine with good astringent effect. Therefore, tannic acid is often used as "antidiarrheal drug" or "hemostatic drug". However, once tannic acid meets metals with enhanced chemical activity, such as iron, copper, aluminum, etc., it is easy to form water-insoluble films, that is, precipitation of iron tannic acid and copper tannic acid. As a result, tannic acid changed from water-soluble component to no longer soluble in water and could not be absorbed by human body.

In addition, Chinese medicine usually contains alkaloids. Traditional Chinese medicine can treat diseases because these alkaloids play various special physiological roles. For example, ephedrine can treat bronchitis; Rauvolpine can treat hypertension and so on. These indispensable alkaloids have a remarkable feature. Most of them are insoluble in water. Only when it reacts with organic acids such as tannic acid to form salts can it be dissolved by water. If decocted in a metal pan, the loss of tannic acid is too great, which will affect the dissolution of alkaloids and thus affect the curative effect of traditional Chinese medicine. Finally, metal cans are easy to form some water-insoluble precipitates with other compounds in traditional Chinese medicine. The composition of casserole is silicate, and its chemical properties are very inactive, thus effectively eliminating some problems existing in metal pots and giving full play to the role of traditional Chinese medicine.