Should I use hot or cold water to soak Chinese medicine?

Many people are accustomed to soaking Chinese medicinal materials in boiling water before decocting them, thinking that this will not only reduce the decocting time, but also allow the ingredients of the Chinese medicinal materials to be mixed as much as possible. In fact, this is a misunderstanding that lacks scientific research. Chinese medicinal materials cannot be soaked in boiling water. The protein contained in Chinese medicinal materials will coagulate due to the sudden heat when it comes into contact with boiling water, and will harden the plant cells and form an inseparable cell membrane on the surface, preventing the essential ingredients from being fully mixed. The high-molecular-weight materials contained in Chinese medicinal materials tend to produce colloidal solutions when in contact with boiling water, which is also not conducive to the extravasation of components. When Chinese medicinal materials are cleaned and crushed, the powder left on the surface will melt due to sudden heat, blocking the capillary channels of Chinese medicinal materials, making it impossible for water to penetrate, and the ingredients cannot diffuse out after melting, which finally affects the decoction of the ingredients. Aromatic Chinese medicinal materials, such as mint, perilla leaves, costusroot, white cardamom, nutmeg, etc., contain volatile oils and volatile substances, which are easily evaporated when heated. They are not suitable for soaking in boiling water, and they should be boiled later.

There are two common problems when boiling Chinese medicine

1. The medicine tank must be cleaned

When decocting Chinese medicinal materials, the medicinal juice is extracted due to the evaporation of water, and a layer of medicinal scale often accumulates at the bottom and around the medicine pot. If the medicines in the medicine pot are often changed and the accumulated medicine scale is not wiped off in time, when new medicines are added for decoction, the medicine scale will dissolve, affecting and reducing the efficacy of the medicine, and even missing the disease. Especially if you have previously prepared medicines with obvious toxic side effects or external medicines that cannot be passed through the mouth, poisoning may occur. In addition, if the Chinese medicine is not cleaned immediately after each decoction, the scale at the bottom of the medicine pot will become thicker and thicker, which will easily burn when the Chinese medicine is decocted again, thus losing its medicinal effect.

2. Fry thoroughly and absorb dry

"Decoction thoroughly" means to allow the ingredients of the medicine to be fully released, which is the basic requirement for decocting Chinese medicine. Medicines with a firm color and which cannot release their ingredients immediately can only be decocted separately, decocted first, or decocted for a long time to make the medicinal juice thick and fully exert its medicinal power. Medicines with loose color and light and fragrant effects do not need to be decocted for too long; but herbs with light weight and large body should be mixed frequently to facilitate decocting the medicine thoroughly.

Generally speaking, Chinese medicinal materials should be soaked in cold water for about 30 minutes before decocting; however, experiments have shown that the optimum temperature for soaking Chinese medicinal materials before decocting is 40℃～50℃. This condition can make the Chinese medicinal materials moist and fully swollen, and increase the decoction rate of the ingredients.