What is the proper way to make a herbal decoction?

 What is the proper way to make a herbal decoction?

Just like cooking, it is important to follow the proper steps. Incorrect preparation may impact on the intended effects. 

A ceramic clay or crockery pot with a lid works best; however, an enamel or glass pot can also be used. Iron, aluminium and copper pots should be avoided because chemical interaction can occur and affect the original nature of the ingredients.

Uncontaminated cool water is best. Physicians may recommend using rice wine or a combination of water and wine for certain types of decoctions. 

Add water until the herbs are lightly submerged; soak for 20-30 minutes so the effective contents can be easily extracted when boiled. Bring to a boil quickly and then turn the heat down as required for the time given. 

The specific time and heat used in preparing your decoction are determined by the properties and nature of the ingredients. Generally, cold and flu or purgative decoctions are boiled on high heat for 20-30 minutes. Tonic or other decoctions that contain rich sticky substances are decocted for a longer time (approximately one hour) with mild heat and more water. In order to achieve the best results, your physician should clarify what type of decoction you are preparing, the appropriate amount of water that should be used and how long it should be boiled.

The herbal compounds and the liquids are commonly boiled down to one glass or 250ml. Then it should be filtered into a container while straining the dregs. If the decocted herbal ingredients are overheated or burnt, the whole decoction should be discarded because damaged ingredients can produce undesirable effects.

Certain ingredients must be treated differently due to their special properties. If they are in your prescription, the ingredients are usually packed separately. For example, shells and minerals have to be smashed and decocted first; volatile and aromatic substances like peppermint and Amomum fruits are added near the end and are cooked for 5 minutes only. Substances like Biond Magnolia flower and Plantain seed must be wrapped in gauze, because they make the decoction turbid or irritate the throat. Expensive substances such as deer horn and ginseng are sliced and boiled separately, so that their active ingredients are not affected by other herbs. Their decoctions can either be taken together with other decoctions or drunk separately. Some colloid ingredients like honey or malt sugar should be melted into the warm finished decoction directly. Some rare aromatic substances like musk are ground into powder and taken with a decoction or lukewarm water. 

If preparing your own decoction seems like a daunting task, many herbal shops and physicians can provide this service when asked.