[Decoction by Pharmacy vs. Decoction by Oneself]
Decoction by pharmacy preserves the efficacy of volatile components
Hospitals use automatic decoction machines for decoction, which is conducted in a closed and high-pressure environment. The parameters such as time and pressure are set, and after decoction, the liquid is squeezed manually or automatically and transported to the automatic packaging machine for packaging.
Some commonly used Chinese herbs, such as peppermint, turmeric, and acorus tatarinowii, contain volatile oil components, which are the effective ingredients of the herbs. During decoction, it is necessary to minimize the loss of these components to ensure the efficacy of the herbs. The fully sealed automatic decoction machine can maximize the prevention of the escape of volatile oil components.
On the contrary, when decocting by oneself, the effective ingredients are exposed to the air when the liquid boils, and the high temperature decoction may cause some components to oxidize, resulting in a decrease in concentration rather than an increase.
Traditional decoction allows flexibility in adding herbs
Throughout history, traditional medical experts have summarized a set of decoction methods through long-term practice to fully exert the therapeutic effects of herbs.
Special requirements for decoction: Some prescriptions require certain herbs to be decocted first (such as turtle shell and daizheshi), and some herbs to be added later (such as rhubarb and sandalwood), while some herbs need to be decocted separately (such as ginseng). With self-decoction, the time for adding herbs can be adjusted according to the needs, which cannot be achieved with pharmacy decoction.
[Further Reading: Basic Knowledge of Decoction of Chinese Herbs]
Before Decoction
Cleaning: Generally, there is no need to clean before decoction. If there is sediment in the herbs, it can be quickly rinsed with water, avoiding soaking to prevent the loss of some water-soluble components.
Soaking: Soak the herbs in cold water for about half an hour before decoction, which can dissolve the water-soluble components in the herbal soup and increase the concentration of the decoction.
During Decoction
Water: The water level should be about 2-3cm above the surface of the herbs, or gently press the herbs with your hand, and the water level should just cover the back of your hand. Usually, some flower and herb herbs have a large water absorption, and the water level will decrease after soaking for half an hour. In this case, add cold water to the standard water level before starting decoction.
Heat: Generally, medium heat should be used for decoction, and switch to low heat after boiling. However, for some herbs used to treat external conditions, they can be decocted with medium heat for about 15 minutes after boiling.
Time: For most Chinese herbs, the first decoction should be 20-25 minutes, and the second decoction should be 15-20 minutes. For herbs used to treat external conditions, the first decoction should be 10-15 minutes, and the second decoction should be 10 minutes. For herbs used for nourishing, the first decoction should be 30-40 minutes, and the second decoction should be 25-30 minutes.
Double Decoction: After two decoctions, the effective ingredients of the herbs are greatly reduced, so it is best to decoct twice. However, for herbs used for nourishing, three decoctions can be performed. For some prescriptions with a large dosage, three decoctions can also be performed.
After Decoction
Immediate Filtration: After decoction, the herbal soup should be filtered and poured out while hot, and should not be left in the pot for a long time. Otherwise, the herbal liquid with excessive colloids will gel as the temperature decreases, making it difficult to filter and affecting the efficacy, while also causing acid spoilage.
Decoction Container
Earthen pots and clay pots are the best choices. Enamel and stainless steel pots are also acceptable, but avoid using aluminum, iron, and copper pots to prevent reactions between the metal utensils and the herbs, which may affect the efficacy of the herbs and even harm the human body.
[Warm Tip: Pay Attention to "Decoction First, Then Add"]
The purpose of "decoction first" is usually to increase the solubility of certain drugs or reduce their toxicity, while "adding later" is to reduce the loss of volatile oil and prevent the degradation of effective ingredients.
Mineral drugs such as shells and animal horns, which are hard in texture, must be decocted first to extract their effective ingredients. For example, gypsum, cassia seed, turtle shell, and soft-shelled turtle shell should be crushed and decocted for 30 minutes before adding other herbs for decoction. Some toxic herbs, such as Aconitum, Fuzi, and Shanglu, must be decocted for 1-2 hours to achieve detoxification. In addition, some herbal medicines such as Curcuma, Cannabis seed, and Dendrobium need to be decocted for 10-30 minutes before exerting their effects.
Herbs that are added later include herbs with a fragrant smell and high content of volatile oil, such as peppermint, patchouli, cardamom, as well as herbs that should not be decocted for a long time, such as hook vine and apricot kernel. These herbs should be added to the pot 5-10 minutes before the decoction of the soup.
