Before boiling
Cleaning: Generally, there is no need to clean before boiling. If there is mud or sediment in the herbs, you can quickly rinse them with water, but avoid soaking them to prevent loss of water-soluble components.
Soaking: Soak the herbs in cold water for about half an hour before boiling. This can extract water-soluble components into the soup and increase the concentration of the herbal soup.
During boiling
Water: It is ideal to have the water cover the herbs by about 2-3cm or lightly press down the herbs with your hand so that the water just covers the back of your hand. Generally, herbs such as flowers and plants absorb more water, so after soaking for half an hour, the water level may decrease. In this case, you can add more cold water to reach the standard water level before starting the boiling process.
Heat: Generally, Chinese herbs should be boiled with strong heat first and then simmered with gentle heat. However, for some herbs used to treat external conditions, you can continue to boil them with strong heat for about 15 minutes after boiling.
Time: For most Chinese herbs, the first boiling should take about 20-25 minutes, and the second boiling should take 15-20 minutes. For herbs used to relieve external conditions, the first boiling should take 10-15 minutes and the second boiling should take 10 minutes. For nourishing herbs, the first boiling should take 30-40 minutes and the second boiling should take 25-30 minutes.
Double boiling: After boiling the herbs twice, the effective ingredients in the medicinal decoction are greatly reduced, so it is best to boil the herbs twice. However, for nourishing herbs, they can be boiled three times. For some prescriptions with large amounts of herbs, they can also be boiled three times.
After boiling
Immediate filtration: After boiling the medicinal decoction, it should be filtered and poured out while hot, and should not be left in the pot for too long. Otherwise, the medicinal decoction containing excessive colloids may gel with the decrease in temperature, making it difficult to filter and affecting the efficacy of the herbs. It can also easily lead to sour spoilage.
Boiling equipment
Earthen pots and sand pots are the best. The best boiling equipment is traditional earthen pots or sand pots. Enamel and stainless steel pots can also be used, but avoid using aluminum, iron, and copper pots to prevent reactions between metal utensils and herbs, which can affect the efficacy of the herbs and even be harmful to human health.
Reminder: Pay attention to "first boiling, then adding"
The purpose of "first boiling" is usually to increase the solubility of certain herbs or reduce the toxicity of the herbs. "Adding later" is to reduce the loss of volatile oils and avoid the destruction of active ingredients.
Generally, minerals such as shells and animal horns, which have a hard texture, must be boiled first to help extract their active ingredients. For example, gypsum, abelmoschus, turtle shell, and turtle plastron can be crushed and boiled for 30 minutes before adding other herbs for boiling. Some toxic herbs, such as aconite, fuzi, and rhizoma homalomenae, must be boiled for 1-2 hours before they can achieve detoxification. In addition, some plant herbs, such as gardenia, hemp seed, and dendrobium, also need to be boiled for 10-30 minutes to exert their effects.
The herbs to be added later include herbs with a strong fragrance and a high content of volatile oils, such as peppermint, patchouli, cardamom, and sand ginger. Some herbs that should not be boiled for too long, such as hook vine and almond, should be added to the pot 5-10 minutes before the decoction is finished.
