When decocting Chinese herbs, a suitable pot is essential. So, what kind of pot is best for decocting herbs?
Best Pots for Decoction
Clay pots and earthenware jars are optimal for decoction; glass or enamelware (if intact) are acceptable alternatives. Iron, copper, aluminum, and tin pots should never be used. This is because herbal medicines contain complex chemical compounds. Metals like copper, iron, and aluminum react chemically with these compounds due to their high reactivity.For instance, iron readily reacts with tannins to form iron tannate, darkening the decoction and imparting an iron-rust flavor that compromises efficacy. Aluminum reacts with organic acids to form compounds that accumulate in organs like the liver and kidneys upon absorption, causing harm. Copper utensils oxidize when heated, producing harmful copper patina. All these factors degrade decoction quality and directly impact clinical efficacy.
Additionally, some individuals use household clay pots for decoction. These must be thoroughly cleaned until no oil film appears when rinsed with water, as residual fats can diminish the efficacy of herbal medicines.
Heat Control for Decoction
Medium to low heat is optimal. Bring the decoction to a boil over medium heat, then reduce to low heat. Maintain a gentle simmer where the liquid bubbles slightly but does not overflow. Note: If herbs burn during decoction, discard the mixture entirely; do not add water and resume boiling.
Decoction Duration
Time should be measured from the moment the decoction reaches a rolling boil. For approximately 100 grams of herbs, 15-20 minutes is generally sufficient. For larger quantities, extend the time by 3-5 minutes as needed. For smaller doses, such as pediatric formulas (often around 20 grams), reduce the time; boiling for 2-3 minutes after reaching a rolling boil is typically adequate.Over-decoction makes the taste unpalatable and creates overheated water, where enlarged water molecule clusters reduce permeability to cell walls. Decoction time should be further shortened for formulas primarily composed of flowers or leaves.
Water Volume for Steeping
If tolerable, use slightly more water than the physician's specified bowl measurement. Many find bowl sizes difficult to gauge; simply use approximately 200-250 milliliters per bowl.Adding more water allows the herbs to steep thoroughly, facilitating the release of active compounds. While this results in a larger volume of decoction, it enhances bodily absorption. For approximately 100 grams of herbs, I typically prepare 250-300 milliliters per dose (equivalent to half a bottle of mineral water). For twice-daily dosing, prepare around 600 milliliters; for three times daily, prepare about 900 milliliters.
Alternatively, calculate water volume this way: Herbs absorb twice their weight in water. For example, 100 grams of herbs (excluding stony ones) absorb 200 milliliters of water (1 gram of water equals 1 milliliter). Simmering for 25 minutes evaporates about 150-200 milliliters, leaving the medicinal broth.Therefore, total water added (ml) = Total herb weight (g) × 2 + 150 + 300 × number of doses. Use a mineral water bottle to measure roughly—slight overfilling is acceptable.
Storage of Decoction
Herbal decoctions prepared by pharmacies can be stored sealed in a cool, dry place for extended periods. Preparing a week's worth at once is perfectly fine.