Decoction means a process, or action, of extracting the essence of something from something. Decoction is a concentrated liquor resulting from heating or boiling a substance, especially a medicinal preparation made from a part of a plant. Decoction method is used for extraction: boiling a plant material such as a root, bark, stem or rhizome to dissolve the chemicals of the material, and then boiling in water to extract oils, organic compounds and other chemical substances. Decoction is used to make tisanes, tinctures and similar solutions for treatment.
Decoction is derived from the Latin word decoquere (meaning to boil down): de ‘from’ and coquere ‘to cook’; and the word dates back to mid-fourteenth century.
Decoction is applied in herbalism to extract fluids from the hard parts of a plant. Kashayam is a type of herbal medicine, in Ayurveda uses decoction method.
To extract coffee from coffee powder, decoction method is used with the aid of a coffee filter such as in making South Indian filter coffee. The coffee filter comes with an upper cylinder whose bottom has minute holes to let the brew drip into lower cylinder usually made of stainless steel. The filter also comes with disc for tamping the coffee powder when placed in the upper cylinder. The thick liquid collected in the lower cylinder is the decoction. The decoction is used in making South Indian filter coffee by adding to it milk and sugar to taste. This mixture is poured back and forth in quick successions, between a dabarah (saucer, cup with a lip) and tumbler to a drinkable temperature and till froth (a mass of small bubbles on the surface of the liquid) forms.
Nowadays there are readymade decoctions sold in the market for those who do not have time to make the decoction but want to have a cup of South Indian filter coffee.