A decoction is similar to an infusion except that the plant material is brought to a boil in the water and simmered for 15 minutes before straining. Decoctions can be used with harder parts of the plant such as bark, roots, or nuts. Compared to an extraction, more chemical components will be extracted but the chemicals that evaporate the most rapidly (the most volatile) may evaporate due to the increased heat. For example malted barley grain can be ground, added to water and then heated for hours to release sugars from the grain. In herbal medicine compounds in roots can be extracted by mashing and extended boiling.

from the Latin de + coquere which means “of/from” + “to cook”.