Retronasal olfaction

Retronasal olfaction refers to the perception of aromas by an internal route, when volatile compounds rise from the mouth to the nasal cavity through the pharynx during tasting. It complements direct nasal examination and reveals nuances sometimes absent on inhalation. Often confused with taste, it in fact accounts for most of the flavour perceived, which explains the sensory dulling experienced when the nose is blocked by a cold.