Retronasal smell
How aroma released while chewing travels up the back of the throat to the nose and makes up most of flavour.
Also: flavour perception, smell from the mouth, taste and smell
Retronasal smell is the route by which aroma molecules released in the mouth pass behind the palate to the nose. It is distinct from orthonasal smell, which comes through the nostrils when sniffing. Most of what we call taste is in fact retronasal smell, which explains why food seems bland with a blocked nose. Spices excel here: warm foods release more volatile oils, and chewing breaks up seeds and releases more. Exhaling through the nose after a mouthful of curry intensifies the aroma. Cooks use the effect with finishing spices that give a burst after the first bite.