Flavour is composed principally of the sensations of smell and taste, though the senses of sight, touch, and hearing interact with those of smell and taste. Whereas the sense of taste is relatively simple in having only four modalities—bitter, salt, sour, sweet (with perhaps astringent, soapy, and MSG-like)—the modalities of smell are still very much under discussion; the 44 qualities described by Harper et al.1 are a good summary of the current state of knowledge.