5 basic flavour types are now counted: salty, sweet, sour, bitter and umami. Umami is the flavor that characterizes soy sauce and is thought to be due to sodium glutamate.

"Taste" can be defined as the sensation of substances which activate various combinations of the sensory cells of taste that occur mainly on the tongue and to some extent in the pharynx and on the epiglottis.

The activity gives rise to nerve impulses. These are led by the seventh, by the ninth and to a small extent by the tenth cranial nerve into the medulla oblongata. Here, the signals are switched on in the solitarius nucleus for further spread to higher levels in the brain.

The ninth cranial nerve - the glossopharyngeus nerve - is considered the most important taste nerve.