It is only in the past decade that the redoubtable ‘map of the tongue’ has begun to fall out of circulation. The diagram, which dates to the early twentieth century and can still be found in some medical textbooks, places the taste buds for sweetness on the tip of the tongue, those for bitterness at the back, the ability to taste salt on the top edges, and sourness on the bottom edges. … In fact, all the regions of the tongue are capable of recognizing sweet, salty, bitter, and sour flavors, as well as savory tastes, which had been left off the original map altogether.
I remember that silly tongue map from the grade school science textbook. I remember thinking it was absurd the second I laid eyes on it. It’s easy enough to test. Point your tongue and touch a bit of salt to it. Do you taste the salt? Bet you do! I recall pointing this out and being given some amazing nonsense about how the molecules of salt flavor must have instantaneously been transported to the edges of my tongue.
The quote above is from The New Yorker, May 12, 2008, D.T. Max’s profile of the chef Grant Achatz.