Occasionally, manufacturers of wine glasses try to promote their product by claiming that some particular design is better for wine because it delivers the wine to a different part of the mouth, thereby increasing one sensation (the one whose receptors are concentrated in that part of the the tongue).
You may have even seen a drawing of the tongue with different areas assigned to different taste sensations. Sweetness is on the front tip, bitterness along the sides in the back and so on. It's an interesting thought, it sounds like it could be useful, for anyone trying to amplify the experience of one taste or diminish another. Unfortunately, it's dead wrong.
Before we talk about it any more, it might be worth taking a second right now to touch, let’s say, a bit of salt to the front of your tongue where the sweet receptors are supposed to be. Taste salty? You bet it does. In general, we taste most tastes everywhere on the tongue. The story of how this particular weird idea has been passed down and accepted uncritically is a good cautionary tale.
The tongue map dates back to research by D.P. Hanig that was published in 1901. Hanig set out to measure the relative sensitivity on the tongue for the four known basic tastes that were then known in Europe. Based on his subjects’ reports, he concluded that sensitivity to the four tastes varied around the tongue, with sweet sensations peaking in the tip, etc.
In 1942, Edwin Boring took Hanig's data and graphed the levels of sensitivity. Boring’s graph made it seem like areas of lower sensitivity were areas of no sensitivity. The modern tongue-map was born as an artifact of the way the chart was presented.
In 1974, a scientist named Virginia Collings re-examined Hanig's work and agreed with his main point: There was some difference in sensitivity to the four basic tastes in different parts of the tongue, but the variations were too small to matter. Collings found that all five tastes (she included umami) can be detected on taste buds anywhere: all over the tongue, on the soft palate and in the flap that blocks food from the windpipe.
Later research has revealed that taste bud seems to contain 50 to 100 receptors for each taste. There’s still some uncertainty about the distribution of taste receptors, but the map itself is a pure myth.
In fact, there are enough stories like The Tongue Map that they have their own category: they're called fakelore. You may have heard that you can tenderize meat my marinating it or that browning ‘seals in juices’. Maybe you’ve put a spoon in a bottle of Champagne to conserve the sparkle. Or perhaps you believe the one about spices originally being used to conceal the taste of rotten meat. Beware of folks who want to sound smart by passing along the bull: watch out for the Tongue Mappers! (Oh, and try to be aware when you're being one yourself.)
For more on the taste of beer, check out: