One of the first things many of us learned in science class was that the tongue is organized like a factory floor plan, with each region assigned responsibility for its own highly specialized tasks:
If you spent your childhood shotgunning Pixy Stix like the rest of us, you may have noticed that you could taste sugar even when it was bypassing the tip of your tongue at 70 mph. You were left to conclude that your teachers were liars or that there was something hideously wrong with you, depending on whether you were raised Catholic.
Your teachers were probably just being fed the same line of bullshit that's been passed from biology class to biology class for decades, and it' totally false. As with the myth that spinach is rich in iron, this one started with a mistranslation of a century-old German study (maybe stop relying on those, science). In 1901, German scientist D.P. Hanig conducted a taste test and found that some volunteers experienced certain flavors more intensely in certain regions of the tongue. Forty years later, a Harvard academic appropriately named Dr. Boring mistranslated the results of the German survey, mistaking a vague tendency among a bunch of Germans (who were probably taste-testing four different varieties of sauerkraut) for the precision workflow chart you see in the tongue map.
Researchers have known for years that all areas in the tongue are about equally good at detecting different flavors. It's not an evenly distributed democracy of taste buds, but every tongue has different patterns of strength and weakness . Your tongue map is like your mouth's fingerprint, if the pattern on your fingerprint determines whether or not you like Brussels sprouts. Each of our "tongue maps" will detect different tastes, sometimes from the same meal. Also, far from being relegated to specific locations on the tongue, your taste buds go all the way down your throat into your digestive system. When you've eaten some bad food, the ones in your stomach warn your gag reflex that if it doesn't evacuate the building, the shit's about to hit the fan (and everything else within three square blocks).
The tastemap has hung around 30 years after it was officially debunked even though it's less interesting than the reality because teachers need cool-looking color-coded maps to fill out science books, and fat-cat wineglass makers like to pretend you need a golf bag's worth of specialized wineglasses to direct different types of wine to the best possible place on the tongue.