Think back to elementary school health class. Aside from learning about good-touch/bad-touch and basic hygiene, you probably learned about the Five Senses. (sight, hearing, touch, smell and the pertinent sense for today ... taste)
Taste -- broken down since the times of Ancient Greece into salty, sweet, bitter and sour. Accepted for literally thousands of years, those four simple tastes combine with aromas into every flavor we've ever tasted.
There's a Fifth Taste.
In the late 1800s Chef Auguste Escoffier invented veal stock. It took over 24 hours to properly prepare and set the cuisine world on its ear with its amazing taste. A taste that was not salty, sour, sweet or bitter. So how could we be tasting it?
At roughly the same time on the other side of the planet, Kikunae Ikeda (a chemist, incidentally) loved him some soup. Specifically, dashi, a basic seaweed soup used in a bunch of dishes (much the same way a French chef might use veal stock as a basis of everything else on the menu). Being a chemist, Ikeda went to his lab for the answers and discovered glutamic acid, which he named "Umami." Or "Yummy."
Yup, the Fifth Taste is "yummy."
And, it turns out it's legit (well, its existence, anyway, the name is another issue). We have glutamate receptors on our tongues. These help with tasting meats, cheeses, tomatoes, mushrooms, beans, Worcestershire sauce, olives (the salt is added), wine (now we know why the sommeliers have such trouble describing the wines they're sampling ... they're not sweet, bitter, sour or salty. Not truly any of those.), vinegar, corn (in its grain form).
So, next time you think something is delicious in a non-salty, non-sweet, non-bitter, non-sour kind of way. Well, the word you're looking for is "yummy."
ps. Heard this all on NPR yesterday and found it fascinating (obviously, or I wouldn't be blogging it).