L-Glutamate and the Dimensions of Taste

How many tastes can a human being taste?

The answer used to be four -- until a French chef named Auguste Escoffier came along during the late 19th century. Soon, researchers decided there was a taste that didn't fall into the previous four categories of sweet, salty, bitter and sour. According to NPR:

. . . (Escoffier) created meals that tasted like no combination of salty, sour, sweet and bitter; they tasted new. Escoffier invented veal stock.

. . . halfway across the world, a chemist named Kikunae Ikeda was at the very same time enjoying a bowl of dashi, a classic Japanese soup made from seaweed. He too sensed that he was tasting something beyond category. Dashi has been used by Japanese cooks much the way Escoffier used stock, as a base for all kinds of foods. And it was, thought Ikeda, simply delicious.

But what was it? Being a chemist, Ikeda could find out. He knew what he was tasting was, as he wrote, "common to asparagus, tomatoes, cheese and meat but … not one of the four well-known tastes."

Ikeda went into his lab and found the secret ingredient. He wrote in a journal for the Chemical Society of Tokyo that it was glutamic acid, but he decided to rename it. He called it "umami," which means "delicious" or "yummy" in Japanese.

You can hear the full audio of the story that aired this morning on NPR.