The story of umami begins at about the same time Escoffier invented tournedos Rossini, a filet mignon served with foie gras and sauced with a reduced veal stock and a scattering of black truffles. The year was 1907, and the Japanese chemist Kikunae Ikeda, as curious about the tongue from a scientific perspective as was Escoffier from an artistic one, had asked himself a simple question: What does dashi taste like?

Dashi is a classic Japanese broth made from kombu, a dried form of kelp. Since at least A.D. 797, it has been used in Japanese cooking the same way Escoffier used stock: as a universal solvent, a base for every dish. But to Ikeda, the dashi his wife cooked every night didn’t taste like any of the four classic tastes or even like some unique combination of them. It was simply delicious. Or, as the Japanese would say, it was umami.

So Ikeda began his quixotic quest for this unknown taste. He distilled fields of seaweed, searching for the essence that might trigger the same mysterious sensation as a steaming bowl of seaweed broth. He also explored other cuisines. “There is a taste,” Ikeda declared, “which is common to asparagus, tomatoes, cheese and meat but which is not one of the four well-known tastes.” Finally, after patient years of lonely chemistry, during which he tried to distill the secret ingredient that dashi and veal stock had in common, Ikeda found his secret molecule. It was glutamic acid, the precursor of L-glutamate. He announced his discovery in the Journal of the Chemical Society of Tokyo.

Glutamic acid is tasteless. Only when the protein is broken down by cooking, fermentation or ripening in the sun does it degenerate into L-glutamate, which the tongue can taste. “This study has discovered two facts,” Ikeda wrote in his conclusion. “One is that the broth of seaweed contains glutamate and the other that glutamate causes the taste sensation ‘umami.’”
Ikeda’s research, though a seminal finding in the physiology of taste, was completely ignored. Science thought it had the tongue solved. Ever since Democritus hypothesized in the fourth century B.C. that the sensation of taste was an effect of the shape of food particles, the tongue has been seen as a simple muscle. Sweet things, according to Democritus, were “round and large in their atoms,” while “the astringently sour is that which is large in its atoms but rough, angular and not spherical.” Saltiness was caused by isosceles atoms, while bitterness was “spherical, smooth, scalene and small.” Plato believed Democritus, and wrote in Timaeus that differences in taste were caused by atoms on the tongue entering the small veins that traveled to the heart. Aristotle, in turn, believed Plato. In De Anima, the four primary tastes Aristotle described were the already classic sweet, sour, salty and bitter.