The fifth taste came out of a broth

For centuries it was taken for granted that the tongue told apart four tastes: sweet, salty, sour and bitter. But in 1908, the Japanese chemist Kikunae Ikeda noticed that his kombu broth, made from a seaweed, had a savoury, rounded flavour that didn't fit any of those four boxes.

Instead of letting it go, he investigated. He analysed the broth until he isolated the culprit: glutamate, an amino acid also found in ripe tomato, aged cheese, meat and soy sauce. He named that flavour umami, which in Japanese roughly means "delicious".

It took almost a century to be fully accepted, until the specific receptors that detect it were found on the tongue. Today umami is officially the fifth basic taste. It all started because someone actually paid attention to their soup.