Umami is the fifth basic taste, alongside sweet, sour, salty, and bitter. It is the savory, brothy quality people notice in foods rich in the amino acid glutamate and related nucleotides such as inosinate and guanylate—think kombu broth, aged cheese, tomatoes, mushrooms, and soy sauce.
Japanese chemist Kikunae Ikeda identified glutamate in kombu dashi in 1908 and named the taste umami. Unlike salty or sour notes that fade quickly, umami tends to spread across the tongue and linger, and combining glutamate-rich ingredients with nucleotide-rich ones can intensify the savoriness through umami synergy.