One day around 1907, the Japanese chemist Kikunae Ikeda was eating a bowl of dashi, the simple kelp-and-fish broth that underlies so much of Japanese cooking, and found himself puzzled by a question that generations of diners had never thought to ask. The broth had a deep, satisfying savouriness that was clearly a taste in its own right, yet it was none of the four tastes his science recognised — not sweet, not sour, not salty, not bitter. Ikeda, a professor at Tokyo Imperial University, set out to find what was producing it. His answer would add a fifth basic taste to the human vocabulary and launch a global industry, and it would take the Western scientific establishment the better part of a century to accept that he had been right all along.
Ikeda's broth
Ikeda focused on kombu, the dried kelp that Japanese cooks steep to make dashi, and set about isolating the chemical responsible for its savoury depth. In 1908 he succeeded: the source was glutamate, an amino acid, present in the kelp as glutamic acid. He named the taste it produced umami, a Japanese word suggesting savouriness or deliciousness, and he argued that it was a distinct basic taste on a par with the established four. The tongue, he proposed, was responding to glutamate directly.
Ikeda was not content to leave his discovery in the laboratory. Recognising its commercial potential, he worked out how to manufacture the savoury compound as a stable seasoning — monosodium glutamate, or MSG, the sodium salt of glutamic acid — that could be sprinkled into any dish to deepen its flavour. He patented the process, and a seasoning was born and marketed under the brand Ajinomoto, meaning "essence of taste," which remains a major company to this day. Glutamate, it turned out, is not exotic at all: it occurs naturally and abundantly in foods the world already loved for their savoury richness — ripe tomatoes, aged Parmesan cheese, mushrooms, cured meats, soy sauce and, indeed, human breast milk. Ikeda had simply identified and bottled the essence of savouriness.
A century of Western doubt
For decades the West was reluctant to grant umami the status Ikeda claimed. The four-taste model was deeply entrenched in textbooks, and there was scepticism that "savoury" was a genuine basic taste rather than a combination of the others or a matter of texture and aroma. Umami remained largely a Japanese concept, respected in Asian food science but marginal elsewhere.
Vindication finally came from biology. Around the turn of the twenty-first century, researchers identified specific taste receptors on the tongue that respond to glutamate — a receptor complex now generally described as T1R1 and T1R3 — providing the physiological proof that umami is detected by dedicated machinery, just as sweetness and bitterness are. With a receptor identified, the case was effectively closed: umami is now widely accepted as the fifth basic taste, and Ikeda's insight, nearly a century old, was confirmed by the tools of modern molecular biology.
The MSG scare
If umami had a public-relations problem in the West, its manufactured form had a far worse one. In 1968 a letter published in a prominent American medical journal described a cluster of symptoms — numbness, palpitations, headache — that the writer associated with eating at Chinese restaurants, and speculated that MSG might be the cause. The phrase "Chinese Restaurant Syndrome" entered the language, and a lasting fear of MSG took hold. For decades the seasoning was treated as a suspect additive; "No MSG" became a selling point, and diners blamed it for all manner of vague after-dinner complaints.
The scientific case against MSG, however, never held up. Rigorous, controlled studies repeatedly failed to find that MSG causes the reactions attributed to it in ordinary dietary amounts, and food-safety authorities have consistently judged it safe. The panic is now widely regarded as one of the more striking examples of a food scare built on weak evidence and, some historians argue, coloured by cultural prejudice against Asian cuisine — for the very same glutamate that made MSG suspect was present, unremarked, in the Parmesan and tomatoes and cured ham that Western cooking prized. The savoury depth people feared in a Chinese takeaway was the identical compound they loved in a bowl of pasta.
Ikeda's legacy, then, is double. He gave the world a new word for a taste it had always experienced but never named, and he gave it a seasoning that concentrates that taste — a seasoning maligned for a generation on grounds that would not survive scrutiny. The fifth taste is now uncontroversial, printed in the textbooks that once ignored it, and the humble amino acid at its heart is recognised as the shared secret of savoury food everywhere. It simply took the world a hundred years to taste what a chemist noticed in a bowl of broth.
Quiz nuggets
- Umami was identified in 1908 by Japanese chemist Kikunae Ikeda, who traced the savoury taste of kombu (kelp) broth to glutamate.
- He named the taste "umami" and manufactured the seasoning monosodium glutamate (MSG), sold under the brand Ajinomoto.
- Glutamate occurs naturally in tomatoes, Parmesan cheese, mushrooms, soy sauce and breast milk.
- Umami was confirmed as the fifth basic taste around 2000, when glutamate taste receptors (T1R1/T1R3) were identified.
- "Chinese Restaurant Syndrome," coined in a 1968 medical-journal letter, fuelled an MSG scare that later studies failed to support.