The Sixth Taste

Food​ is money. Or it can be, if you know how to transform it into profit. Ajinomoto Co. is Japan’s biggest producer of condiments and seasonings, with annual revenues of ¥1 trillion, or around $9 billion. Its most successful product by far – on shelves across East Asia since 1908 – is Aji-No-Moto, often sold in a little glass bottle with a trademark red label. I’ve never tried the stuff, but it’s meant to be a short cut to deliciousness: sprinkle a pinch of the crystalline powder into a soup or sauce and it instantly imparts a magical boost of that moreish, meaty, savoury taste we now know as umami.

Aji-No-Moto has a lovely founding legend. In 1899 Kikunae Ikeda of Tokyo’s Imperial University took leave from his post as professor of chemistry to study in Leipzig, where the best researchers could be found. He found other things in Germany too. They included cheese, tomatoes, asparagus and meat. For 1200 years meat had been banned in Japan – and, try as he might, the Meiji emperor found it hard to shift the habits of a millennium. But, abroad: what a strange new world of flavours! Ikeda was sure he had detected something that couldn’t be accounted for in the accepted taxonomy of four fundamental tastes – sweet, sour, salty, bitter. In time, he went back home, where his wife made him a meal with a traditional dashi broth – and there it was again, that same ineffable taste he had encountered in Leipzig. Being the fine chemist he was, Ikeda set out to analyse the ingredient the broth was made from, konbu, an edible variety of kelp. After boiling down the liquid, Ikeda was left with small brown crystals which – eureka! – had the taste he remembered from Germany and recognised in his wife’s marvellous soup.

The crystals were a form of glutamic acid, and the soluble salt Ikeda eventually derived from it to deliver the taste he called umami (‘deliciousness’) was, of course, monosodium glutamate. And so, with the help of the Suzuki Pharmaceutical Company, he went to market. In an article for Gastronomica magazine in 2005, Jordan Sand related the trials Ajinomoto Co. faced in getting people to buy its red-label product. At first they tried to persuade commercial enterprises – soy sauce breweries, kamaboko fish cake businesses – to bulk-buy the powder for its savoury boost. But uptake was negligible, and it was met with scorn by Japanese chefs proudly defending their time-honoured artisanal skills. So over the following years the company settled on a different target market by advertising to Japanese housewives aspiring to sophisticated, Westernised culinary excellence in a bourgeois domestic setting. By the 1920s, when vials of Aji-No-Moto seasoning adorned shelves and dining tables in urban households across Japan, the company was supplying a sample bottle and cookbook to every new graduate of the burgeoning higher schools for women. Dashi made from seaweed or dried fish was for grandmothers: the modern home cook believed in efficiency and innovation.

It was time for the bottled miracle to take on the world. After expansion into Japan’s colonial possessions – noodle shops and street vendors in Taiwan, food dealerships in Korea – it infiltrated China by concocting a Chinese name for itself to disguise its origin as a vector of Japanese imperialism. After the Second World War Ajinomoto Co. established footholds in Europe and North America, though in the US it immediately faced home-grown competition from an identical flavouring cooked up by the International Minerals & Chemical Corporation of Chicago, unleashed under the slogan ‘Ac’cent® makes food flavours sing.’

By now Ajinomoto Co. had perfected the means of production. The original method had involved shovelling wheat flour into heated earthenware vats and pouring in hydrochloric acid to break down the wheat proteins and leave crystallised glutamate. In the 1950s a novel technique was discovered: it turned out that certain bacteria, when cultured in a mixture of carbohydrates and ammonia, generate large amounts of glutamate and excrete it as waste. If you think this sounds unappetising, there’s no need to worry. Glutamate is one of the twenty naturally occurring amino acids used by almost all living things. In humans it’s classified as ‘non-essential’, which means not that we don’t need it but that it doesn’t have to be acquired from food: it’s so abundant and central to the body’s systems that we synthesise it ourselves. It’s involved in vital processes of metabolism and acts as our primary excitatory neurotransmitter, its headline benefit being the role it plays in cognitive functions such as learning and memory.

And glutamate or glutamic acid is ubiquitous, making up a third of the protein in wheat and existing in every type of grain we consume, from rice to corn to barley. The savoury taste we experience, though, comes from the free form of the amino acid that isn’t bound up in proteins. Some plants are naturally very rich in free glutamate – seaweeds, tomatoes, peas – and provide a hint of Ikeda’s umami richness without any human help. Fungi and fish are full of them too, as are pork and beef. But the flavour is intensified by techniques we’ve used for as long as we can remember, such as curing, drying and fermentation, which free more glutamate from its protein bindings. In almost every region of the world some version of one of these methods has been handed down: in Russia it’s salted herring, in Poland smoked sausage. There’s the shrimp paste of the Philippines, the fish sauce of Thailand, the cured alpaca of Peru, the mouldy shark of Iceland. Britain’s greatest creations along these lines are Worcestershire sauce, Marmite and Bovril. Try not to be embarrassed.

What Ikeda didn’t know was that it isn’t only glutamate that generates the taste he found so appealing: two other natural acids, inosinate and guanylate, work to elicit it too, and – for a reason that isn’t yet understood – the taste is considerably magnified when glutamate is combined with one of them or the other. People unconsciously realised this long before any recipe was written down. In addition to the konbu, Japanese dashi is often made with either dried shiitake mushrooms or katsuobushi, the dried flakes of bonito or skipjack tuna. The reason they perform the magic they do when simmered along with kelp is that the shiitake is rich in guanylate and the fish flakes are full of inosinate. A perfect flavour bomb.

The extreme simplicity of the Japanese method of preparation means that there’s no distraction from a taste of pure umami. A French bouillon has the taste too, but because of its many other flavours the umami is hard to detect unless the stock is simmered for a very long time – give it a week? Dashi, by contrast, needs no more than twenty minutes on the stove. But simple and effective combinations can be found in many familiar places. Take Italian cooking. Tomatoes and balsamic vinegar, anchovies and garlic, or mushrooms and Parmesan (the umamiest cheese on Earth). Experiments show that even infants prefer umami-inducing ingredients in combination to any one of them in isolation: plain avocado is likely to be rejected, but add balsamic vinegar and sesame oil and it’s wolfed down in an instant. (I should admit that I’ve conducted this experiment only on a sample size of one.)

Ikeda’s genius was to condense all this knowledge – acquired by trial and error over centuries, or millennia – and to bottle it up. But for Ajinomoto Co. the success couldn’t last. In 1968 the New England Journal of Medicine published a letter from Robert Ho Man Kwok of the US National Biomedical Research Foundation. ‘For several years since I have been in this country,’ he wrote, ‘I have experienced a strange syndrome whenever I have eaten out in a Chinese restaurant.’ Fifteen minutes or so after finishing a meal he would experience a range of unpleasant symptoms: ‘numbness in the back of the neck, gradually radiating to both arms and the back, general weakness, and palpitation’. Kwok narrowed down the cause to the MSG so popular in the Chinese eateries now spreading across America. The journal began referring to the effect as Chinese Restaurant Syndrome, and reports from sufferers abounded. The following year John Olney of Washington University set out to confirm these findings under laboratory conditions. His experiment involved injecting newborn mice with monosodium glutamate, and the results were alarming: the effects on the mice culminated in acute neural necrosis – aka brain damage. A few biochemists questioned Olney’s methodology and conclusions: unlike his mice, people tended to eat glutamate rather than inject themselves with it; human infants, unlike infant mice, have an effective blood-brain barrier that prevents ingested glutamate from reaching the brain; and the doses Olney applied were big enough to floor a horse. But amid the roar of noise about the dangers of eating Chinese food these dissenting voices were barely heard.

Then Ralph Nader took up the charge, lobbying Congress and the Food and Drug Administration to ban MSG, particularly from baby food. The FDA resisted and monosodium glutamate remained on its safe list, but campaigners argued this only proved it was in hock to the MSG industry. People started avoiding Chinese restaurants and food manufacturers removed it from their products. For Ajinomoto Co. it was financially devastating. Revenue from Western countries plummeted and even in Japan MSG consumption fell by a quarter. Double-blind trials showing that Chinese Restaurant Syndrome had no medical basis – that sufferers experienced the same headaches and palpitations whether they had been given MSG or a placebo – did nothing to alter the general belief that Chinese food was bad for you. In the 1990s I got the headaches too. Viral hysteria had taken hold, and MSG’s reputation still hasn’t fully recovered.

Every virus has to start somewhere, but the source of this one remained a mystery for fifty years. In 2017 Jennifer LeMesurier, a professor of writing and rhetoric, published an article examining the language used in old issues of the NEJM. She wanted, among other things, to show how racist tropes about Chinese Americans pervaded the correspondence provoked by Dr Ho Man Kwok’s letter, to which a large number of medical professionals had responded with horror stories of their own. Then, in January 2018, LeMesurier listened to a voicemail message left on her phone. ‘Boy, have I got a surprise for you,’ the voice said. ‘I am Dr Ho Man Kwok.’ He turned out, in fact, to be Howard Steel, a retired orthopaedic surgeon. Steel was now 96, and he had a story to tell.

In 1968 he had been working at a hospital in Philadelphia when a colleague bet him $10 that he couldn’t make it into the pages of the NEJM. After a night of too much food and too many beers at his favourite local Chinese restaurant, he had the fun idea of sending in a joke letter, making it as ridiculous as possible by claiming an affiliation with a fictitious institution, the National Biomedical Research Foundation, and signing off with a name that was very clearly meant to be read as ‘Human Crock’. The journal’s editors didn’t spot the joke – but its readers did, and the letters that followed outdid one another in silliness, including one from a doctor who reported that after consuming ‘24 ounces of beer’ he and his companions had a Chinese meal which led to appalling symptoms: ‘a tightening of my masseter and temporalis muscles, lacrimation, periorbital fasciculation, numbness of the neck and hands, palpitation, and syncope’. Oh, how they must have lacrimated! Doctors are hilarious.

If only the executives of Ajinomoto Co. had known about the hoax they might have been saved from a rocky five decades. Since they didn’t, they had to come up with new ways of persuading people that they were selling something both healthful and unique. And that meant selling a concept. In 1985 an organisation calling itself the Society for Research on Umami Taste organised a symposium in Hawaii at which the various delegates – including a contingent of biochemists from Ajinomoto Co. – agreed that umami should be considered the fifth basic taste. Over the next few years Ajinomoto scientists published several papers on the taste receptors involved in detecting glutamate, with the result that by the early 2000s umami’s status could be said to be proven. This was vindication, nearly a century on, for Ikeda’s big idea. The term monosodium glutamate, with its chemical taint, could be sidelined now that umami had taken hold. A word which had never circulated much beyond the walls of conference venues soon filtered into the popular press, and top-notch cookbooks began bursting with ideas for umami-rich dishes. MSG itself couldn’t have been less fashionable, but the umami boom was a great blessing for a company founded on the essence of that taste.

Ajinomoto Co. rode the wave. Any marketing campaign worth its salt recognises the value of celebrity endorsement, so Ajinomoto set out to woo the crème de la crème. Heston Blumenthal was particularly smitten. In 2004 he was invited to a temple in Kyoto to learn about umami, and returned to create Sound of the Sea, a celebration of umami and the shorelines of Japan, for his menu at the Fat Duck: edible sand made from powdered konbu and miso oil, foamy waves of konbu and wakame stock infused with clams and oyster juice, shellfish dressed in a classical ponzu sauce elevated with the citrus juice of yuzu and sudachi – all enjoyed while listening on an iPod to the cries of seagulls overhead.

Blumenthal has been an informal cultural ambassador for the umami brand ever since. Along with Thomas Keller and Harold McGee, author of On Food and Cooking, he has contributed words and enthusiasm to various publications from the Umami Information Centre, an organisation whose purpose becomes less obscure when you learn that it’s funded by the Umami Manufacturers Association of Japan, which in turn receives funding from Ajinomoto Co., whose global headquarters in Tokyo’s Chūō business district are a five-minute walk from the association’s office. But all this genial activity to spread the word about the general wonders of umami doesn’t address Ajinomoto’s specific problem, which is that everyone still hates its star product, its cash cow, packaged MSG. In 2018 the company spent $10 million on a campaign to win over hearts and minds by sending out a ground-level force of bloggers, YouTubers and social media influencers with the message that MSG might not be so bad. It went about as well as you’d expect. There was at least one small victory: a nice bit of hashtag lobbying persuaded Merriam-Webster to preface its online definition of ‘Chinese Restaurant Syndrome’ with the note: ‘dated, sometimes offensive’.

Publicity can only do so much when everyone is afraid of what you have to sell. The only option is to sell them something new. Ajinomoto Co. had already introduced a new taste to the world – why stop at five? In recent years the term ‘kokumi’ had been popping up in papers by Ajinomoto biochemists. The Japanese language has always had a word, koku, to describe a set of sensations – usually translated as ‘thickness’, ‘mouthfulness’ and ‘lingeringness’ – prompted by richly pleasing foods. (I’m sure Japanese people know exactly what they mean by koku, but thick lingering mouthfulness makes me think I’m eating cotton wool.) The neologism ‘kokumi’ (the -mi suffix means ‘taste’) referred, counterintuitively, to compounds that didn’t themselves taste of anything but which could induce a koku sensation, giving a food more body, while also intensifying other tastes like umami or saltiness. Things only became more confusing in 2010, when Ajinomoto scientists reported in the Journal of Biological Chemistry that our calcium-seeking taste receptors do respond to kokumi substances. This finding is easy to misinterpret, since responding isn’t the same as tasting, but the implication was enough to excite the mainstream press: ‘Move over umami, a sixth taste sensation has been discovered.’

But what Ajinomoto is excited about, now that its kokumi-delivering SavorBoost™ is ready to go, are the tricks its latest invention can perform. Since kokumi doesn’t add any taste of its own, it can be used in places MSG could never go. If you try enhancing the flavour of a biscuit with MSG it may end up tasting of Marmite. But use kokumi to make the biscuit biscuitier and nobody need know that anything was added at all. Perhaps kokumi will put an end to the misery of people who buy low-fat, low-salt food while secretly wishing they were eating the full-fat version that actually has some flavour. It can make something seem salty when it isn’t, or rich and buttery when it’s nearly fat-free. Kokumi: the ‘sixth taste’, a taste that isn’t a taste that creates the illusion of a taste that isn’t there. That’s real alchemical genius: money from nothing at all.

Listen to Daniel Soar discuss this piece on the LRB Podcast.