You may not have noticed, but in the mid-1990s you gained an extra taste. We went to bed one night, all happy with our four taste receptors for sweet, sour, salty and bitter, and then, while we were asleep, the tide of thinking in food science changed incontrovertibly. We woke up with another taste, one known well in Asia but not in the West. That day we were able to taste umami, the so-called fifth taste.
Of course, we had the taste receptors to recognise and savour the briny, mouth-filling taste all along; as Japanese chefs had long argued. But it was only then that scientific thought on the matter reached a critical mass. It became, if you like, an umami tsunami.
Before that, when we were making marinades or the more adventurous of us were creating new dishes, we built them – subconsciously or otherwise – around the other four pillars of taste, which with a bit of luck would all be present in there somewhere in a nice, harmonious balance. In short, no one ever shoved a fork into a stew, tried it and said, "hmm, needs a little more umami". Perhaps most of us, chefs and home cooks alike, do still think in that four-point paradigm. But for a growing number, ignoring umami would be like missing out on bread or potatoes.
For starters, witness the wealth of restaurants making hay with the taste. In London there's Umami, the East Asian restaurant that opened last month in Kensington, which makes great play with the flavour in its noodle and broth dishes. The Hawksmoor, too, goes big on it. Routinely referred to as the best burger and steak restaurant in town, it serves a Longhorn beef burger that has been specially constructed, not just with the fifth taste in mind – but around it. But as its executive chef Richard Turner points out: "We build our entire menu on it; not many other chefs are even aware of it."
Likewise, when Heston Blumenthal started redesigning British Airways' in-flight menu he increased the amount of umami in the food, having found that while other tastes recede in the arid atmosphere of the cabin, umami does not. He has also spoken of its centrality to his cooking at his Michelin-starred Fat Duck restaurant in Bray. It is, he has said, "something very close to my heart". At this point you might find yourself saying: all well and good, but this sounds like something for the culinary élite, something on the edges of the avant garde. But that isn't quite so. In LA, punters snake out of the doors of Adam Fleischman's seven Umami Burger joints, where the extroverted, tightly stacked meat buns costs $10 (£6). (Not quite McDonald's prices, but not bad either.) "Although we only opened in 2009, we sell 5,000 burgers every day," says Fleischman, who has successfully trademarked the name "umami".
Closer to home, the Italian cookery writer Laura Santtini has teamed up with the man behind the Michelin-starred Nobu chain, Nobu Masuhisa, to create a new Taste No 5 Umami Far Eastern Vegetarian paste. The second of her umami pastes (the first was inspired by Mediterranean umami flavours), it goes on sale in Waitrose in April.
Look at that roster of chefs and restaurants and what becomes clear is that umami isn't bound to a geographical area, price bracket or type of food. Richard Turner says the reason is simple: you find umami everywhere. "Deconstruct a Hawksmoor umami burger and you won't find anything particularly out of the ordinary," he says. According to Turner, they add fried mushroom, sun-dried tomato, roasted parmesan and ogleshield cheese, slow-fried onions, ketchup and some Parmesan butter to the Longhorn beef patty. "It has been hit and miss for customers," Turner says. "But if you are open to it, it gives a flavour that is the essence of savouriness."
Ah yes, that elusive flavour. What is it that gives it what is described in the US as "mouthfulness", by Laura Santtini as "pure deliciousness" and – not altogether helpfully – by the journal Chemical Science as the "flavour of boiled crab"? Jeya Henry, professor of human nutrition at Oxford Brookes University, says: "A food that is high in umami is rich in an amino acid called glutamate, one of the building blocks of protein. In high concentrations it makes food very flavoursome. There have been an awful lot of studies to support this. After all, it has been around as a concept in the West for quite some time."
In fact, it dates back to 1907. It was then that the chemistry professor Kikunae Ikeda, of Tokyo Imperial University, noted a taste "common to asparagus, tomatoes, cheese and meat, but which is not one of the four well-known tastes". It was he who first isolated the glutamate (and gave it its name, which is a play on the word umai, which loosely translates as yum in Japanese). What he also did, which may account for some residual cynicism, is use this know-how to manufacture it. He invented MSG (monosodium glutamate), which subsequently became a leitmotif for unhealthy, takeaway-style eating in the late 20th century, an all-purpose bogeyman. The charges laid against MSG have included, variously, that it induces headaches, allergies and causes dehydration (together referred to as Chinese Restaurant Syndrome). And in the foodies' hive mind, Umami and MSG were indelibly linked. If then, MSG is a pure expression of umami, in the same way sugar is the classic expression of sweet, should we go easy on it? Is the 200,000 tonnes of MSG made each year actually a danger to our collective health? Should we avoid umami-rich food?
Not at all, Professor Henry says. "First of all, we should note, Chinese Restaurant Syndrome has been shown to be something of an old wives' tale," he says. "Numerous big clinical studies have debunked it. You have to understand glutamates have always been with us and part of our diets; you even find them in breast milk. It would be a great pity if anyone missed out on the umami taste because of these residual claims. They're the equivalent of saying the earth is flat: it isn't, and glutamates won't harm you."
Umami, then, has come of age – and things are looking just rosy for it. Where once it was seen as a blight, now it skips around that part of the health spectrum marked "blessing". The reason? It is a handy alternative to salt. Just as a few pinches of sodium can improve a dish, so the well judged addition of a few anchovies or a lump of parmesan can pump up the umami without detracting from the flavour. By playing with the fifth taste we can reduce artery-hardening fat and salt in dishes, without losing out on the flavour.
It is that rare, almost unique thing: something that tastes good and won't make you fat, ill, intoxicated or soporific. So, we may have been too busy listening to Blur or voting New Labour to notice this addition to our palate in the 1990s, but today, with its ascent, there's little excuse not to make hay with this very interesting taste.