There are doubtless many things in the world that human beings have long known about but didn't have a name for, and umami is one of them. The fifth (and final?) taste, after sweetness, sourness, bitterness and saltiness, was identified and named only a little over a century ago, and defined as a taste in its own right much more recently. It is often described as meaty or brothy or as having a full or rounded flavour.

But the fact we've known its taste since humans at various points around the ancient world started making cheese or drying anchovies has engendered some resistance to the term, including from the scientific community. Some would point out we've always known what "savoury" meant, and others that umami is used only by the kind of wankers who grab hold of any neologism to stay ahead of the pack.

What all that fails to acknowledge is the wealth of concerted work in the culinary and nutritional fields sparked by a Japanese professor's experiment in 1907 to find out what gave dashi, the rich stock made from kombu (kelp) and bonito flakes, its unique taste. The result is the opportunity for heightened taste experiences for diners and health benefits deriving from umami's nutritional value and palatability, particularly for the very young and the very old.

So whether you've experimented with chef Peter Gilmore's umami dressing of unsalted butter, ground dried konbu and shiitake mushroom, toasted sesame seeds, fish sauce, lemon rind and white miso (Gourmet Traveller, August 2016), or reducing your intake of sodium and beefing up on iodine by substituting table salt with sea seasonings such as sea lettuce flakes, you're taking part in the fifth-taste revolution kicked off by Professor Kikunai Ikeda's musings.

Distinctive taste

Experiments by this chemist from Tokyo University to identify the constituents of dried kombu found its distinctive taste is derived from glutamate, an amino acid that is one of the building blocks of protein. He named it "umami", from the Japanese for "deliciousness", and went on to mimic the flavour in the controversial seasoning MSG (monosodium glutamate), which after late 20th-century claims of severe side effects is now considered safe for consumption in moderate doses.

Some years after his discovery, two of Ikeda's disciples went on to identify further umami compounds: inosinate, found only in animal food products and guanylate, which occurs in foods of plant origin. Where foods with glutamate are combined with these, taste and flavour are intensified.

So maybe our early ancestors knew what they were doing when they threw meat, bones and vegetables into a pot and created broths or stews high in umami. Fish sauces in the ancient world are often cited as an early recognition of umami, given those used by the Romans (garum and liquamen) were very similar in production to the fish sauces of South-East Asia in the same period and used for the same purpose – as a flavour enhancer often in place of salt.

Foods with high levels of umami include tomatoes, cheese (especially aged parmigiano reggiano), shiitake mushrooms, cured ham, anchovies and soy-based and fermented products. Combining umami bombs such as these or the ingredients listed above in Gilmore's umami butter, creates an intense taste sensation that is picked up by multiple receptors coating the whole tongue. As different tastes are more commonly picked up at different points of the tongue, this is thought to give umami the amplitude or fullness often attributed to the taste, and an aftertaste that lingers longer.

Internationally acclaimed Australian chef Dan Hunter of Brae restaurant in regional Victoria uses a lot of different techniques in his kitchen to create the sensation of umami. "For me umami in a very basic sense is probably the purest form of savoury. It's the missing flavour that sits in the middle of your palate, then falls over the side of the tongue and really grips for a long time. It's a thing that cooks in restaurants are always looking for to round out dishes. 

"Traditionally in the west we say things like some dish could have had more sugar or more salt. We use cultural references for what we know. If you are making a beef stew, you may say it needs a bit more salt to make it more savoury but really to make a tasty stew you just have to caramelize the meat and that's how you develop the umami."

One quick umami builder that's gaining converts in among cooks in Western home kitchens is furikake or "rice seasoning", a mixture of ground dried fish, sesame seeds, seaweed, salt, and sugar. In addition to sprinkling it on boiled rice, Japanese cooks use it as a pickling spice. A second seasoning mixture, togarashi, is a sort of chilli pepper blend, the exact composition of which varies from producer to producer. In addition to ground chillies, dried seaweed and orange peel are typical togarashi components.

The fact umami triggers the secretion of saliva and digestive juices helps with the smooth digestion of protein – a nutrient crucial in the development of the human species; it is one of the building blocks of human tissue and also provides fuel for the body. Glutamate is vital to metabolism and brain function as a neurotransmitter and maybe our responsiveness to the taste all begins with mother's milk, which is also rich in glutamate.

Changing structure

The way we handle food of course also changes its structure. Ageing, ripening, curing and fermenting all increase levels of umami. And while these processes were crucial for the preservation of food and in aiding digestion from pre-historic times onwards, the fact they were also providing palatability is significant.

Since the confirmation of multiple taste receptors specific to umami in 2009, and its designation as a distinct taste, research into glutamate has exploded; it is now one of the most intensely studied ingredients in the food supply.

Much of the interest is centred on its nutritional potential, its capacity to rebuild lost appetite, and its use in salt-reduced diets. A 2010 article in Food Insight, the journal of the International Food Information Council, noted work being done "to clarify relationships between savoury taste perception, MSG, body weight, appetite regulation and eating behaviour".

In summary, the journal wrote: "Few molecules of biological importance appear to have as many roles as glutamate does in the body. From discovering umami, our fifth taste, in the early 20th century, to understanding how umami sensory mechanisms and physiologic pathways [work] may have significant implications for human health."

NEED TO KNOW

The Tokyo-based Umami Information Centre (umamiinfo.com) is an excellent resource for more on the fifth taste.