Umami: why the fifth taste is so important

The strong savoury flavour that makes everything from spag bol to Marmite so hard to resist may serve a vital evolutionary purpose. 

We could even use it to fight malnutrition. Pass the parmesan

Parmesan is probably the most umami ingredient in western cookery.

I am often flabbergasted when I think about how humans came to develop such complex culinary skills. Granted, 1.8m years have passed since our ancestor, homo erectus, began to cook. But still, leavened bread! That was one hell of a happy accident.

Our predilection for umami – the only recently recognised (by western scientists) "fifth taste", after salt, sweet, sour and bitter - is a fascinating piece in the jigsaw of our gastronomic evolution. Since studies confirmed just a few years ago that our mouths contain taste receptors for this moreish savoury taste (the other four "basic tastes" had been widely accepted for, ooh, a few thousand years), so much in the history of recipes suddenly makes sense. 

Umami is why the Romans loved liquamen, the fermented anchovy sauce that they sloshed as liberally as we do ketchup today. It is key to the bone-warming joy of gravy made from good stock, meat juices and caramelised meat and veg. It is why Marmite is my mate.

Escoffier, the legendary 19th-century French chef who invented veal stock, felt sure that a savoury fifth taste was the secret of his success, but everyone was too busy gorging on his food to take much notice of his theories. Fast forward to the 21st century and many cooks are delighted to finally see proof of what they had instinctively known. Massimo Bottura, whose restaurant in Modena is ranked fifth best in the world, served the first incarnation of his dish five ages of parmigiano reggiano in different textures and temperatures in 1995. More recently, however, Bottura says that the discovery that parmesan is probably the most umami ingredient in western cookery has enhanced his appreciation and understanding of the dish. "Five textures, five temperatures and five levels of umami," is how he now views it.

Putting a name to a taste

Umami has been variously translated from Japanese as yummy, deliciousness or a pleasant savoury taste, and was coined in 1908 by a chemist at Tokyo University called Kikunae Ikeda. He had noticed this particular taste in asparagus, tomatoes, cheese and meat, but it was strongest in dashi – that rich stock made from kombu (kelp) which is widely used as a flavour base in Japanese cooking. So he homed in on kombu, eventually pinpointing glutamate, an amino acid, as the source of savoury wonder. He then learned how to produce it in industrial quantities and patented the notorious flavour enhancer MSG.

What gives good glutamate?

Cheese and cured meats have umami in spades. 

A quintessential example of something umami-tasting, says Paul Breslin of Monell University, who was among the first scientists to prove the existence of umami taste receptors, is a broth or a soup: "Something that has been slow-cooked for a long time." Raw meat, he points out, isn't that umami. You need to release the amino acids by cooking, or "hanging it until it is a little desiccated, maybe even moulded slightly, like a very good, expensive steak". Fermentation also frees the umami – soy sauce, cheese, cured meats have it in spades. In the vegetable kingdom, mushrooms are high in glutamate, along with those favoured by children such as petit pois, sweetcorn and sweet cherry tomatoes. Interestingly, human milk is one of the highest MSG-containing mammalian milks.

Magical flavour-bomb maths

Double cheeseburger with all the trimmings: ménage à trois. 

So why is bolognese sauce with cheese on top, or a cheeseburger with ketchup so finger-licking good? Because, says Laura Santtini, creator of the umami condiment Taste No 5 Umami Paste, when it comes to savoury, "1+1=8". In the simplest terms, umami actually comes from glutamates and a group of chemicals called ribonucleotides, which also occur naturally in many foods. When you combine ingredients containing these different umami-giving compounds, they enhance one another so the dish packs more flavour points than the sum of its parts. This is why the cooked beef, tomato and cheese in the above examples form a ménage à trois made in heaven. And why ham and peas is a gastronomic no-brainer. And, oh dear, why it's hard to stop popping Smoky Bacon Pringles.

Why we love umami

Just as humans evolved to crave sweetness for sugars and, therefore, calories and energy, and loathe bitter to help avoid toxins, umami is a marker of protein (which is made up of amino acids, which are essential for life). This begs two interesting questions. First, why is our innate penchant for umami best served by cooked or aged foods? Breslin's answer is that cooking or preserving our main protein sources detoxifies them. ""Part of the great digestion formula," he says, "is not only the ability to procure nutrients, but it's to protect yourself from getting sick while you do that. If you don't get proper nutrition you can live to see another day, but if you're poisoned, it can end it for you right there." Second, why are some fruits and vegetables that are low in protein, high in glutamate? Some cases, such as mushrooms, says Breslin, we cannot explain. However, for others, such as tomatoes, it could be the same reason why fruit is so sweet. "The sugar is there so you grab the fruit and spread the seeds around. It could be that the mixture of sugar and glutamate in some of these foods is there to make them extra attractive."

A force for good?

Lacing cheap, fattening, non-nutritious foods with MSG to make them irresistible is clearly not responsible, but some argue that glutamate can be used responsibly to good effect. Breslin says one of his key motivations is finding ways through taste research to feed malnourished people. "What you want," he says "are things that are very tasty that kids will eat, that will go down easy and will help them." Meanwhile, Professor Margot Gosney, who chairs the Academic and Research Committee of the British Geriatrics Society is "looking into increasing the umami content in hospital food," to make it more appealing to older people, without overdoing the salt.

When I first learned about the fifth taste, I became obsessed, seeking it out in ingredients and experimenting. However, not everyone is convinced that umami should even be classified as a basic taste. Professor Barry Smith of London University's Centre for the Study of the Senses queries why "we need neuroscience and the Japanese" to alert us to it, when tastes such as salt and sweet are clear as day. "If you think of what has umami," he says, "it's not obvious that there's something in common with all these things," and in lab tests, westerners struggle to consciously detect it."