Secret Sauce

Umami is what makes savory foods so delicious.

pizza pizza very good.
Savor the flavor.

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Umami may be the culinary buzzword of the 21st century. The term combines the Japanese characters for delicious and taste, and it’s the name for the fifth basic taste, after sweet, sour, bitter, and salty, an otherwise difficult-to-describe kind of savoriness associated with seared meats, miso soup, cheese, and tomatoes. To Western ears, the word is soothing, mysterious, evocative. Umami Burger, the growing, Los Angeles-based chain, has turned it into a global brand, and it pops up everywhere: on the menus of high-end restaurants, on food packaging, and discussions of the future of cuisine. The word, both appealing and elusive, is also the name of a sensation that, branding and popularity aside, we still really don’t know that much about. 

The story of umami’s discovery is famous in the annals of food science. A century ago a University of Tokyo scientist named Kikunae Ikeda was contemplating the taste of his daily lunch of kombu dashi, a kelp broth that’s a staple of Japanese food. He became convinced that his experience of its savoriness was a biologically determined taste for … something. 

So he set out to find what that something was, chopping up and testing a heavy block of dried seaweed. Eventually he linked the savory taste to the salt of glutamate, a type of amino acid present in a lot of foods—and in the biology of living creatures in general. The sensation itself, however, is more obscure than that from the other basic tastes. Savory or meaty are often used to describe it. But if you sip some of those amino acids in a water solution, they won’t taste like much of anything. Often umami simply enriches other flavors. This effect is part of what makes pizza, with its umami-rich cheese-and-tomato combination, such a seductive, potent dish. 

Monosodium glutamate, the flavor enhancer used by food companies and some Asian restaurants, triggers the umami sensation. In the 1960s MSG was linked to a headachey feeling called “Chinese restaurant syndrome,” and it has been a controversial additive that many people avoid. But scientists have not found a consistent link between it and headaches or other health problems.

Umami synergy is a remarkable phenomenon. It harmonizes tastes and aromas, the two main components of flavors, heightening both. In one experiment at Oxford University, volunteers sipped an umami cocktail (water with MSG and an associated molecule that enhances its effects), then sniffed a vegetable aroma. Separately, each was bland or unpleasant; together, delicious. When the volunteers’ brain activity was mapped in a fMRI scan, neurons in the frontal cortex associated with flavor and pleasure ignited in far greater numbers, and for a longer time, than you’d expect by adding up the separate effects. 

You can see the appeal for chefs and food formulators. But scientists are still baffled about how this happens—and why.

The other four “basic” tastes are all (or appear to be) linked to survival. Each ignites a special circuit of synapses through the brain, triggering a specific, conscious sensation and a strong reaction. Sugar is an essential nutrient, so we perceive it as tasty and sweet. We can’t survive without salt, but it’s dangerous to eat a lot of it, so it tastes good in small amounts, bad in large ones. Bitterness denotes a potentially toxic chemical. And sourness is a sign of acidity, associated with rot. 

What is umami for? Nobody really knows. 

Ikeda declared it was the “protein taste,” since amino acids are the constituents of proteins. Indeed, it would make sense if we did have taste for proteins, since they’re an important part of our diets. But umami receptors don’t detect proteins. Raw meat—what a protein taste should be all about—is not rich in umami. It takes roasting or grilling to bring out the glutamates and unleash the savoriness. Glutamates themselves play important roles in human biology. Breast milk is full of them, perhaps to provide a flavor boost to encourage suckling. They make it possible for the neurons in our brains to fire. They aid the digestive process, and the small intestine is lined with umami receptors. But the body manufactures plenty of glutamates itself. 

Umami is, if anything, a fringe benefit of civilization. Cooking, curing, and fermentation all unleash waves of umami—supercharging many other flavors in the bargain. There’s far more umami in our diets than in those of early humans, or even diets just prior to the birth of civilization, which is when people began making fermented foods in a systematic way. This was fantastic for early connoisseurs: These new foods were, as a whole, many times better-tasting than stuff their immediate hunter-gatherer predecessors could whip up. Now, 12,000 years later, we’ve entered a new and still richer stage of umami immersion.

Read more about flavor, from its origins at the dawn of life, through the rise of civilization, up to the strange latter-day sensations created by the food system, in Tasty: The Art and Science of What We Eat.