But what does umami taste like?

As a kindergartener, I was taught there were four basic tastes: sweet, salty, sour, and bitter, which we represented by filling in a map of the tongue with crayon.

Like many things taught in kindergarten (except for the alphabet), it turns out this is not true. The idea of a “taste map” — that certain regions of tongue detect certain flavors — has been enthusiastically debunked. Also, there are not four basic flavors, but (at least) five: sweet, salty, sour, bitter and umami.

If you eat food, you have experienced umami. If you read about food, you have heard umami is good. A review of a New Orleans restaurant, for example, sings the praises of a brisket that packs a “landslide of back-of-the-mouth umami.” A review of a San Diego restaurant raves over the “rich umami flavor” of particular tomatoes. As the New Yorker has extensively chronicled, Adam Fleischman’s burger chain — Umami Burger — is built entirely on the principle of maximizing umami.

And yet, like pornography, umami is hard to describe in words. In the New Yorker, Hannah Goldfield defines it as “that deep, dark, meaty intensity that distinguishes seared beef, soy sauce, ripe tomato, Parmesan cheese, anchovies, and mushrooms, among other things. It hits the back of your throat and leaves you craving more.” It is deliciousness — umami, she explains, roughly translates to “deliciousness” in Japanese — but it is not just any deliciousness. Umami is a specific type of deliciousness, the savory thread connecting mushrooms to ripe tomatoes.

So it’s weird that the purest carrier of umami we can access has been maligned for decades. Umami mostly does not exist in isolation, except in one form: MSG, a pariah of the spice aisle.

As Helen Rosner wrote recently, also in premier umami publication the New Yorker, a lot of people have been misguidedly avoiding MSG (monosodium glutamate). Thanks to an unfortunate cocktail of racism, xenophobia, and a disproportionately influential 1968 letter to the editor in the New England Journal of Medicine, many believe — in most cases, totally erroneously! — that MSG has made them feel sick. (FiveThirtyEight has a great breakdown of why this could be.) But it’s a bummer. Our food could have tasted so much better this whole time.

I know all this. And yet, I was recently at a grocery store selling “umami hot sauce,” and I could not envision what that would taste like or how I would use it. So I reached out to Gary Beauchamp, president and director emeritus of the Monell Center, which is devoted to the study of taste and smell, to help explain what we know, what we don’t, and what a “basic taste” is in the first place. Our conversation has been condensed and edited for clarity.

To start with the most basic question here, what is umami?

That’s not so simple. So the historical belief about taste — and taste I’m distinguishing from smell — is that it’s one of the five classic sensory systems, which was thought by Aristotle, and even before that, as consisting of four basic tastes: sweet, sour, salty, and bitter. And they’re kind of called “basic tastes” because they’re essentially independent of each other in the sense that you can’t make something sweet by mixing salty, sour, bitter.

They’re like primary colors.

Like primary colors, exactly right. But they don’t blend like primary colors do. If you mix sugar and salt, you don’t get a third thing, the way you would if you mixed two colors and got a different color that you wouldn’t necessarily predict is the mixture of the two.

Until fairly recently, it was agreed by most people in the research field that there were these four independent taste qualities. And then, in 1908, Kikunae Ikeda, a Japanese chemist, made the discovery that glutamate — and the sodium salt of glutamate in particular — had this taste which he perceived to be subtle but unique.

And he argued that, like the other primaries, you couldn’t make this taste out of other tastes. It was separate. Based on that, he formed a company, which sold a lot of sodium glutamate, because it really worked in foods.

That sodium glutamate product is MSG, the often (unfairly) maligned ingredient associated with Chinese restaurants, and is known for making food more delicious. So is MSG ... pure umami?

You could say that. The idea that there was a separate taste was based on the discovery that pure MSG — sodium salt of glutamate, which is the most common amino acid in the body — has a different taste that is characteristic of savoriness, and that taste different than sweetness, is different than sour, and it’s different than saltiness, and is different than bitterness.

Umami, in a sense, is more subtle than those other four. It’s not found very much by itself in nature. I mean, there’s pure salt in nature everywhere. There are some pure sweet things. Honey, sugarcane, whatever. And of course, many things are bitter; sour is acidic things. The source of those is clear. This is not quite so distinctive.

But then came a revolution in the taste field, amazingly less than 15 years ago, which was the discovery of the actual receptors that are involved in taste. Bitter receptors — the molecular mechanism for bitter taste — was discovered. The molecular mechanism for sweet taste, or at least part of it, was discovered. Salty taste is still kind of questionable, but now we know something about the molecular mechanism for that. And there was an identified set of receptors in the oral cavity that seemed to be particularly and specifically responsive to glutamate.

So how was it identified in the first place?

Part of the traditional Japanese diet is a simple soup stock made with seaweed, and perhaps a fish component. And it gives a very savory kind of flavor, which is quite pure. It’s the basis for many Japanese foods; you see it in things like soy sauce.

The story is that [Ikeda] was eating this soup, and he said to himself, “There’s something really interesting in there, I wonder what it is.” So he went into his laboratory and made some of this soup stock out of the seaweed, and then tried identify what was causing this sensory impression, and he identified it as glutamic acid. Glutamic acid itself is sour with some umami taste to it, but if you neutralize it — particularly with sodium salt — then it’s sodium salt of glutamate, or MSG, and this has sort of the pure savoriness.

What other foods, besides seaweed, have that umami taste?

Many foods around the world contain it. For example, there are high concentrations of it in many cheeses, and these cheeses are the most attractive ones. It’s in certain mushrooms. It’s certainly found in meat as well; seafood in particular has high levels. Tomatoes have very high levels, for reasons that are unclear to me. It’s in our diet everywhere; it’s just that it’s not by itself. The only place it’s by itself is if you use the powder. If you’re going to a grocery store to buy Ac’cent, you’re buying MSG.

Do you think of umami as a basic taste?

I think umami is kind of a fifth basic taste. I think it’s distinctive; I agree with that. It seems to be sought out in all sorts of cultures, even when they don’t know they’re seeking it out; even when they’re using other things to generate it. I would say it’s a basic taste, but a different basic taste.

To get back to the other thing you raised — what’s the sensory response? First of all, you can go buy Ac’cent and then try it. That’s the best way. You try the pure stuff, and what you’ll find is — I shouldn’t tell you, because you’re not supposed to be biased — but you’ll find that it tastes salty, because there’s sodium in it. But the other thing you’ll find is that you don’t particularly like it. It appears that under most circumstances, by itself, it’s not attractive, and so we don’t eat it alone.

We know babies like pure sugar. Babies like pure salt, and basically, they come to like sugar and salt with foods, rather than by themselves. But for umami, there’s no evidence we like it by itself. It seems to have to be with some other food, and it’s a puzzle as to why that is.

The other sensory response I think you’ll find is that, in addition to what you and I would call a taste, it creates a mouthfeel. It creates a fullness. It creates a feeling of coating the mouth in a way that gives you the impression — it gives me the impression, at least — that it is thicker and more full-bodied. So by adding MSG to foods, you not only get this taste component; I think you add a feeling component.

I feel like “umami” gets thrown around in a very unclear way. Recently, I was at a store where they had “umami hot sauce.” What does that taste like? I don’t know. Whereas if someone tells me a cake is very sweet, I know what that means.

The best thing to do is a demonstration, where you take, say, a soup stock that’s very low in glutamate, and you taste it, and then you add glutamate to that soup, and you taste that, and you see a remarkable difference. Part of the difference will be in this flavor, which seems to be chicken broth-like, but the MSG makes it more like that. Plus, you’ll have this mouth-feel. That’s what umami is, according to the original definition.

If you do this demonstration for yourself, the thing that’s pretty striking about it is it works on almost everybody. You can really tell the difference. It would be like adding sugar to something, almost. Not quite as good as that; it’s more subtle than that. But it’s very clear.

I tried the experiment, only with vegetable stock (Beauchamp approved; I am a rule-follower, although I used a brand of MSG called “Splendid Spices,” rather than the classic Ac’cent, or Ikeda’s even more pure Ajinomoto), and the difference was stark. Rosner described the “savory chemical magic” of MSG as best used on occasions when “you just want something to taste like itself, only transcendently better.”

Without MSG, my mediocre broth was very mediocre. With it, it was richer and fuller, still vegetal, but with a meaty depth; not different, exactly, so much as better, like an Instagram filter for food. The un-doctored version felt watery by comparison, like it was missing something. Which it was: umami, in the form of MSG.