The Frontal Cortex


I’m a ketchup fiend. When I was a little kid, I was famous for squirting my plastic bottle of Heinz on everything, from spaghetti to vanilla ice cream. I’ve seen become slightly less disgusting – I no longer eat frozen dairy products with the condiment – but I still go through a disturbing number of ketchup packets when eating fast food. (French fries are a near perfect food, but they really are so much more delicious when coated in that sticky-sweet red sauce.)

So I was intrigued when Meg Favreau, in The Smart Set, wrote a short article about our lack of ketchup options, which is especially surprising given what’s happened to other condiments. After all, the typical supermarket has hundreds of different mustards (Dijon, whole grain, beer mustard, plain yellow, horseradish, etc.) but only a few alternatives to the classic version of ketchup. (I’m devoted to Heinz, but I’m not sure I could reliably tell the difference between Heinz, Hunts, Del Monte and the generics. I’ve got a pretty dumb tongue, which is probably why I was putting ketchup on ice cream in the first place.) This is the culinary paradox first identified by Malcom Gladwell, in a wonderful 2004 article:

In the gourmet-ketchup world, there is River Run and Uncle Dave’s, from Vermont, and Muir Glen Organic and Mrs. Tomato Head Roasted Garlic Peppercorn Catsup, in California, and dozens of others–and every year Heinz’s overwhelming share of the ketchup market just grows.

Why is classic ketchup such a perfect product? Why am I so uninterested in more ketchup options? I have five different kinds of mustard in the fridge, and I’m normally averse to products with a heavy dose of high fructose corn syrup, and yet I’m extremely devoted to my Heinz.

The answer, I think, returns us to the tongue. I know there are hints of clove and cinnamon and brown sugar in my ketchup, but let’s be honest: they don’t really matter. Those are subtle flavors, detected by odorant receptors in my nasal passages, and ketchup is all about three elemental tastes: sweet, sour, and umami. (Here’s an experiment to conduct the next time you have a cold: eat a tablespoon of ketchup. It will still be delicious, which goes to show that it’s one of those rare foods that doesn’t depend on the nose.) The sweet element is obvious: ketchup has a disturbing amount of sugar in it, most of which comes from corn, not tomatoes. The sour element is also pretty straightforward: every good ketchup contains vinegar, which gives it that necessary tang. But the most important taste in ketchup, and the reason it’s such an indispensable condiment, has to do with umami, or the fifth taste sensation first discovered by the Japanese chemist Kikunae Ikeda in 1907. It turns out that our mouth contains multiple receptors that respond to the presence of L-glutamate, an unraveled form of the most prevalent amino acid in most living things. Here is how I describe umami in my first book, Proust Was A Neuroscientist:

The first umami receptor was discovered in 2000, when a team of scientists noticed that our tongue contains a modified form of a glutamate receptor already identified in neurons in the brain (glutamate is also a neurotransmitter). The second sighting occurred in 2002, when another umami receptor was identified, this one a derivative of our sweet taste receptors.

These two separate discoveries of umami receptors on the tongue demonstrated, once and for all, that umami is not a figment of a hedonist’s imagination. We actually have a sense that only responds to veal stock, steak and dashi. Furthermore, as Ikeda insisted, our tongue uses the taste of umami as its definition of deliciousness. Unlike the taste of sweet, sour, bitter and salty, which are sensed relative to each other (this is why a touch of salt is always added to chocolate, and why melon is gussied up with ham), umami is sensed all by itself. It is that important.

This, of course, is perfectly logical. The tongue craves sweet things because the body requires glucose for energy. Likewise, we love the flavor of denatured protein, because, being protein and water ourselves, we need it. Our body produces over 40 grams of glutamate a day, so we constantly crave an amino acid refill. In fact, we are trained from birth to savor umami: breast milk has ten times more glutamate than cow milk. The first taste we ever know is deeply umai, preparing us for a lifetime of eating cheese, ripe tomatoes, seared steak and deglazed pans auces. The tongue loves what the body needs.

What does umami have to do with ketchup? It turns out ketchup is an umami speedball. Ripe tomatoes are full of L-glutamate, and so when all those tomatoes are cooked and reduced, and then cooked some more, the end result is a sauce brimming with delicious amino-acids. In fact, it is the umami note in ketchup – a mouth-filling savoriness, a low basso profundo note – that I most crave when squirting Heinz onto my fries.* The deep-fried potato starch is delicious yet incomplete – it is the umami of ketchup that completes it.

So here’s my theory of why ketchup doesn’t benefit from fancy alternatives, while mustard does. Ketchup is a primal food of the tongue, relying on the essential triumvirate of sweet, sour and umami. As a result, nuance is unnecessary – I don’t want a chipotle ketchup, or a fancy organic version made with maple syrup. I just want the umami sweetness.

Mustards, in contrast, are foods of the nose, which is why we seek out more interesting versions. I like tarragon mustards, and dark beer mustards, and spicy brown mustards, because they give my sandwiches an interesting complexity. They give my nasal receptors something to sense.

So here is my larger theory: mustards and other foods that we experience through smell (and this includes most foods, since 90 percent of taste comes from the nose) benefit from gussied up versions. We want dozens of different ice cream flavors, hazelnut-blueberry coffee and an apple-cinnamon cheerios. In other words, we want to take advantage of all those unique nasal receptors leftover from mammalian evolution. (Nearly three percent of the human genome is devoted to our nasal receptors, many of which no longer work.) But foods that rely on the tongue for pleasure – I’m thinking here of ketchup, and grilled steak, and parmesan cheese – don’t benefit from variety. I don’t want a sauce on my steak and I don’t want cumin flavored parmesan. Such additions are distractions. They take away from the simple pleasures of the tongue.

*And ketchup isn’t the only condiment that depends on umami. Fish sauce, being composed of rotten anchovies, is nothing but stinky umami liquid. And what about Marmite? That “yeast extract spread” contains more umami per 100g than any other processed food product. And yet it still tastes like tar.


  1. #1 Janne
    August 1, 2009

    How about an experiment: get a small bag of MSG, put some in a salt shaker, and try using it instead of ketchup for, say, two weeks or so. If you’re right you’re going to get the same kind of satisfaction ketchup is giving you, but with a much greater variation of flavour (since it won’t overwhelm the base flavour of the food the way ketchup does). If it leaves you woefully unsatisfied, on the other hand, you’ll know umami is not the principal reason for your habit.

  2. #2 Rich
    August 1, 2009

    Quick question: in terms of the umami flavour, is there a difference between searing and grilling? ie. do you think searing creates more umami taste than grilling which has less browning? thanks – excellently enlightening blog by the way

  3. #3 Ida
    August 1, 2009

    Since I saw the documentary film FOOD,INC I’m not eating catsup nor chili sauce which I used to like, too.

  4. #4 chezjake
    August 1, 2009

    As you’re probably aware, mushrooms are another excellent source of umami taste. And I’ve had several excellent mushroom ketchups (with no tomato at all in them). They tend to be not as sweet as tomato ketchup, but seem every bit as satisfying to my taste. (Probably easier to find mushroom ketchups in the UK than here.)

  5. #5 Giovanni Rodriguez
    August 1, 2009

    Jonah — if you haven’t already done so, check out the ketchup chapter in Jeffrey Steingarten’s THE MAN WHO ATE EVERYTHING. He makes the case that ketchup is the greatest sauce ever invented. There might be something there to support your theory.

  6. #6 Comrade PhysioProf
    August 1, 2009

    Awesome post, holmes!

  7. #7 Shelby Davis
    August 2, 2009

    Yes! Yesterday I was enjoying some gourmet fries made of yams at some fancy-pants restaurant, and they brought out a dish of something like Mae Poi for dipping. I, too, slather my fries in ketchup, but I left these naked after a few tastes–something was just not right. There was no umami!

  8. #8 Arj
    August 2, 2009

    You may have overlooked “texture” in all of this… one reason for Heinz’s popularity is likely the highly-vaunted thickness of their product. The gloppiness/clinginess of ketchup in general is probably a factor in its taste and popularity (at least I don’t think a really runny ketchup would be nearly as popular).

  9. #9 G. Randolph Mayes
    August 2, 2009

    Most of us don’t want to just eat dollops of ketchup. It’s a condiment, which means that most of us experience it as mixing well with other foods. So it doesn’t quite make sense to say that the reason we like plain ketchup best is because other flavors we’ve tried adding to it are distracting. I, for example, really like both ketchup and jalapenos on my burgers, and would probably like a jalapeno flavored ketchup for that particular application. But it wouldn’t extend to fries. So I think a better explanation is that plain ketchup is both deeply satisfying and multi-purpose. Adding flavors may improve it for specialized uses, but it ruins it for the others, so it isn’t worth it.

  10. #10 Steve Silberman
    August 3, 2009

    I lived with a professional chef for 11 years. We ground our own flour, grew our own lettuce and peas, and cured our own duck proscuitto. And once, we made our own ketchup.

    The simmering pot of heirloom tomatoes (or was it San Marzanos?), vinegar, spices and sugar filled the house with an intriguing aroma. It took hours, boiling it down to a brownish paste. And when it was all over, we had a spicy condiment that tasted somehow ancient, resonant of old wharves, ship barrels, and the Silk Road or something. And who cared? Not us. We went back to Heinz. It was much better.

    Note: there are significant differences between store-bought ketchups. Heinz is, you know, quite good. The newish Muir Glen (they also make great canned tomatoes) is good too. Some of the others, meh.

  11. #11 Comrade PhysioProf
    August 3, 2009

    The newish Muir Glen (they also make great canned tomatoes) is good too.

    Agreed that they make great canned tomatoes. They went into this dish last night:

  12. #12 El guapo
    August 4, 2009

    how cute you dumping ketchup on everything when you were a child, it makes my heart sob…

  13. #13 LRA
    August 4, 2009

    Wow. If you ever make it down to Texas (where I live), I suggest you check out Whataburger ketchup!!! It is the best! 🙂

  14. #14 David Kerlick
    August 7, 2009

    Was garum “the ketchup of antiquity” and one of its principal trade items, also high in umami? Nowadays its rotting fish taste is an acquired one.

  15. #15 Martin
    August 10, 2009

    Marmite with butter on crisp toast–sublime umami goodness.

  16. #16 kathleen
    August 10, 2009

    Try a bit of honey (manuka is good, also from kiwi land) with your marmite.

    Also, tomato sauce from NZ or AUS are interesting variations on traditional American ketchup.

  17. #17 Ned
    August 11, 2009

    Welcome back to LA.
    If you can find it anywhere, you can find it here.
    Thanks re ‘umami’ somehow not previously perceived.
    Try “Talpa” on Pico; Father’s Ofice on Montana; and
    Intelligentsia Coffee [Venice, LA]

    o mei

  18. #18 Faport International
    August 20, 2009

    really awesome

  19. #19 SSB120
    September 8, 2009

    It’s really interesting to think about how even though we think that we consciously make certain choices and decisions in our lives, these decisions are really made for us by our bodies. This is a great example of that. It’s intriguing, to say the least, to think about how foods that we think “taste good” really only taste that way because they are necessary staples of our diets, and therefore our bodies crave them.

  20. #20 ari-free
    January 3, 2010

    here’s a simpler explanation: ketchup is American pop culture for the lowest common denominator. It is like McDonald’s and Coke. Making a gourmet version of ketchup would be like making a gourmet version of American cheese or fish sticks.

    Mustard, on the other hand, goes all the way back to France and has deep gourmet roots. Therefore it lends itself to more creative varieties.

  21. #21 ari-free
    January 3, 2010

    the theory is also refuted by the fact that there are many varieties of tomato based pasta sauces on the market.

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