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.