In my family, I grew up knowing that my parents would support me no matter the mistakes I made. Bad grades, underage drinking, becoming an English major? All could be forgiven. Unless, of course, I put ketchup on a hot dog. Then I’d be out on my ass.
In advance of the Fourth of July holiday, I emailed my dad to see if his opinions on hot dogs and ketchup had changed at all. "It is not that ketchup on hot dogs is inherently disgusting (although even the thought picture was enough for me to lose my appetite for breakfast)," he wrote back, before going into an intricate theory about why mustard is just better.
My personal favorite way to eat a (preferably spicy) hot dog is with sweet relish, mustard, and pickled jalapenos, but that’s not for everybody. Chicagoans famously like to put a pickle spear in the bun and top the whole thing with celery salt like some seriously fancy patriots. The sugary red substance known as ketchup is OK, too, if it accompanies mustard. But on its own, ketchup on a hot dog is considered by my clan to be a sign of childishness and disrespect.
Pretentious foodies agree. But does science? My dad's theory, though clearly right, is a mix of science, gut feeling, and mysticism. So I figured I should double check with the hard scientists.
Hot dogs come in different varieties, but usually share some general taste profiles: umami, saltiness, sweetness. Sure, you could put more sweetness on top of that if you're, I don't know, a child, but if you're an adult with an adult's palate, you probably want to complement that flavor. Mustard, in all its varieties, is characterized by a sharp vinegar and spice flavor, on the bitter and savory spectrum. Surely, science agrees that tangy is the best flavor to accompany something fatty, salty, and sweet?
"There is no basis to this," wrote Richard Mattes, distinguished professor of nutrition science at Purdue University, when I emailed him for his thoughts. "Note the popularity of Reese’s Peanut Butter Cups. Their appeal is sweet-salty combination."
Harrumph. Mattes' point is that hot dogs are mostly savory and salty, and there's a whole industry (snack foods, that is) devoted to combining salty and sweet into something people love. But, you know, that's just the opinion of one very well respected scientist who has studied this stuff for years. And look, the literature on taste does indicate that people who like sweet things more than savory things are less advanced. Don't get offended! That's just what the science says.
Babies may not actually have teeth, but they are born with a sweet tooth. That, according to Danielle Reed, a taste geneticist and Associate Director of the Monell Chemical Senses Center, is to encourage them to suckle breast milk, which is loaded with glucose (along with lots of other important stuff, like protein and fat). As babies, the most important thing for us to do is grow. "We like sweet because we need the calories," Reed says.
As people grow up, their tastes mature. "Our taste buds and olfactory sense change with age," Reed says, comparing it to our taste in other things, like art. "In childhood we love vibrant colors and then we get a love for more nuanced things, like contemporary art, so there is a sort of cognitive maturation that delights in more nuanced experience." Yes, yes, yes, yes, exactly. So appreciating bitter, complex, contrasting flavors—stuff like blue cheese and olives and mustard—is a sign of mature and better taste buds, right? Right?
Well, no. Reed says, actually, as we age our taste buds do change and get less sensitive to some things, but to imbue that process with a qualitative label is misguided. "There's a famous saying that in matters of taste there is no argument, which means you like what you like and I like what I like, and it's not a moral judgment on either of us," she says. Though, personally, Reed is a mustard person. She prefers the grainy type, a choice I greatly respect.
But what about the fact that I love my family and my family says mustard is best? What about that?
That makes sense, Reed says. Taste is, in some ways, hereditary. She studies how genes affect taste preferences, and tells me she could look at mine and pinpoint why I like certain flavors more than others. People who like more sugar in their coffee—or who, perhaps, like ketchup on a hot dog—may have genes that make their taste buds less sensitive to sweetness, so they need more of it to taste it. Everyone tastes things differently. "Some people can taste some things and others can't taste other things. That's unique for every person," she says.
Mattes adds that much of taste preferences are learned. Additionally, even if flavor balance is seen as the goal in dressing a hot dog perfectly (which it should be—let's be clear about that!), different types of hot dogs would require different toppings in order to achieve such balance. In some cases, if the hot dog is extra spicy and savory and salty, ketchup might (eesh, it pains me to write this) be the best way to complement it.
So no, science is not on my side in the argument that mustard is objectively best. This time. But, you know, my toddler son hates mustard. He loves ketchup—on all things, even cucumbers and blueberries. I love him anyway. I suppose it's time I learned to love and accept ketchup-on-hot-dog eaters, too. After all, the Fourth of July is about celebrating this country coming together. So eat your hot dog however you want, patriots. I'll stop judging you.
