Somewhere–probably buried in a time capsule beneath the Coney Island Cyclone–there must be a dusty, cobweb-covered tome that smells of smoke and mildew. And somewhere, deep within that book, there must be law–still in effect, but hardly ever evoked–that clearly states:

Hot dogs must be eaten with mustard.

Why is this, you ask? Well, there several possible reasons. One could be as simple as tradition: the Romans first used mustard, far as we know, and they brought it to Gaul. Europeans have long eaten mustard with meat, and probably brought the combo to the New World, way back when.

Then too, there was practicality: with all that vinegar, mustard doesn’t require refrigeration can be easily made available wherever hot dogs were sold.

But the real reason, of course, is that the flavor just ROCKS. That acidic tang with just a hint of heat slices through the smoky richness of the hot dog and makes your whole sandwich come alive. Throw in the sweet crunch of coleslaw, and you have a dog worth dying for.

That much, we can all agree on. But then comes the question that has plagued the ages: what kind of mustard?

Types of Mustards

While there are all sorts of sub-groupings (honeyed, organic, what-have-you), mustards can be grouped into 4 broad categories: yellow, brown, Dijon and deli mustards.

Yellow mustards seem to be the ones most closely associated with hot dogs, particular ball park franks and street carts. This makes sense, given the practical reasons listed above. It’s a traditional flavor, and one that many dog-biters expect to taste: tangy and a bit sour, with a hint of warm spice. Having said that, yellow mustard tends to be duller and more watery flavor on the dog than, say, licking it off the knife.

Not that any of you would be licking the mustard knife. But if you were the sort who did that, you might have the same complaint about some of the brown mustards available: spicy, tangy, and often with a kick of horseradish … but less aggressive on the dog than on its own. Still, a spicy brown mustard has more of a chance of nudging your sinuses a little, and the piquancy nicely complements the rich fatty flavor of the dog.

Deli mustards are kind of the more sophisticated older sibling of brown and spicy. Darker yet more golden-hues, typically punctuated with pits of seed, deli-styled mustards often serve up a sharper, more vinegary flavor that’s strong enough to hold its own against the sausage. The prepared versions, of course, don’t compare to the hand-made condiments you might find in a genuine New York delicatessen, but you’ll still score a pleasantly bold flavor with complex, spicy bite.

Then there is Dijon, a medium-spicy concoction typically made with white wine (hey, it’s French: what did you expect?). While most of us aren’t going to request it from the window of our chauffeured Rolls-Royce, Dijon mustards tend to be more complex while also being creamier and smoother. Some tend toward saltiness, too; that can work well with some franks, but if your dog already has its fair share of salt (as most grocery-store varieties do), slathering it with Dijon can be too much.

The Customer Is Always Right

So which is the best hot dog mustard? It totally depends on what you’re expecting. Connoisseurs are more likely to appreciate the spice and bite of a brown or deli-style mustard. But for the bulk of Americans, it seems, traditional yellow is the mustard most commonly expected when ordering up a red-hot. And as the saying goes, The customer is always right (not really), just so long as mustard fits into the equation somewhere.

We’re pretty sure it’s the law.