Whether we’re raking them over charcoal at a tailgate party or broiling them in our oven on a scrap of aluminum foil, Americans love to cook and eat hot dogs. But one thing we can’t agree on is how to top them.

Bruce Kraig, author of the textbook on American hot dog culture, Man Bites Dog, says detailing the regional varieties—how they’re cooked and what’s on top—is like following the immigration patterns of our ancestors. “Almost every variety is ethnic,” he says. “They can be traced to newer immigration, from 1910 onward, namely the Greeks, Jews, Macedonians and Mexicans. Before that, hot dogs were just served plain.”

Because hot dogs were German to begin with, they were originally made by Germans and cooked the German way, on a flat griddle, and served with mustard and onions on a plain bun. “Americans love three things: meat, fast food and cheap food,” Kraig says. “Hot dogs have been embedded in our culture, in our mass entertainment, since the 1870s.” Hot dogs were a mainstay on boardwalks like Coney Island and at bicycle races, which were once hugely popular in the U.S. And of course, at baseball ballparks.

But Americans didn’t just eat hot dogs—the first prepackaged food—for fun, they ate them out of necessity: To the cities’ working class, hot dogs were an affordable and fast meal. Then as Greek and Jewish immigration increased, these two nationalities dominated the hot dog world. Even though both groups were mostly poor, they could afford to go into the food cart business. (Once they excelled in the food cart business, they could move on to bigger and better businesses, eventually making their way into the middle class. This is basically the history of New York’s Lower East Side and Chicago’s Maxwell Street.)

“Immigrants wanted to give their hot dogs a style all their own,” Kraig says. “That’s how these styles were established, over time, most of them since World War II.” Or the hot dog peddlers just wanted to cater to their market demands. Chicago dogs, for example, were once made of beef and pork. But in the early 20th Century, the working-class Maxwell Street, where hot dogs were popular, was the Jewish ghetto. So hot dog vendors removed the pork from the dogs to meet kosher requirements.

“The Greeks in Detroit in particular wanted to add value to their plain sausages, so they topped them with a sauce they brought from home,” he says. “It was a spicy, tomato-based sauce that included cinnamon, nutmeg and sometimes cumin. It’s the kind of sauce you’d put on a moussaka.” This sauce is now referred to as Coney sauce and it is used on Detroit Coney dogs to this day. In nearby Flint, Michigan, Slavic-speaking Macedonians ran the hot dog carts. Flint sauce included—and still includes—ground beef heart, which gives Flint dogs a distinct liver flavor.

In fact, the U.S. has dozens of classic, regional hot dog styles and many sub-styles underneath those. “There’s an expression: How many curries do you think there are in India?” he says. “Millions, because every housewife makes it slightly different. That’s how it is with hot dogs in America.”

The only thing all of these dogs have in common is that ketchup is seen as an immature topping; the topping that separates the adults from the kids. “If you order ketchup on a hot dog in Chicago, we revoke your passport,” Kraig says. “Chicago dogs are hot, sour, sweet and salty. You bite into that and you’ve got the soft bun, crunchy vegetables and the hot dog itself has a snap. All together it’s a mixture of flavors and mouth feel. You put ketchup on that and it ruins everything.”

As the expert on all things hot dogs, Kraig must consume a lot of hot dogs, right? “Actually I don’t,” he says. “There’s only so much salt you can eat.”

Above, some of the many wonderful ways we dress our franks across the country.

Alyson Sheppard is the resident hangover specialist at Playboy.com. Follow her on Twitter: @amshep