Uncle John knows pretty much everything—and if he doesn’t, he heads his massive research library, or puts one of his many associates on the case. So go ahead: In the comments below, ask Uncle John anything. (And if we answer your question sometime, we’ll send you a free book!) This week’s question comes from reader Pat B., , who asks…

Why don’t McDonald’s and Burger King sell hot dogs?

Memorial Day is almost here, and with it comes summer, and with that comes grilling season. It’s one of the unofficial “big three” barbecuing holidays of the summer, along with Independence Day and Labor Day. Nothing tastes better than a fire-grilled hot dog eaten in the warm sun. And maybe those summer weenie roasts are all the better because hot dogs are a special treat—you can find them ominously rotating for hours on end at a convenience store, or at a Nathan’s if you live on the East Coast, but other than that, hot dogs are conspicuously absent from the American burger-centric fast-food landscape.

It hasn’t always been that way.

Ray Kroc didn’t start McDonald’s—he was a milkshake machine salesman who guided the company into the lucrative field of franchising the burger stand. In his 1977 memoir, Kroc wrote of his disgust and displeasure for selling hot dogs. “There’s no telling what’s inside a hot dog’s skin, and our standard of quality just won’t permit that kind of item.” Result: no “McHotDog.” Except there’s at least one McDonald’s outlet that does sell the McHotDog: the one inside of the SkyDome in Toronto, where the Blue Jays play.

Hot dogs used to be a regular menu item at Burger King, in the 1970s and 1980s. They stopped selling them in the late ‘80s because sales weren’t good.