You'll find an all-mustard vending machine and thousands of jars from around the world at the National Mustard Museum

“I am probably the first and only person in the world who has devoted his life to mustard obsession, mustard fandom, mustard love,” Barry Levenson, founder and curator of the National Mustard Museum in Middleton, Wisc., tells Yahoo Lifestyle. And there’s really no doubting he’s correct.

His museum, open for nearly 30 years, is awash in tones of yellow, its shelves stuffed with over 6,200 mustards from all 50 states and 90 countries, plus 500 old mustard tins and a slew of old mustard pots, ads, mustard-themed art, an all-mustard vending machine, and a children’s book Levenson wrote, called “Mustard on a Pickle.”

Barry Levinson in his National Mustard Museum. (Photo: Yahoo Lifestyle)

“I can blame it on the Boston Red Sox,” explains Levenson, wearing a yellow T-shirt that says, “Squeeze the Day, Carpe Dijon.” In 1986, he explains, the Red Sox were in the World Series and close to winning, but then they lost it all. “I was so depressed,” he recalls, and, unable to sleep, he got in his car and drove to an all-night supermarket, where he found himself in the condiment aisle, standing in front of the mustards.

“Suddenly, I heard a voice,” he recalls. “‘If you collect us, they will come.’”

Since the start of his obsession, he’s probably tasted about 3,000 different mustards from all over the world. But don’t ask him which is his favorite.

“It’s like asking, ‘Who’s your favorite child?’” Levenson says.

Also, he adds, “it depends on what I’m eating. It’s like, ‘What’s your favorite wine?’ Well, ‘What are you eating with it?’”

Levenson doesn’t care for ketchup.

During the time of his “calling,” he was working as an assistant state attorney general in the Wisconsin criminal appeals division. And, he notes, “As far as I know, I am the only, certainly the first, lawyer to have argued a case at the U.S. Supreme Court with a jar of mustard in his pocket.”

He had grabbed the tiny jar when leaving his hotel and noticing it on a room service cart. It was one he didn’t already own, and he stuck it in his pocket. He did, of course, win the case.

Items bearing the logo of Levinon's invention, Poupon U. (Photo: Yahoo Lifestyle)

“It’s not that I didn’t like my job,” Levenson says. “I guess it was my midlife crisis that called to me, and said, ‘There’s more to it than just being a lawyer.’”

Part of that is now selling is the uniquely-branded collection, “Poupon U: America’s Mustard College” shirts, hats, mugs and toilet seats.

“People say, ‘You’re kinda nuts, aren’t you?’ I say, ‘You know, I don’t take that as an insult at all… This is my version of sanity.’ I’m OK with it.”

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