It's an hour before opening, and the bar at Marvel Bar in Minneapolis is lined with thirsty pupils. Marvel's resident American whiskey expert (yes, they have such a person) is explaining the nuances between the four spirits in front of them, breaking down whiskey jargon and offering tasting tips to his students.

"This may look funny," said teacher and bartender Tyler Kleinow, instructing the class to hold their mouths open slightly when tasting. "But there's a lot of things I do when I drink whiskey that make me look funny."

As cocktail culture has grown in the Twin Cities, a few bars have organized semiformal cocktail classes. Marvel started hosting tippling tutorials about 18 months ago. Typically, each class — held on the second Saturday of the month — focuses on a specific cocktail, such as the Manhattan or the Aviation.

"It'd be hard to talk about a martini for an hour," said Pip Hanson, Marvel's beverage director, who teaches most of the classes. "So what we generally try to do is show what the drink came from — maybe make an example of a historical precedent and then what came afterwards, or different styles of that drink."

Monthly cocktail classes at Parlour in Minneapolis began this spring, and bar manager Jesse Held added a second class, devoted to rum, in May. The spike in cocktail enthusiasm is similar to the foodie craze that came before it, Held said. "People aren't going out to restaurants anymore just to get drunk and full. They're going out to have experiences, and that's bleeding over to the bar side," he said.

Organizers say those who've signed up for classes range from neophytes to hyper-literate cocktail nerds. At Marvel, Hanson says they try to appeal to beginners by distilling the subject matter into the simplest form possible. But they will happily field Advanced Placement questions about dilution rates, ice types or obscure spirits. After a summer vacation, Parlour will offer "graduate-level" classes in September aimed at more serious home bartenders.

Joshua Zents of St. Paul took a taste test.

Back in April, Kristi St. Charles, 28, rounded up a few girlfriends for a tasting/seminar put on by the Easy & Oskey bitters makers and South Lyndale Liquors at the Black Forest Inn. The Minneapolis woman and her crew were intrigued by the $20 event, which included small pours of five different cocktails. "We all like a good cocktail, and it seemed like an excellent way to spend a Wednesday evening," she said, as the group lingered afterward, chatting and finishing their drinks.

Conversely, the freewheeling event led by Dan Oskey and Erik "Easy" Eastman drew seasoned DIY bitters makers Mike Hoffman and Devin Smith, both of Minneapolis, who hoped to glean pointers from the pros.

Oskey has taught cocktail classes in various formats for four years. The former lead barman at the Strip Club, who now heads Hola Arepa's bar program, wants to expand people's palates and help them overcome negative experiences they may have had with certain spirits. (That night at the Black Forest, one of St. Charles' friends buried her rum bias.)

The first class he ever led was for an architecture studio's holiday party. Initially, it was going to be dry, but bartenders don't really do "dry."

"They basically just wanted me to lecture," Oskey recalled. "I was like, 'You know, you guys, this is a lot more fun if we're drinking.' So we busted out the booze and started talking about it. It's about understanding and broadening your horizon."

There's no cap-and-gown ceremony at the end of these booze-fueled educational journeys and they won't do jack for your résumé. But we'll take a barroom over a classroom any day.

Michael Rietmulder writes about bars, beer and nightlife.