Three days a week, you can find Sean Frederick behind the bar at Citizen, serving up some of Boston’s best cocktails. He’s a natural – hospitable, gracious and good with a shaker.

But years ago, Frederick describes his former self as “a frustrated bartender that never was.” He bartended throughout college in New Hampshire, eventually taking a lead role in helping set up a bar in Manchester.

“I learned to curb my enthusiasm pretty quickly,” says Frederick of his experience doing so. He wanted to be creative, but explains how the clientele up there just “weren’t used to a drink list that wasn’t 12 different flavored vodka martinis.”

“It was a good period where my enthusiasm and zealousness got tempered,” he says.

During that time, Frederick frequently made weekend trips down to Boston, where he got exposed to the cocktail scene here in town. “I was getting served by great bartenders and getting served awesome drinks,” says Frederick, and wondered why he didn’t have similar experience in New Hampshire.

Describing those bartenders as “humble,” “earnest,” and “hospitable,” Frederick was inspired to be a bartender of similar proportions, and decided to take the plunge and move to Boston. “The biggest thing that lured me to the job in Boston was great bartenders.”

For Frederick, bartending is something that can’t be learned.“As many old cocktail books I have on the shelves…No amount of reading is going to prepare me as an aspiring bartender than just jumping behind the bar.”

In terms of mentors, Frederick points to Jeff Grdinich of Drink, who was “doing the craft cocktail thing” in the White Mountains long before it was a thing, explains Frederick.

Additionally, Frederick says Eastern Standard is his favorite bar in the city. “That’s the place where I had my eureka moment.” He applauds Bob McCoy, the principle bartender at Eastern Standard, for the consistency he’s achieved over the past five years, “putting out good drinks at a mind-boggling volume.”

In 2010, Frederick jumped behind the bar at Citizen, loving the idea of working “in the shadow of Fenway Park.”

“It’s a long underserved neighborhood,” he says, describing Citizen as filling need for both “Esoteric, geeky, creative cocktails,” as well as a spot to grab a beer before or after a Sox game.

“I am happily a worker bee, part of a great team,” he says. “I am just another bartender at this bar.”

That’s the thing with Frederick – as much as I tried to steer the conversation back to him, he always brought it back to the entire team at Citizen, or his clientele in front of the bar.

“I love all of my days on the bar…a lot of that has to do with faces at the bar, sitting on the other side,” says Frederick, whose work often on the bar begins at 3 p.m. and lasts well past 3 a.m.

“I love the slow nights where you’re able to have long conversations with guests…just as much as I do serving people that I know I might never see again. The challenge is to try to give them the same level of hospitality.”