Jackson Cannon’s favorite bar tool is a Hawthorne strainer. The tool is distinguished by its springy wire coil, which fits snugly into the top of a mixing glass. He likens it to a saxophone: It was around long before the world went electric, yet it’s still a very specific, useful, modern instrument.

Kayana Szymczak for the Boston Globe

Guests at the Hawthorne sit in a small lounge area.

“It’s 19th-century technology, and we still use it,’’ says Cannon, a co-owner of the Hawthorne, the new bar in the Commonwealth Hotel’s semi-subterranean space, formerly occupied by the Foundation Lounge. It opened this week.

That sense of timelessness runs through every aspect of the bar. It’s first evident in the books on a shelf in the hostess stand: “The Iliad,’’ “The Orwell Reader,’’ “The Dimensions of Robert Frost.’’ It continues through the design. The husband-and-wife team of Stephen and Allison Sheffield of Sheffield Interiors created a space that suggests a sprawling living room, what with several arrangements of couches and armchairs, scattered ceramic vases and piles of books, handsome walnut bureaus, and elegant modular tray tables.

Kayana Szymczak for the Boston Globe

The bar is located inside the Commonwealth Hotel.

Predictably, that timelessness is evident in the drinks list, a healthy mix of old-school standards and contemporary smash hits. But they’re not precious about vintage craft cocktails, obscure ingredients, or retro glassware, trends that have been snowballing in the past few years, (just try to find a new restaurant that doesn’t bill its drinks as “classic’’). The Cocktail-with-a-capital-C will not sit on a pedestal here, says Cannon, who’s also bar director for Eastern Standard and Island Creek Oyster Bar. (Both are also located in the Commonwealth.)

“We really want a place that feels natural and comfortable,’’ he says, searching for a better word to express the thrilling familiarity of nestling into your favorite plush chair on a cold night with a companion and a drink.

“Sure, you can decant a red wine or geek out over cocktails at home,’’ he says, “but there’s a divide between a domestic social event and a commercial bar. We’re talking about overcoming that divide.’’