Simmer Down is a new cocktail bar inside a former Wilmington bank vault

In the late 19th century, bankers at the Security Trust & Safe Deposit Co. in downtown Wilmington stashed their riches in the basement vault.

As of last week, the so-called money room offers an entirely new experience: a cocktail bar called Simmer Down that’s part of the Frank Furness-designed building’s current use, a hotel called The Quoin at Sixth and Lower Market Streets operated by the Method Co.

On the street level is a new restaurant, also called The Quoin, adding to a new buzzy dining scene in Delaware. The hotel also has a lobby lounge and a rooftop bar and lounge. (Method’s Philadelphia restaurant properties include Wm. Mulherin’s Sons and Hiroki in Fishtown, and a Mulherin’s opening this year in East Market.)

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Simmer Down’s cocktails were developed by Method’s creative beverage directors Jeremy Oertel and Natasha David, whose past include New York’s Death & Co and Maison Premiere.

Their original cocktails include the White Rabbit (mescal, blanco tequila, red bitter, blanc vermouth, jalapeño, and carrot eau de vie) and the Deep Dish (bourbon, Jamaica rum, mace, Castilian, and pecan bitters). Figure on $18 for a classic cocktail, $20 for originals.

Philadelphia’s Stokes Architecture + Design focused on the archtecture, while Method Studios did the design. There is a 13-seat green marble topped bar in the center and a hand-painted, surreal mural by Philadelphia-based artist Reverend Michael Alan. A rose-colored mohair banquette, trimmed in fringe and set amid bookshelves and cabinetry, lines the perimeter of the room. At the back of the room, a pair of velvet sofas sit in front of a fireplace with a honed white Carrara marble surround.

Randall Cook, Method’s cofounder, said he was inspired by his days at the University of Pennsylvania’s fine-arts library, which has a similar aesthetic.

“When we saw the [bank] building, we fell in love with it for a boutique hotel, but as we were exploring the building, we realized the basement had these barrel-vaulted ceilings that were brick but had been painted white,” Cook said. “It’s super rare to find a basement that has a barrel-vaulted ceiling. I said immediately that this would be an outstanding place to put a cocktail lounge. To me, it was like the ultimate thing — to allow people to have some place to go after dinner for a nightcap in a very kind of dark and moody atmosphere.” The paint was stripped off to reveal a warm red.

It’s open from 6 to 11 p.m. Tuesday to Thursday, 6 p.m. to midnight Friday and Saturday, and 5 to 10 p.m. Sunday. No reservations.