When I visited this fall, the air was redolent with Montmorency pie cherries finishing their mash in a chilled steel tank. Shining copper stills, industrial macerators and barrels filled a huge, light-filled hangar on a former Naval base (the vodka is named for it: Hangar One). Within an hour the cherries had become eau de vie, dripping from a stainless steel pipe while Jörg Rupf, the founder, offered tastes to an impressively informed group of about 30 visitors.

Absinthe Verte, perfected by Lance Winters, Mr. Rupf’s distilling partner, is one of the handful of American absinthes on the market again after a centurylong drought. The spirit epitomizes the fervid scene in the Bay Area: it is at once classic, with a 19th-century aesthetic, and innovative — something that had not been available at all, much less in this highly cultured form.

The bar that best reflects this dichotomy is Bourbon & Branch. Styled a modern-day speakeasy, it is in a space in the seedy Tenderloin neighborhood that was once an actual speakeasy. A password (get it online with your reservation) is required to enter the den of wood, leather, distantly twinkling tinplate and oceans of brown liquors. Twenties jazz plays quietly, and guests are greeted with small glasses of champagne punch on linen coasters.

If it all seems a bit pompous — a reservation at a bar? — it works. Even on a Friday evening, Bourbon & Branch is an intimate setting for the contemplation of fine cocktails. It draws a diverse crowd of aficionados who are rewarded with exquisite drinks: the Sazerac is not too sweet, its rye bite balanced with a lemony nose. The 1794 (really a Boulevardier) is delicious. My Democrat, a concoction of peach and bourbon, was tasty but lacked heft. I sent it back and the bartender happily fixed the problem with a splash of bourbon.

The bar features a seasonal menu of what Brian Sheehy, one of the owners, calls “market fresh cocktails,” as well as two that change every day. Bourbon & Branch has become the nexus of a tight-knit community, with alumni opening bars and developing menus throughout the city. Last month, Mr. Sheehy and co-owners opened Cask, a store selling craft spirits and bartending paraphernalia.