A cocktail shaker and an artisanal mixologist? So 2011. This year, bars en masse began offering premixed drinks on demand. Mike Isabella, who put prosecco on tap at Graffiato, added margaritas to his draft lines at his Georgetown outpost, Bandolero. El Chucho in Columbia Heights followed suit, and Jack Rose Saloon, Policy, The Passenger, and even Del Frisco’s Grille also serve liquor-based drinks on tap. And there were bottled options, too: Elisir tried them when it first opened, and The Coupe, which opened this fall in Columbia Heights, offers three varieties. (Our favorite: the $11 “Georgia Comforter” with Filibuster bourbon, rosemary smoked maple syrup, and peach bitters.) Logistics were the mother of invention: Coupe Beverage Director David Fritzler says the bottled drinks help serve a high volume of craft cocktails in a big space. The cocktails are made in several gallon batches daily. “You can really tweak the drink that way,” Fritzler says. “If you change a quarter ounce in an individual cocktail, it’s pretty dramatic. So, you can really make kind of subtle changes to batches.”