A couple of months ago, Dua Lipa sparked a flurry of interest on social media when she posted a video of herself drinking a ‘Dirty Diet Coke’, laced with pickle juice and the brine from a jar of jalapeño peppers. On the face of it, that might sound a pretty weird thing to do, revolting even, but what the singer was doing is actually nothing new. Her drink can be traced back to a tradition created by an Irish bartender in New York more than a century ago.