THE EVOLUTION OF Korpiklaani has been so slight, we barely clocked it was taking place. The Finns’ debut, 2003’s Spirit Of The Forest, earned them a reputation as perennial boozers, known for putting on shows that resembled a folk metal Oktoberfest. For years, subsequent albums suggested the band had little inclination to deviate stylistically from that template, while songs like Beer Beer and Vodka insinuated they were content to operate on the outskirts of gimmickery.