Thanks to members’ involvement in 90s stoner rock pioneers Dozer, Swedish rock quintet Greenleaf still gets the words “side project* attached to any paragraphs in which its name comes up. Which seems unfair, given that Nest of Vipers is its fourth LP in a decade, which is a pretty good track record in the ‘aughts. Regardless, Nest of Vipers refines the band’s timeless classic rock sound, giving it just enough polish to stand out from similar retro rock acts, but not enough to diminish the raw performances. Unlike most of its contemporaries, Greenleaf’s modus operandi draws more from Deep Purple than Black Sabbath, eschewing sluggish tempos, devilish tritones and haunted atmosphere in favor of stripped-down riffage, macho energy and forthright rocking. While “At the Helm” and the title cut definitely fall into the psychedelic end of the hard rock pool (and very comfortably at that), “Jack Staff,” “Sunken Ships” and “Dreamcatcher” waste no time blasting out the proto-metal hooks and four-on-the-floor rhythms. Kudos also to singer Fredrik Nordin, whose soulful pipes give Greenleaf extra oomph, and a songwriting standard that assume intelligence on the part of the listener. For fans of 70s retro metal, Nest of Vipers gets gold stars all around.