Following soon after the critically praised Black Tar Prophecies collection on Important Records, Portland, Oregon's Grails return with their first proper studio album since 2004 release of Redlight. Burning Off Impurities - their debut for Temporary Residence Ltd. - makes good on the promise of those past releases in delivering an album that not only thursts the group to new heights, but also pushes the instrumental rock genre forward for the first time in nearly a decade. An increased interest in psychedelic, ambient and world musics is most likely to blame for Grails' exploration of the lesser-traveled paths of modern music. In addition, their eclectic range of collaborative endeavors - guitarist Zak Riles is also in M. Ward band, while drummer Emil Amos has moonlighted as Jandek's drummer - has introduced an element of improvisation and reinterpretation of ideas that is both brilliant and earnest. Like Black Tar Prophecies, Burning Off Impurities was produced by Grails, with production assistance by Jeff Saltzman and Steven Wray Lobdell (of avant-garde legends, Faust). Influenced in equal parts by Ash Ra Tempel, Erkin Koray, Popol Vuh, Black Sabbath, Led Zeppelin, and dozens others, this is very likely the closest Grails will ever get to making a classic rock record; the kind of sprawling masterpiece that you savor for years before passing it on to your younger brother so he can repeat the process.