For those unfamiliar with the mythology of Portland experimental rock troupe Grails, Black Tar is the catchall name for the various limited-edition releases that the band cooks up between albums. This compilation grabs the most recent of those—a picture disc EP issued by Important Records and a split LP with Finnish psych freaks Pharaoh Overlord—appending three new songs. The beauty of a collection like this is that it isn't a cobbled-together, odds-'n'-sods grouping of old, random recordings. These 12 tracks feel like an extension of the world that Grails was exploring on its most recent LP, 2011's Deep Politics. The same sinking feeling carries over here, cut through with some wicked strands of light (the Morricone-esque "A Mansion Has Many Rooms," the sly jabs at organized religion on the two "New Drug" tracks). Being a compilation, though, Black Tar doesn't cohere like a bona fide album would. The transitions from track to track don't feel as smooth. The introspective "Invitation to Ruin" doesn't fit so comfortably between the brasher, harder-edged "Self-Hypnosis" and "Wake Up Drill II." The pieces work well individually, but strung together as they are here, they make for a misshapen picture. 

HEAR IT: The album is out Tuesday, Oct. 15.