Amazon.comMac McCaughan tipped his hand about his goal for Portastatic early on with a cover of Brian Eno's "St. Elmo's Fire." His mostly solo side project is a vehicle to make his own version of Another Green World (or at least Here Come the Warm Jets) in his basement eight-track studio. Clarinet (courtesy of Lambchop's Jonathan Marx) and grand piano (ably played by McCaughan, who also tackles synthesizers, e-bowed guitar, vocals, and most other instruments) are the dominant sounds on Portastatic's third full-length effort, but this is no pseudo-classical avant-jazz minimalist post-rock wank-off. McCaughan displays the same unerring knack for hooks and inviting songcraft that he's always shown in Superchunk, only here he slows down the tempos, varies the instrumentation, and concerns himself more with the background (weird ambient soundscapes) than the foreground (verses, choruses, and such). Whether it's evidence of the notoriously prolific McCaughan easing up a bit, or he simply scraped up enough money to indulge himself this time, The Nature of Sap benefits from an attention to detail somewhat lacking in earlier, lower-fi outings. Jim Derogatis