As with their prior records, all four band members contributed to the songwriting of "Percolater". Reynolds' "MO. 63" describes driving on U.S. Route 63 through the band's new surroundings: "Fat, farting Guernseys chew their cuds at me / Missouri 63 / Big Buford lawman ten miles from Moberly / Says 'you got a taillight on the right side that don't work properly. The album includes three instrumental tracks—"Charligan", "Birds", and "Gnugear (Hot)"—out of five in the band's whole catalog; authorship of these tracks is not listed in the album's credits.