Bastro was the more prominent of guitarist David Grubbs' two immediate post-Squirrel Bait projects (the concurrently running Bitch Magnet being the other). Grubbs originally joined the Louisville, KY-based Squirrel Bait while still in high school, and was actually one of the oldest members of the group; when he and bassist Clark Johnson left for college, it effectively spelled the end of the band after two important releases. Grubbs went to Georgetown University in Washington, D.C., and formed an early version of Bastro in 1987 with bassist Dan Treado, who soon left. Even though Clark Johnson had gone to Chicago, he and Grubbs reteamed as the new core of Bastro, and pursued a more twisted and abrasive style of post-hardcore punk than their former band. Backed by a drum machine, they issued a six-song EP, Rode Hard & Put Up Wet, on the Homestead label in 1988. They subsequently played some tour dates with My Dad Is Dead, whose drummer at the time was Oberlin College percussion major John McEntire. McEntire wound up joining Bastro full-time for their LP debut, 1989's Bastro Diablo Guapo, which drew comparisons to the blistering extremity of Steve Albini and the precision and shifting dynamics of another Squirrel Bait offshoot, Slint. Their second full-length, 1990's Sing the Troubled Beast, found the group straining against their established blueprint to follow a relatively subtle and melodic path. Bassist Johnson subsequently left the group and was replaced by Bundy K. Brown; meanwhile, Grubbs relocated to Chicago to attend graduate school. Feeling limited by the extremity of their power-trio format and afraid of stagnating, Bastro tried to push into more atmospheric territory, and wound up deciding to retire the name altogether and continue as a completely different project, dubbed Gastr del Sol. Brown and McEntire appeared on Gastr del Sol's 1993 debut, The Serpentine Similar, after which the group became a vehicle for Grubbs' collaboration with Jim O'Rourke, as well as a touchstone of the post-rock movement. Brown and McEntire subsequently became charter members of the even more seminal post-rock outfit Tortoise.