Get out the plastic painter sheets and the kitty litter. Check local building codes and keep a mop, fire extinguisher and disinfectant handy. The annual Bratwurst performance at Homegrown is always a bit more than an aural experience. Tyler Scouton acts as ringmaster for an industrial noise circus while Jason Ratajek and Benny Tryon move from guitars to power tools to kitchen blenders with equal amounts of decibels and debris. Brennan Atchison’s drum work attempts to keep the spectacle in time, but in the end Bratwurst’s musical contributions are ones of welcome discomfort and Grand Guignol.