A portafilter that feels seized — won't turn to lock in, or won't turn to release after brewing — is usually one of two things: pressure still trapped in the group head, or physical binding from grounds buildup.
01Residual pressure (won't unlock after brewing)
If it's stuck after a shot, residual pressure in the group head is the most common cause. Wait 20-30 seconds after the pour finishes before attempting to remove it — forcing it while pressurized is both harder and can damage the locking tabs.
02Coffee grounds buildup on the ramps
Dried coffee residue on the group head's locking ramps creates friction that makes the portafilter feel stuck or gritty when turning. Clean the ramps and the underside of the group head with a damp cloth or brush, particularly if you notice visible buildup.
03Won't turn to lock in (not stuck, just resistant)
If it's difficult to lock in rather than stuck after brewing, an overfilled basket is the likely cause — the puck is pressing against the shower screen before the tabs can fully engage. Check your dose against the basket's rated capacity and use the included Razor tool to level it.