When to replace your group head gasket (and how)

This guide explains when and how to replace the group head gasket on a home espresso machine — covering the signs of wear, the gasket size by machine, and the swap procedure. The article walks through the three telltale signs: a portafilter that's harder to lock in than it used to be, a fine trickle of water around the edge during the shot, and a portafilter that no longer locks home at 6 o'clock (it's drifting because the gasket has compressed). It explains the gasket size reference by machine: 8mm or 8.5mm E61 gaskets for Rocket, ECM, Profitec, Bezzera, most Lelit; the LM-specific profile for La Marzocco; the Breville/Sage profiles for those machines; and the older sizes for vintage gear. The article covers the OEM-rubber-vs-silicone choice in detail. Coffee Parts house silicone gaskets last roughly twice as long as OEM rubber, but the bigger argument for silicone is the daily feel — a fresh silicone gasket gives the portafilter a smooth, confident lock-in that compounds across hundreds of pulls. The swap procedure is covered with photo callouts (when published), including the screwdriver-poke technique for removing an old gasket without scratching the group, and the conditioning step for a new gasket. Cross-sells include the Coffee Parts silicone gasket range, the relevant group brushes for the maintenance cycle that goes with a gasket replacement, and Cafetto cleaning chemistry for the broader weekly routine.