Spurting / geysering

Water erupting irregularly from the shower screen or group head — often with a gurgling or hissing sound — when starting a shot.

Why it matters — Typical of HX (heat-exchanger) machines that have been sitting idle. Too much steam has built up in the group's heat-exchanger loop, and the first pour vents it violently.

Good to know

• The fix is a cooling flush: pull water through the group for a few seconds before locking in the portafilter, until the flow is steady and steam-free.
• Constant spurting even with a flush suggests a deeper issue — check the gicleur and the brew thermosiphon path.