Pressure Gauge

An analogue or digital instrument that displays pressure — either steam boiler pressure or brew pressure at the group. Most prosumer machines have both gauges on the front panel.

Why it matters — Pressure gauges are the most useful diagnostic on an espresso machine. They tell you when something is wrong (over-pressure, under-pressure, drift) and when something is right (stable 9 bar mid-shot, steady 1.2 bar boiler).

Good to know

• The middle of the shot is the reading that matters most for brew pressure. First-second and last-second readings always vary from steady-state.
• Boiler gauges should sit stable at the pstat or PID set point — drift or swing indicates a controller fault.