Pump pressure vs brew pressure

Two different pressures inside an espresso machine. Pump pressure is what the pump itself produces — typically capped at 9–12 bar by the OPV. Brew pressure is what reaches the puck — affected by gicleurs, restrictors, and flow control devices.

Why it matters — These are not always the same. A pump set at 11 bar but with a small gicleur can deliver 9 bar brew pressure during the shot. Most prosumer machines display brew pressure on the front panel — that's the one that matters for extraction.

Good to know

• Adjust the OPV (pump pressure) to control the maximum; control brew pressure with restrictors, flow control devices, or pre-infusion settings.
• If your shot pressure peaks above 10 bar at the puck, channelling and harshness are likely outcomes.