Reading the pressure gauge on an espresso machine
How to read an espresso machine pressure gauge
This site explains what the needle on an espresso machine gauge is measuring and where. It looks at the units, the marked zones and what the needle does during a shot. It also covers why a reading can look high or low.
All the gauge notes
What an Espresso Machine Pressure Gauge ShowsWhat the needle on an espresso machine gauge is actually measuring, how a dial gauge works inside, and what the numbers on the face mean.
Bar, PSI and the Colored Zones on the DialHow to read the units on an espresso machine gauge, what bar and psi mean, and how marked zones on the dial relate to the needle during a shot.
Pump Pressure Versus Boiler Pressure GaugesWhy some espresso machines show brew pressure, others show steam boiler pressure, and some show both, and what each needle is really telling you.
Reading the Needle During a ShotWhat a brew pressure needle does from the first second of a shot to the last, which part of the shot to watch, and what a sudden drop can mean.
Why the Gauge Reads High or LowWhat can push an espresso machine gauge needle above or below the marked zone, from grind and pump wear to mains pressure and the gauge itself.
How the Gauge Shows Pre-InfusionWhy the needle on some espresso machines rises slowly at the start of a shot, what pre-infusion is, and what one maker's manual says the zone means.
The Gauge and the Over-Pressure ValveWhat the over-pressure valve (OPV) on an espresso machine is, how it relates to what the gauge shows, and why adjusting it is a job for the maker.