Brew pressure

What the gauge should read

Unusually, La Marzocco puts brew pressure in the owner's manual, with no warning to call a technician. The pump is set to 9 bar at the factory, and the brew gauge should read 8 to 10 bar while brewing. The manual says never go above 10 bar.

The screw is on the rotary pump, under the top tray and the lower tray beneath it. One owner reports a 2022 machine that left the factory at 12 bar, which a technician reset to 9.

Do not confuse it with the expansion valve, which holds the group at 12 bar while it heats and is not adjusted.

Adjust the pump screw

The manual's steps. The machine is on and hot while you do this.

1. Lift off the top tray (the cup-warmer grid) and the lower tray under it.
2. Lock in a portafilter with coffee in it, as for a shot.
3. Start brewing with the paddle.
4. Turn the pump's adjustment screw: clockwise raises the pressure, anticlockwise lowers it.
5. Read the brew gauge as it brews, and never go above 10 bar.
6. Stop the shot and refit both trays.

La Marzocco Linea Micra: every job