E61 OPV Pressure Setting

[killerloop]

Hi All,

Would like some expert opinion or input from your experience.

What is the recommended OPV reading or setup for E61 grouphead machines with a double boiler & rotary pump configuration ?

Should it be 8,9 or 10 at maximum on the pressure gauge during extraction?

I also did read somewhere that pressure at e.g. 10 bar at the gauge translates to approx 9 bar at the OPV - grouphead ?

Is that right?

Thanks for your reply,
Cheers

[sprezzatura]

E61 OPV Pressure Setting

Well, 9 bar is standard but we run espresso at different pressures for different roasts and grind particle size.

Your machine (if it's a lever actuator) can pre-infuse the puck and then deliver water at full pressure (9 bar) or lower pressure, say, 6.5 bar (if you choose to set the OPV/bypass that loose).

Gauges, unless newer, can be unreliable; best measure pressure with a portafiltre gauge at the group head.

[symphonie]

Well, 9 bar is standard but we run espresso at different pressures for different roasts and grind particle size.

Your machine (if it's a lever actuator) can pre-infuse the puck and then deliver water at full pressure (9 bar) or lower pressure, say, 6.5 bar (if you choose to set the OPV/bypass that loose).

Gauges, unless newer, can be unreliable; best measure pressure with a portafiltre gauge at the group head.

how do you ensure a portafilter gauge (unless its SCACE) is more accurate than the built in gauge . I mean they are usually of the similar quality.

[sprezzatura]

how do you ensure a portafilter gauge (unless its SCACE) is more accurate than the built in gauge . I mean they are usually of the similar quality.

I replace my p/f gauges every 2-3 months as running espresso tainted water and fines with its associated oils damages the gauge at the group head - so does the hot water. I have three different gauges including a German oil-filled precision gauge. Some machines have better quality gauges than others. I'm using a 20 bar oil filled gauge at the moment and it's very accurate.