It is your machine and your gauge and if the results work for you that is what counts. I just have never heard about a vibe pump on an espresso machine that produced 19 bar of pressure, hey it is possible I am completely wrong and your machine has one, lol. If you care I would check on the pump you have and what it is rated at, if it is not 19 bar then you might want rethink how accurate your gauge reading are.
diggi Senior Member Joined: 28 Nov 2011 Posts: 382 Location: Halifax, NS Expertise: I love coffee
Espresso: Spaz vivaldi S1 V2 Grinder: B Vario, OE LIDO Drip: Chemex, Espro Press,... Roaster: Poppery I
Posted Tue Apr 10, 2012, 2:10pm Subject: Re: Why do espresso machines come with chronically high OPV settings?
germantownrob Said:
I can build a shot and get 9 bars resistance even if the pump is putting out 16bar of pressure but any mistake in prep will result in a problem that will lead to over and under extraction issues.
I don't really understand where this is coming from. You have a machine that is set properly. You seem to be downplaying the importance of setting the OPV, which is in fact what it was built for. You can change the pressure delivered from your 'dumb' pump without regulation; to set it to the 'standard' and optimize the pressure delivered. I don't know why anyone should knowingly use a machine that was deliberately set to the wrong standard (for pods) and not make the appropriate adjustment. Why not set your pressure higher?
I know this has been argued to the nth degree, but my take is that the OPV is downplayed by many who have machines with properly set OPV's. Those who have one set too high (on purpose by manufacturer) go to extremes to bring it down to the proper setting. And shouldn't they?
JDHarding Senior Member Joined: 31 Aug 2007 Posts: 1,099 Location: WA, USA Expertise: I love coffee
Espresso: Ascaso Steel Pro PID Grinder: Nuova Simonelli MDX,... Vac Pot: None Drip: Hario v60 Roaster: Behmor, Fresh Roast
Posted Tue Apr 10, 2012, 2:13pm Subject: Re: Why do espresso machines come with chronically high OPV settings?
germantownrob Said:
It is your machine and your gauge and if the results work for you that is what counts. I just have never heard about a vibe pump on an espresso machine that produced 19 bar of pressure, hey it is possible I am completely wrong and your machine has one, lol. If you care I would check on the pump you have and what it is rated at, if it is not 19 bar then you might want rethink how accurate your gauge reading are.
I actually don't know what the original rating was. It could be 15-16 bar, I don't remember. I saw on a website that was selling the same machine that it was 19-bar, but I doubt it actually was 19-bar.
A lot of trusted authorities believed the earth was flat and was the center of the universe. The general consensus was to reelect George W. Bush. I don't blindly trust things just because a lot of people agree that it must be true - particularly when direct experimentation gives me different results ...
On my machines 11 bars against a blind is too high but 9.5-10 is right ... I'm sure there are other machines that trusted posters own that give the right pressure when set at 11 against a blind basket. I've tested with different pumps (higher flowing and lower flowing) and different OPV valves (large valves, small valves, valves with very stiff springs, valves with softer springs) ... they all behave very differently in regards to the blind vs flow when setting the pressure.
Posted Tue Apr 10, 2012, 7:23pm Subject: Re: Why do espresso machines come with chronically high OPV settings?
AndyPanda Said:
...On my machines 11 bars against a blind is too high but 9.5-10 is right ... I'm sure there are other machines that trusted posters own that give the right pressure when set at 11 against a blind basket. I've tested with different pumps (higher flowing and lower flowing) and different OPV valves (large valves, small valves, valves with very stiff springs, valves with softer springs) ... they all behave very differently in regards to the blind vs flow when setting the pressure.
jwoodyu Senior Member Joined: 31 Dec 2010 Posts: 704 Location: Michigan Expertise: I love coffee
Espresso: Allex Duetto II Grinder: Mazzer Major Roaster: Poppery
Posted Tue Apr 10, 2012, 8:04pm Subject: Re: Why do espresso machines come with chronically high OPV settings?
I run Duetto (rotary) at a hair more than 9 on the gauge. It does not matter if in empty basket, puck, or blind it always the same. To me not only are shots themselves better at 9 vs 9.5 or more the aftertaste is better, but may e it's just me.
You know those people that want to tell you how to raise your kids but have none of their own? That is how i feel when someone with a kitchen appliance tells me how the merits or dis-merits of my machine or how to use it.
germantownrob Senior Member Joined: 2 Dec 2007 Posts: 2,018 Location: Philadelphia Expertise: I love coffee
Espresso: Duetto 3, A Dead Oscar Grinder: Vario-W, Preciso w/Esatto,... Drip: Brazen Roaster: Diedrich IR-1, HT B
Posted Tue Apr 10, 2012, 8:57pm Subject: Re: Why do espresso machines come with chronically high OPV settings?
AndyPanda Said:
A lot of trusted authorities believed the earth was flat and was the center of the universe. The general consensus was to reelect George W. Bush. I don't blindly trust things just because a lot of people agree that it must be true - particularly when direct experimentation gives me different results ...
On my machines 11 bars against a blind is too high but 9.5-10 is right ... I'm sure there are other machines that trusted posters own that give the right pressure when set at 11 against a blind basket. I've tested with different pumps (higher flowing and lower flowing) and different OPV valves (large valves, small valves, valves with very stiff springs, valves with softer springs) ... they all behave very differently in regards to the blind vs flow when setting the pressure.
germantownrob Senior Member Joined: 2 Dec 2007 Posts: 2,018 Location: Philadelphia Expertise: I love coffee
Espresso: Duetto 3, A Dead Oscar Grinder: Vario-W, Preciso w/Esatto,... Drip: Brazen Roaster: Diedrich IR-1, HT B
Posted Tue Apr 10, 2012, 9:29pm Subject: Re: Why do espresso machines come with chronically high OPV settings?
diggi Said:
I don't really understand where this is coming from. You have a machine that is set properly. You seem to be downplaying the importance of setting the OPV, which is in fact what it was built for. You can change the pressure delivered from your 'dumb' pump without regulation; to set it to the 'standard' and optimize the pressure delivered. I don't know why anyone should knowingly use a machine that was deliberately set to the wrong standard (for pods) and not make the appropriate adjustment. Why not set your pressure higher?
I know this has been argued to the nth degree, but my take is that the OPV is downplayed by many who have machines with properly set OPV's. Those who have one set too high (on purpose by manufacturer) go to extremes to bring it down to the proper setting. And shouldn't they?
Lol, actually the Oscar has a very crappy opv, and other very highly regarded manufactures use no opv. I am not down playing this, I am questioning this . As far as taste goes for high pressure the consensus in this thread is very inconsistent when compared to lever machines and their low pressure delivery. As for showing baristas flaws in shot distribution high pressure will expose them and that is consistent.
Btw my blind pressure is at 12 bar, anything below diverts to much water and can effect shot temp during a pull. So I can have 9 bar but I loose thermal stability to achieve that using Oscars opv.
Bad time to bring up the subject of pressure profiling?
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