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Date: 18 Jul 2006 20:37:49
From: Elli Geek
Subject: Different pump pressure on machine guage versus portafilter guage
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I just picked up a commercial one group (e61 style) and am trying to
set the pump (rotary) pressure correctly. My portafilter guage says
9.25 bar (though it does start to climb as this is dead head pressure).
The guage on the machine reads about 1 bar higher at 10.25 bar. I have
no idea which one is accurate...any suggestions on which to follow, or
ways to test? Thanks!
-Mark
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Date: 19 Jul 2006 05:22:03
From: Barry Jarrett
Subject: Re: Different pump pressure on machine guage versus portafilter guage
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On 18 Jul 2006 20:37:49 -0700, "Elli Geek" <markpwalters@gmail.com >
wrote:
>I just picked up a commercial one group (e61 style) and am trying to
>set the pump (rotary) pressure correctly. My portafilter guage says
>9.25 bar (though it does start to climb as this is dead head pressure).
>The guage on the machine reads about 1 bar higher at 10.25 bar. I have
>no idea which one is accurate...any suggestions on which to follow, or
>ways to test? Thanks!
use the pf gauge.
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Date: 18 Jul 2006 22:55:00
From: Ken Fox
Subject: Re: Different pump pressure on machine guage versus portafilter guage
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"Elli Geek" <markpwalters@gmail.com > wrote in message
news:1153280269.008108.271510@i3g2000cwc.googlegroups.com...
>I just picked up a commercial one group (e61 style) and am trying to
> set the pump (rotary) pressure correctly. My portafilter guage says
> 9.25 bar (though it does start to climb as this is dead head pressure).
> The guage on the machine reads about 1 bar higher at 10.25 bar. I have
> no idea which one is accurate...any suggestions on which to follow, or
> ways to test? Thanks!
>
> -Mark
>
Michael Teahan told me once that a properly working front panel pressure
gauge will read about a bar higher than one will get with a PF manometer.
Since you are only really interested in what pressure the puck sees, I would
use the PF Manometer reading as representative of what other people talk
about, when they discuss extraction pressure. For all practical purposes
there is not going to be a huge amount of difference in the espresso you get
extracted at 10.25 bar vs. 9.25 bar. In any event, 9.25bar measured at the
PF manometer, is close enough to 9bar that I would not adjust it further as
you are unlikely to get a result that is appreciably "better."
ken
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Date: 19 Jul 2006 04:47:16
From: Paul Monaghan
Subject: Re: Different pump pressure on machine guage versus portafilter guage
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Where do the needles on both gauges rest at presumably zero pressure?
On 18 Jul 2006 20:37:49 -0700, "Elli Geek" <markpwalters@gmail.com >
wrote:
>I just picked up a commercial one group (e61 style) and am trying to
>set the pump (rotary) pressure correctly. My portafilter guage says
>9.25 bar (though it does start to climb as this is dead head pressure).
>The guage on the machine reads about 1 bar higher at 10.25 bar. I have
>no idea which one is accurate...any suggestions on which to follow, or
>ways to test? Thanks!
>
>-Mark
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Date: 19 Jul 2006 20:49:58
From: Dan Bollinger
Subject: Re: Different pump pressure on machine guage versus portafilter guage
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Keep in mind that the precision of gauges used on consumer machines are likely
in the ±10% range. Dan
>I just picked up a commercial one group (e61 style) and am trying to
> set the pump (rotary) pressure correctly. My portafilter guage says
> 9.25 bar (though it does start to climb as this is dead head pressure).
> The guage on the machine reads about 1 bar higher at 10.25 bar. I have
> no idea which one is accurate...any suggestions on which to follow, or
> ways to test? Thanks!
>
> -Mark
>
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Date: 19 Jul 2006 20:51:35
From: Dan Bollinger
Subject: Re: Different pump pressure on machine guage versus portafilter guage
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> Keep in mind that the precision of gauges used on consumer machines are likely
> in the ±10% range. Dan
Sorry, I meant to say 'accuracy', not precision.
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