Brew pressure reading of blind basket vs. Scace thermofilter

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F1
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#1: Post by F1 »

I have a SCACE I and when I use it on my HX E61 machine the machine's own pressure gauge reads 7.9bar. If I increase the brew pressure on the machine to 11bar with a blind portafilter it still reads 7.9 when using the SCACE I. Is that normal behavior? Shouldn't the increase in pressure also be reflected when using the SCACE I?

NOTE. I run my HX E61 at 11bar(set with blind disc) because I believe(just a guess) that is about 9ish bar at the puck. The reason I got to that conclusion is because my other E61(Profitec 700) which is set at 9bar makes the same coffee taste/look/smell the same on both machines. If I go lower(less than 10bar) on my HX E61 then the shots come out watery/thin/light color/bitter. Grinding finer doesn't help in this case.

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keno
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#2: Post by keno »

Search function is your friend: Brewtus brew pressure problems / Scace thermofilter 2 instruction request.

The Scace I measures only temperature at the puck, so the pressures you are quoting reflect the pressure gauge on the machine. My understanding of the Scace device is that it simulates the flow of the puck to get a more accurate measure. It's not a blind filter. So increasing the pump pressure has no effect at the group head because the flow from the Scace sets an effective upper limit on the pump pressure.

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#3: Post by F1 (original poster) »

Search found 626 matches: Scace Pressure

Thx for an answer though. :|

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HB
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#4: Post by HB »

F1 wrote:If I increase the brew pressure on the machine to 11bar with a blind portafilter it still reads 7.9 when using the SCACE I. Is that normal behavior? Shouldn't the increase in pressure also be reflected when using the SCACE I?
It sounds like the blind reading is the over-pressure valve setpoint, not the setpoint of the rotary pump. This happens if the rotary pump valve has a standard bypass valve instead of a balanced bypass valve. Are you adjusting the pressure on the pump? Some people mistakenly adjust the over-pressure valve like one would for an espresso machine with a vibratory pump, not realizing the rotary pump has its own pressure adjustment screw.

Related topics for your reference:
Dan Kehn

F1 (original poster)
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#5: Post by F1 (original poster) »

The HX has a vibe pump. I forgot to mention that. The machine is a Rocket giotto PPV2 that has the regular OPV valve which is set at 12bar and a second slightly smaller OPV(11bar) valve with a close/open ball knob.

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erics
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#6: Post by erics »

The HX has a vibe pump. I forgot to mention that. The machine is a Rocket giotto PPV2 that has the regular OPV valve which is set at 12bar and a second slightly smaller OPV(11bar) valve with a close/open ball knob.
The thermofilter designed by Greg S. is intended to flow the TOTAL amount of water used in a typical shot at 9.0 bar. This has been debated over the years . . . link references are beyond me at this point but the design flow was determined by some very knowledgeable folks. The total flow for an E-61 machine would be greater than that of LM (or their equivalents) machines.

See section 4.3 of this: http://www.worldbaristachampionship.com ... chines.pdf

For your machine, close the ball valve and adjust the OPV such that the machine's gage reads 9.0 bar with the thermofilter in place. Now open the ball valve for normal operation.
Skål,

Eric S.
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E-mail: erics at rcn dot com

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#7: Post by F1 (original poster) »

erics wrote:The thermofilter designed by Greg S. is intended to flow the TOTAL amount of water used in a typical shot at 9.0 bar. This has been debated over the years . . . link references are beyond me at this point but the design flow was determined by some very knowledgeable folks.

For your machine, close the ball valve and adjust the OPV such that the machine's gage reads 9.0 bar with the thermofilter in place. Now open the ball valve for normal operation.
If I do that then I cant adjust the ball valve any higher than 9bar. At 9bar the shots come out like if they were made at 6-7bar on my Profitec 700. The shots come out watery/thin/bitter (underextracted). The ball valve OPV in my HX machine is a new one by Rocket. It is now adjustable just like the regular OPV valve. It even looks almost like the regular OPV valve. Since I have to set the ball valve OPV at 11bar, then I set the regular OPV at 12bar to have 1bar headroom.

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#8: Post by F1 (original poster) »

The old ball valve OPV looked like this circled in red.


The new one looks like this.

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erics
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#9: Post by erics »

In the picture you posted, item 1 is a ball valve, item 2 is what I have previously termed a "secondary" pre-infusion valve, item 3 is a check valve, and item 4 is the normal OPV valve.

Since your configuration (particularly the adjustability of item 2) is different than the original, I would suggest you contact Rocket and/or the dealer from whom you purchased the "new" item 2 for instructions. What I wrote is applicable to the former configuration.
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Eric S.
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#10: Post by F1 (original poster) »

So going back to the original question. I believe the answer was that since the SCACE is made to simulate the resistance of a coffee puck then I can't influence the reading on the espresso machine's brew pressure gauge. Correct?

With SCACE I in place the pressure reads 7.9bar
With Blind Filter it reads 11bar
With coffee it reads 11bar

I just don't know/think that the temperature reading I am getting with the SCACE I is representative of the temperature when using coffee due to 7.9bar vs 11bar. Maybe the difference is not significant and I am worrying about nothing . I don't know.

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