TroyR wrote:Thanks, $30 ish CAD at ColeParmer.ca for the gauge.

Actually, I have yet to convince myself that dialing down my OPV from 13 bar to anything else is a good idea (or at least that it will make a difference to most of my shots). I am of the mind that a good shot will naturally create a system pressure in the 8 or 9 bar range and that the 13 bar OPV is a max limit for the system to allow flow and prevent damage in the case of a choked system.
Anybody want to support that or change my mind?


Regards,
Troy

My experience is that much over 9 bars at the group makes the taste quite sharp and bitter, regardless of the pressure profile or pre-infusion scheme. I'm fortunate to have an electronically controlled pressure system that allows me to program brew pressures, profiles and pre-infusion while holding other variables constant. It is also by no means true that the system pressure will self-regulate to 9 bars if the flow is correct thru the cake. Pressure thru the cake is dependent on the upstream pressure established by the pump, the pump type, pressure relief valve configuration, and the configuration of the flow path between the pump and the group (diameter, length, gicleurs, solenoid location and type, etc.). The right way to do the measurement is to do it under flowing conditions. It's the only way you're gonna make any meaningful correlation to taste that can be transferred to other machinery. The 13 bar number that you quote may work as a static pressure measurement for a machine that uses a vibe pump with a long-stroke pressure relief valve, but it will not work at all for a machine with a short-stroke pressure relief valve scheme, or rotary pump. Best to do the measurement properly so that there is no performance variation due to flow path variability.

-Greg

indeed with some water running it give a more accurate reading..


here is one I made with some fittings of an old gaggia.

Here is what mine looks like:

I need to build one of these to test my Silvia. Does anyone know if the spout on the original portafilter that came with with Silvia can be wrenched off so I can use it. I have tried it and it doesn't budge. I have a nice LM but I would rather not mess with it.

My other option is to just buy the e61 portafilter from chris's that comes with the pressure gauge and modify it to allow flow, not just blind.

Anyone in Chicago want to share

gj91 wrote:I have tried it and it doesn't budge.

I assure you it does come off. Try clamping the spout in a padded vice and pulling the handle really hard.

Woo-hoo! A screwdriver in the spout and a little more persuasion and it came off.

Now off to source a gauge.

If building a simple one this may help..
http://coffeegeek.com/forums/espresso/machines/422639

I have looked at a ton of these now between HB and Coffeegeek. I am going to give a non-liquid gauge a shot. I am going the flow through route. Otherwise I am going to get one of the liquid filled ones. I just don't see the liquid filled ones at local hardware stores. I am going to try HD and Lowes.

I first need to test my Silvia then I will probably have to get the new OPV valve if I need to adjust. It seems that 9 bar without the flow is a good target, that means it's a little less when there is actually flow.

Given my own experience, which involved visiting every hardware and plumbing supply in the area, I'd suggest you just go online and buy a liquid-filled one that way. I spent a couple of days going into every store in the area and asking every clerk and having to 'splain every time why the ones they had (not liquid filled) were not appropriate to my needs. If your time is valuable to you, just cut to the chase and source one online.

Susan

Given my own experience, which involved visiting every hardware and plumbing supply in the area, I'd suggest you just go online and buy a liquid-filled one that way. I spent a couple of days going into every store in the area and asking every clerk and having to 'splain every time why the ones they had (not liquid filled) were not appropriate to my needs. If your time is valuable to you, just cut to the chase and source one online.

Susan

Susan,

every, but EVERY espresso machine with gauges (boiler pressure gauge or pump gauge), have dry gauges..
I, personally try few dry gauges for the boiler and pump pressure.. and even the cheap $2-3 from ebay work no problem..
I can tell you that FOR SURE dry gauges work..

So I have heard you posit many times, but for me and for everyone else I have discussed this issue with, a dry gauge will only work if it has had a "snubber" added to it.

I found that sourcing a liquid gauge was easier than sourcing a snubber.

Susan

SJM wrote:Given my own experience, which involved visiting every hardware and plumbing supply in the area, I'd suggest you just go online and buy a liquid-filled one that way. I spent a couple of days going into every store in the area and asking every clerk and having to 'splain every time why the ones they had (not liquid filled) were not appropriate to my needs. If your time is valuable to you, just cut to the chase and source one online.

Susan

I agree, I am not going to spend a ton of time looking for a liquid filled gauge because I know they are not there. I am going to give a dry gauge a shot. I can get one at sears by me. That is the most time I will spend. Then I will source the liquid gauge online. It looks like Northern tool has them. Not sure what a snubber is. Ultimately I need to get the parts in pace and I can swap gauges if the dry doesn't work.

This may help you understand the role of the snubber:

http://www.tpub.com/content/engine/1410 ... 05_137.htm

It does for the dry gauge what the glycerin seems to do in the liquid-filled gauge.

My $.02: Finally got around to putting together a portafilter pressure gauge last week, using parts from Orchard Supply Hardware. All went well, except the dry gauge vibrated like hell. Returned it, ordered a liquid-filled gauge from Directmaterial.com (DCPB254L -- 2-1/2" Liquid Filled Pressure Gauges - Lower Mount
[DCPB254L:PB254L-300: 300 Psi]) for $8.59 + shipping. Arrived in three days; works just fine. (Now the Silvia, that's another story.)

Best,
Alan
--------------
Berkeley, CA
Silvia/Mazzer Mini

The gauge that comes mounted on the CC p/f set up is dry, uses no external snubber & gives clear, concise readings. I modified mine for flow & have no problems reading the pressure measurements as the needle does not fluctuate.

And there you have it.
Everyone has a different story.
I'm sticking by mine: dry gauge (on a Gaggia) fluctuated so much that it was untrustworthy.

Is there any possibility that that CC gauge (sorry, I don't know what CC means) has an internal snubber?
(I don't even know if there is such a thing).

And, how much did it cost?

And, what sort of pump is on the machine you are using it on? I'm thinking it might be a different issue with a rotary than with a vibe pump?????

Susan

I stick to this






I'd call it FACTS (at least for me)

I've try few cheap ebay DRY gauges and they work..
and even the Gauge in my SanRemo and any other machine I have with pump gauge vibrate a bit sometimes.

CC=Chris Coffee. No idea what Chris pays for them but it is very generic looking & has no markings as far as model or mfgr. I've only used it with a rotary pump so I can't comment on the vibe question except to say that he only sells one version for testing both the vibe equipped Mini & the rotary equipped S1.

I built the dry gauge for my Vetrano, and it does not vibrate much at all. Very easy to get a reading. I wonder if it is because of the rotary pump? Now, I cannot vouch for the accuracy, but it is certainly in the ballpark.

If you have a Harbor Freight in your area, they have both filled and dry gauges in stock for pretty cheap.