Measuring Pump Pressure

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torretta

Postby torretta » Aug 07, 2013, 12:23 pm

I've been reading about how flowing water when measuring pressure provides a more accurate pressure reading.

Has anyone added a 3/8 tee-valve to the spout of a portafiler with gauge at the end of the handle to allow water flow while measuring the pressure? If so, any tips would be appreciated.

Attached are photos of the portafilter with pressure gauge that I use to measure rotary pump pressure.

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torretta

Postby torretta » Aug 07, 2013, 3:02 pm

Hi Dan, thanks for the reply. I have read those topics which were very informative.

However I am looking for some discussion specific to the portafilter with a gauge at the end of the handle like the one in the pictures above. I am unsure what I will find when I start to dismantle the portafilter spout and whether adding a tee to this type portafilter is worthwhile.

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HB
Admin

Postby HB » Aug 07, 2013, 6:02 pm

Eh, I've used both types of pressure portafilters (flow vs. static) and the readings aren't that different. Usually they differ by 0.5 bar with the static ones reading slightly higher. You will get nearly the same reading simply by not locking in the portafilter tightly so it drips a little.

That said, unless you're calibrating equipment to an agreed-upon standard, I don't see any value in knowing the precise brew pressure. If the goal is better espresso, it's more useful to treat the gauge reading as X and then compare tastes/textures when bracketing the pressure at X, X+1, X+2, X-1, and X-2; you'll learn a lot about if and how brew pressure affects your espresso.

If it's just a matter of curiosity, I would try removing that closure nut on the portafilter and replacing it with a coupling/needle valve combo. Don't be disappointed if the reading is nearly the same as the static flow reading.
Dan Kehn

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cannonfodder
Team HB

Postby cannonfodder » Aug 08, 2013, 9:34 pm

Getting it set to the proper flow rate is the difficult part.
Dave Stephens