Please critique my thermocouple contraption

Need help with equipment usage or want to share your latest discovery?
guydebord

Postby guydebord » Feb 09, 2019, 5:36 pm

First time venturing into this and would love to have a critique and use recommendations of this contraption I made to measure the brew temperature on my machine. I have been using Eric's thermometer but wanted something more precise... Is it enough???? Many thanks in advance for your replies.

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SJM

Postby SJM » Feb 09, 2019, 8:00 pm

Here is a link to the documentation for the one I built many years ago:
Building a DIY Thermofilter

What yours seems to be missing is something to mimic the puck and to slow the flow of water down.
How critical are those points? At this juncture I can't tell you, but they were considerations when Fred and I put one together.

Susan

RockyIII

Postby RockyIII » Feb 09, 2019, 8:27 pm

Guy,

Looks good. Will you be using ground coffee in the portafilter basket?

Rocky

SJM

Postby SJM » Feb 09, 2019, 8:39 pm

What is the clear stuff holding the thermocouples in place where they go through the portafilter?
And if you already said and I missed it, I apologize.

Susan

guydebord

Postby guydebord » Feb 09, 2019, 9:01 pm

RockyIII wrote:Guy,

Looks good. Will you be using ground coffee in the portafilter basket?

Rocky


Should I? I figured that as long as the water touches the thermocouples it should be ok, no? Or am I missing something?

guydebord

Postby guydebord » Feb 09, 2019, 9:03 pm

SJM wrote:What is the clear stuff holding the thermocouples in place where they go through the portafilter?
And if you already said and I missed it, I apologize.

Susan


Its just clear silicon, I had some and figured out it could help hold the thermocouples in place and thankfully it worked perfectly. So far....

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another_jim
Team HB

Postby another_jim » Feb 09, 2019, 10:38 pm

guydebord wrote:Should I? I figured that as long as the water touches the thermocouples it should be ok, no? Or am I missing something?


I probably should put this into Wikipedia or something: The idea of a thermocouple in the PF is to measure the temperature the puck experiences during the shot. There are two techniques used.

The first is the Schomer PF: a regular basket and PF with the thermocouple inserted. You fill it with coffee, make a shot, and get a reading of the what's happening during the shot. Usually the themrocouple is set up so that it's just above the puck, but you can try different variants.

The second is the Scace thermofilter. Since making actual shots to take repeated readings is very tedious, it would be nice to have a fake, reusable puck. The Scace has this, some foam to mimic the absorption and thermal mass of the puck, and a flow restrictor so the flow is comparable to a regular shots. Greg works for NIST, so his set up is uberprecise and the gold standard; but you can rig something similar ("the ghetto Scace") by taking a spare basket, gluing all the holes shut, and pasting in a pad of sponge material. Then partly drill out one hole and measure the flow. It should be roughly right. We were rigging these up for a couple of years before the the thermofilter came out, so you are not stepping on anyone's toes by making one.
Jim Schulman

RockyIII

Postby RockyIII » Feb 09, 2019, 10:47 pm

guydebord wrote:Should I? I figured that as long as the water touches the thermocouples it should be ok, no? Or am I missing something?


Yes, for accurate readings you will want to simulate the water flow during an actual shot. Jim described it more fully.

Rocky

guydebord

Postby guydebord » Feb 10, 2019, 12:21 am

another_jim wrote:I probably should put this into Wikipedia or something: The idea of a thermocouple in the PF is to measure the temperature the puck experiences during the shot. There are two techniques used.

The first is the Schomer PF: a regular basket and PF with the thermocouple inserted. You fill it with coffee, make a shot, and get a reading of the what's happening during the shot. Usually the themrocouple is set up so that it's just above the puck, but you can try different variants.

The second is the Scace thermofilter. Since making actual shots to take repeated readings is very tedious, it would be nice to have a fake, reusable puck. The Scace has this, some foam to mimic the absorption and thermal mass of the puck, and a flow restrictor so the flow is comparable to a regular shots. Greg works for NIST, so his set up is uberprecise and the gold standard; but you can rig something similar ("the ghetto Scace") by taking a spare basket, gluing all the holes shut, and pasting in a pad of sponge material. Then partly drill out one hole and measure the flow. It should be roughly right. We were rigging these up for a couple of years before the the thermofilter came out, so you are not stepping on anyone's toes by making one.


Many thanks! Jim. It makes sense and so now I will work on the ghetto Scace. The hole gets deeper...

guydebord

Postby guydebord » replying to guydebord » Feb 10, 2019, 12:26 am

Edit: Im now seriously considering just buying the SCACE :evil: