Inline Thermometer Build - 3/4" - Simple Simple

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
passedpawn

passedpawn

WYSIWYG
HBT Supporter
Joined
Apr 23, 2009
Messages
37,084
Reaction score
17,848
Location
☀️ Clearwater, FL ☀️
This was meant to be similar to the Blichmann Thrumometer, but with a 3/4" bore instead of the smallish 3/8" bore of the commercial product. And, if you don't value your time at all, it is cheaper.

Clicking on pictures gets you the big ones.

Parts list:
  • (1) small fishtank thermometer - $2.29 Petsmart
  • (2) 1/2" NPT female thread x 3/4" slip - $4 ea. Home Depot
  • 1.5" 3/4" copper pipe - scrap bin!

When finished, clear shrink tubing would be best, but I didn't have that. I wrapped a layer of clear shipping tape around it. Haven't tested, but I predict success:)







 
Simple and efficient. :)

I build a very similar piece for my inline aerator. It's just a copper tee with 1/2" threaded fittings soldered on plus a stainless 2 micron aerator stone.

However, I stuck the thermometer to a thin piece of aluminum flashing that I then velcro'd around the pipe. This is so I later remove the thermometer and boil the assembly for sanitary purposes. Those stick-on thermometers ain't gonna survive boiling water...
 
lamarguy said:
Those stick-on thermometers ain't gonna survive boiling water...
Click to expand...

No, they won't. At least I am sure the tape would let loose.

Mine won't ever be submersed, though. I circulate boiling wort through my whole cooling system for 15 minutes before I turn off the heat. Using a pump, of course. This "thrumometer" will be sanitized in that way. That is also how I sanitze my tubing and plate chiller.
 
passedpawn said:
I circulate boiling wort through my whole cooling system for 15 minutes before I turn off the heat. Using a pump, of course. This "thrumometer" will be sanitized in that way. That is also how I sanitze my tubing and plate chiller.
Click to expand...

Blichmann specifically says not to heat the "thrumometer" higher that 140F. I imagine all liquid crystal thermometers have a similar maximum temperature. Just sayin'... :eek:

In no case exceed 140oF as this will permanently damage the liquid crystal temperature elements and cause the thermometer to lose accuracy.
Click to expand...
 
I don't know if the high heat will actually damage the thermometer, but it's sure pretty cheap and easy to find out!
I do think the adhesive will let go when you pass boiling wort through it, though.
Perhaps you could encase the whole thing in clear heat shrink? That'll hold the thermometer to the copper regardless of the adhesive surviving!
Granted you could get nasties under the shrink after washing a few times, but it is on the outside... Maybe the adhesive lined clear heat shrink would be a better way to go?
 
SweetSounds said:
I don't know if the high heat will actually damage the thermometer, but it's sure pretty cheap and easy to find out!
I do think the adhesive will let go when you pass boiling wort through it, though.
Perhaps you could encase the whole thing in clear heat shrink? That'll hold the thermometer to the copper regardless of the adhesive surviving!
Granted you could get nasties under the shrink after washing a few times, but it is on the outside... Maybe the adhesive lined clear heat shrink would be a better way to go?
Click to expand...

yea, I mentioned the shrink tubing in my post. I just couldn't find it quickly. Anyhoo, if the tape fails, I will go and find the tubing.
 
If recirculating boiling wort through it is a problem you could always get another set of quick disconnects and sanitize it with starsan then put it on after you are done recirculating. Probably kills the whole point of it being cheap then though.
 
SweetSounds said:
I missed that! Sorry :)
Click to expand...

1.25" tubing would be perfect. I doubt I'll find it locally, but it is available on Ebay. First I'll test the thermometer at temp... if it squirts its guts all over, then I'm back to the blackboard. If it survives, I think I'll get the tubing. $10 for way too much tubing. I'll probably build 10 of them and sell them to cover my costs, plus some.
 
Good plan.
I'd use it with a few brews first, and cross reference the crystal thermometer with a thermometer rated for temp to see if the aquarium thermometer does any drifting after being boiled a few times. I doubt it will melt or blow up, but heating those little crystals to 200 degrees over and over could "re-calibrate" them?
 
I have a fermometer on a steel drum that gets up to 100 deg C when I boil water in it to sanitize the inside. No damage at all and it retains the same "calibration". You will be fine.
 
Quick update. I used this thermometer on 2 10-gallon batches and it performed perfectly. I run my boiling wort for 15 minutes through it, so I was worried the LCD temp strip would die. No worries now!

[edit] oh yea, the packing tape held on perfectly too. So, I won't be needing the clear shrink tubing. We'll see how it looks in a year.
 
Bobby_M said:
This is a great DIY but I wish they made the LCDs that go down to at least 45F for those lagers.
Click to expand...

Yep, I'm with you there. I pitch lagers between 55-60, and this strip doesn't get there.

I put off this simple build for months while I canvassed all the pet and fish stores in town. "Colder" ones might exist on the internet, but I can't entertain the idea of paying for shipping for a $2 strip.
 
Long term durability tests did not go well. After about a year the LCD is non-functional. Perhaps a better one would work longer, but I'm just gonna shove a normal thermometer into a "T" and do it the old fashioned way. Oh well.
 
passedpawn said:
Long term durability tests did not go well. After about a year the LCD is non-functional. Perhaps a better one would work longer, but I'm just gonna shove a normal thermometer into a "T" and do it the old fashioned way. Oh well.
Click to expand...

It was a good idea, nice and compact. I suppose you could always just purchase 10 or so of the thermometers and swap them out when they begin to fail.
 

Similar threads

M
Cheap, simple, portable hoist rig
Replies
2
Views
1K
doug293cz
doug293cz
H
Tons of fittings: tri-clamp, stainless, valves, keg couplers, temp control, and more
Replies
12
Views
2K
hafmpty
hafmpty
M
For Sale *** EVERYTHING SOLD *** Hardware Cleanout
Replies
5
Views
1K
matt_m
M
S
Inline Thermometer issue - Northern Brewer Stainless CFC
Replies
3
Views
802
Bobby_M
Bobby_M
duncan.brown
Keezer and bar build
Replies
13
Views
6K
TheMadKing
TheMadKing
CornyKegs 300

Latest posts

Back
Top