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Old 11-15-2010, 09:17 PM   #1
tedandlea
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Mar 2009
Dexter, Michigan
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I had been using my dial thermometer for some time, and noticed that the boiling wort was always at 206F. So I got a couple new ones. The first gave a boiling point reading of 210F, somewhat better than my original, but when I checked the melting point, it came at 37F. The second new one gave a boiling point of 222F! But its melting point was right at 32F. Since I live only a few hundred feet above sea level, I would expect the true boiling point should be 212F and the melting point 32F.

Now, since I do all grain mashing, the rest temperature is very important (I want it to be 150 to 152F). My question is - Can I trust any of the thermometers at this in-between temperature? Or is there some way to calibrate them?

 
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Old 11-15-2010, 09:20 PM   #2
Ichthy
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Go buy a lab thermometer. I don't trust the dial thermos when a couple degree difference matters.

 
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Old 11-15-2010, 09:58 PM   #3
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I just bought one of those Blichmann weldless thermometers and it was dead on nuts.

Compared it to my long stemmed dial therm and it was off by 5 degrees. Tested my cheapo digital thermometer and it was within a degree of the Blichmann.

 
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Old 11-15-2010, 11:52 PM   #4
Catt22
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This is completely normal for the bi-metal dial type thermometers. Seriously, I've had nothing but problems with them including a relatively expensive one. I gave up on them entirely and went the digital thermocouple route.

 
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Old 11-15-2010, 11:54 PM   #5
Hugh_Jass
 
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Quote:
Originally Posted by tedandlea View Post
I had been using my dial thermometer for some time, and noticed that the boiling wort was always at 206F. So I got a couple new ones. The first gave a boiling point reading of 210F, somewhat better than my original, but when I checked the melting point, it came at 37F. The second new one gave a boiling point of 222F! But its melting point was right at 32F. Since I live only a few hundred feet above sea level, I would expect the true boiling point should be 212F and the melting point 32F.

Now, since I do all grain mashing, the rest temperature is very important (I want it to be 150 to 152F). My question is - Can I trust any of the thermometers at this in-between temperature? Or is there some way to calibrate them?
There should be a nut on the back side of the dial. Turn the nut, take reading, repeat until it reads 212
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Old 11-16-2010, 12:01 AM   #6
Catt22
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Quote:
Originally Posted by Hugh_Jass View Post
There should be a nut on the back side of the dial. Turn the nut, take reading, repeat until it reads 212
Yes, then do the same at 32F, then go back and do it at 212F, then go back and do it again at 32F...rinse and repeat ad infinitum.

 
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Old 11-22-2010, 05:38 PM   #7
zymurgy101
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Quote:
Originally Posted by Catt22 View Post
Yes, then do the same at 32F, then go back and do it at 212F, then go back and do it again at 32F...rinse and repeat ad infinitum.
Doubtful many boil kettle thermometers go to 32F.
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Old 11-22-2010, 05:53 PM   #8
Mischief_Brewing
 
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I had nothing but problems with thermometers. Out of 5 thermometers I used during various brews, none of them passed both the freeze and the boil test. I was lucky enough to get a thermapen for my birthday last October and have been nailing mash temps ever since.

 
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Old 11-22-2010, 06:40 PM   #9
Bobby_M
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I view installed dial thermometers as a ballparking tool and nothing more. They are generally slow to respond and only measure a small pocket of space in the vessel. I always spot check with an instant read digital before I do anything.
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Old 11-22-2010, 07:41 PM   #10
redalert
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Don't get me started on thermometers. I have at least 4 of them and all of them give different readings. I've been brewing for 2 years and still have yet to find a reliable one. Even though Thermapens are supposed to be the shiznitz it's hard to justify spending $100 on a thermometer. I just ordered a thermocuple from Ebay for a Craftsman multimiter which gives decent temps.

 
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