# How to check thermometer accuracy??



## hunt4570 (Jun 14, 2017)

I'm sure this has been covered here somewhere but I cant find it. Just trying to figure out how to check to see if my thermometer is reading the proper temperature. I have a non contact temperature gun, but if I open the lid to use it, by the time the smoke clears to see what I'm doing I imagine the temp has changed. Is there some neat little trick to check this?

I have a new Old Country Over Under smoker with one of their "adjustable" "calibratable " thermometers but I don't want to adjust it unless I know what the temp really is..

Thanks..

Scott


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## SmokinAl (Jun 14, 2017)

Check it in ice water, it should read 32 degrees.

Then check it in boiling water & it should read 212, if you are close to sea level.

You may have to adjust for elevation if water doesn't boil at 212 at your elevation.

Al


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## hunt4570 (Jun 14, 2017)

SmokinAl said:


> Check it in ice water, it should read 32 degrees.
> 
> Then check it in boiling water & it should read 212, if you are close to sea level.
> 
> ...


Lowest temp on the thermometer is 100...

But I should be able to heat water to whatever and check it. Was hoping to do it without removing it...


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## chef jimmyj (Jun 14, 2017)

If it has a stem, Fill a zip bag with hot tap water. Measure the temp with a known accurate therm. Wrap the water bag around the smoker therm stem and hold there until the needle stops advancing. If the temps match, it is accurate. What water temp you use does not really matter as mutiple decimal place accuracy in smoking is not critical...JJ


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## uncle eddie (Jun 14, 2017)

If it nails 212F for boiling water, that single verification should give you some confidence that it is at least accurate in that general temperature range.

I run a testing laboratory and we have many calibrated thermometers.  When they are out of calibration at one or both ends of the range, or by more than 1% at any part of the range, we pitch them.  BUT, when we graphically plot the calibration results they are usually linear between the checked temperatures even if they are not reading accurate and precise.  

For instance...Even if the thermometer is spot on at boiling (212F) off by 5 degrees at freezing (32F) it would only be off by one degree at 176F and at 248F and even less so between that range.

Ed


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