Thermometer Calibration Blues

I have two thermometers and they argue like an old married couple about the temp. It's hard to know who to believe.

Mabel is a typical floating thermometer with blue goo inside. In the 130-170 range, she reads four degrees hotter than Abe.

Abe is a big face dial thermometer with a long stem. He reports temperatures much faster, but reads four degrees cooler than Mabel.

The rub begins in that difference between the two changes with the temperature range. For instance, they are off only by a degree or two at 70, but off by eight degrees at boiling. If I adjust Abe up at boiling, he then reads higher than Mabel at 70.

Who am I supposed to believe? What's the best way to calibrate? I'm in Fort Collins Colorado so my altitute is 5k feet making my boil temp 203.

It sounds like you've done all the right things trying to calibrate them at boiling.

It depends why you want an "accurate" thermometer. I'd say the absolute value matters less than the consistency of the reading. Pick one thermometer and use that for all your measurements. That way any recipes you make will be consistent and repeatable.

I bought a digital probe thermometer for like $20 at Target. It's accurate at freezing and boiling, and I would never think of going back to an analog thermometer again.

okay, these aren't cheap, but omg, they're awesome!

several Thermapen users here.

you know...if temperature is important to you...

thermapen. they calibrated it for me.

I bought one of these traceable lab thermometers and I use it to check/calibrate all of my others. It's a bargain at $11.95:

http://www.carolina.com/product/equ...).do?keyword=745416&sortby=bestMatches&page=1

I have several digital thermocouple type digital thermometers that I use for brewing. I also have several of the worthless bi-metal dial thermometers that are now paperweights. Even the relatively expensive one was way off and not consistent throughout it's range. The Thermapens have lots of happy endorsers, so they must be pretty good, but I'm not fond of the short, non-interchagable fixed length probe. That was a deal killer for me.

One of my old blog entries has an entry on thermometer calibration. You can probably find it by clicking somewhere over

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Where it says blogs.

http://www.bedbathandbeyond.com/pro...ogle&utm_medium=organic&utm_campaign=shopping

This is what I use. It's really great. It does everything I need it to. You can set an alarm for when it hits a certain point, which is handy for heating up my sparge water. I use it for roasts and cheesemaking too. It also works as just a timer without the probe. I've never had to replace the batteries, either, and I've had it over a year now.

I will second the thermapen. I just bought one a couple weeks ago...made my brew day a breeze with accurate strike, mash, wort, fermentation temps...all spot on. Can't go wrong with a thermapen if ya got the extra ching.

My wife has used thermapens as a sous chef. She wasn't impressed with the durability, but a pro kitchen setting is a lot harder on tools than a homebrewing setting. Just don't drop the thermapen in your kettle and you'll probably be fine.

Yeah, I'm not wild on the idea of spending another $100 bucks to get the thermo of my dreams. And the thermopen is the thermo of dreams without a doubt.

I appreciated the calibration blog entry, but my problem is that they read differently at the different extremes. If I adjust them to be together at freezing they are different at boiling.

I think the problem is Abe. I'm going to trust Mabel and just use his him as a relative measurement.

Thanks for the help guys.

I went with http://www.amazon.com/gp/product/B0021AEAG2/?tag=skimlinks_replacement-20 to double check my HLT temps as well as mash temps as I recirculate through my RIMS system. I am super happy with it, it reads fast and after I calibrated it at freezing temps it was right on for our altitude for boiling temps. Hope that helps some.


Chromados

Im having this problem too> I had a problem with my digital which was 10 deg too high for some time then after putting it in a boil, it recalibrated itself. Is this due to maybe having to change batteries, I also noticed i accidentally stuck some of the wire in so maybe im finding a trend here as the probe was immersed with it,seems like this is what happend last time when the whole thing was in boiling or ice water.Anybody???/ I have a refrigerated stand up thermometer that i think is right, im just thinking ill stick this electric one in boiling water to see if it recalibrates itself. HOw annoying to not no your actuall temps. I have a dial thermometer that i dropped and had to re calibrate that also. Sucks!
Allso does anybody know if your boil is a certain temp. Most of the time when my damn thermometers were working right, boil was 212,recently they have been like 217.Is this not right or is it sometimes higher???
I also messed up a target mash because of this i was mashing at 140's when it should have been 150's. Pure suck.The weird thing is i got super high mash efficency but will have a light bodied beer when i wanted body. Oh well. way to go thermometer, i was trusting you!

So I have a thin candy type thermometer with alcohol as the medium. At boil it reads 207 and I live in San Diego, basically sea level.

The other is a meat thermometer and it reads 3-4 degrees less at boil. Since I extract brew, I am only concerned with my steeping temp

Will look for a better one down the road

Toy4Rick