Thermometer Problems

Hey All,
I have tried several thermometers now(candy, instant read dig and analog, digital probe) and have yet to find one that stays even close to accurate. The one I thought was the best (digital wireless) gave me a 221 deg F reading yesterday on less than boiling water. Does anyone have any suggestions?
Thanks

A good glass scientific thermometer that uses a non-mercury liquid (red dyed alcohol or mineral spirits), in my opinion, is the best and most reliable.  Anything based on a thermocouple or other electronic sensor has the potential to degrade and drift.  Bi-metal spring based dial thermometers are less accurate yet. 

Make sure that the range is suitable for brewing.  Candy thermometers are made for pretty high temperatures so small changes are hard to detect.

Also, when testing the calibration of your thermometer, don't forget boiling point is elevation dependant.  If you live at elevations significantly above sea level then water boils at temperatures below 212 F.  Ice water is a better indicator of 32 F because it is not nearly as affected by atmospheric pressure.  If you know the elevation of you locality, or can look it up, you should use both points to calibrate your thermometer.

IMHO the 10-15 dollar analog one that they usually sell at a local home brew shop are the best for the money. You can calibrate them easily and replace for cheap if need be. Mine has worked just fine for a long time. Also it depends how and where you store them. Dont just throw it in a drawer. I keep mine with my hygrometer in my Erlenmeyer flask up on a shelf when not in use. If you bang it around at all or drop it recalibrate it before use. If you bend the probe end at all you better buy a new one. Digital ones are crap, dont waste your money!

http://www.midwestsupplies.com/review/product/list/id/3193/

The reviews are mostly good on this except for the few who think you cant calibrate it or should seal it up with Jb weld. The nut on the back IS for calibration and should not be sealed with JB weld duh!

Also, when testing the calibration of your thermometer, don't forget boiling point is elevation dependant.  If you live at elevations significantly above sea level then water boils at temperatures below 212 F.  Ice water is a better indicator of 32 F because it is not nearly as affected by atmospheric pressure.  If you know the elevation of you locality, or can look it up, you should use both points to calibrate your thermometer.

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DaveinPa said:

Ice water is a better indicator of 32 F because it is not nearly as affected by atmospheric pressure.  If you know the elevation of you locality, or can look it up, you should use both points to calibrate your thermometer.

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I occasionally calibrate my $6 standard home-brew-store glass thermometer along with a $10 digital (Accurite?) from Target in an ice slurry at 32F. 

I do like the reaction speed and size of the digital on brew day, and find it easier to read while stirring a mash or cooling the wort.  I keep it in a tall tasting glass filled with Star-San during wort cooling. 

Thanks for the replies guys. Definately getting away from digital probe types. Has anyone tried an infrared instant read style? I know it reads surface temps, but if the wort is stirred I think it would be ok.

Actually I have one from working as a heating and cooling installer and have never thought to use it. My next brew day Ill try it and let you know! It might be a bit because I brewed yesterday and have nothing planned for the next batch.

dnd0327 said:

Thanks for the replies guys. Definately getting away from digital probe types. Has anyone tried an infrared instant read style? I know it reads surface temps, but if the wort is stirred I think it would be ok.

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I tried one, but found it to be completely inadequate for brewing. Testing it on my 153 degree mash, I was getting surface temp readings of less than 120. It might have just been my infrared thermometer wasn't a high enough quality instrument, but I tried it in several other cooking and brewing instances and found the measured surface temp wasn't even close to the actual internal temp.

Scott

I use a infrared thermo to check on yeast starters, both  liquid and dry rehydrations. 

And to verify priming sugar is cool enough to add to beer for bottling.

Results...The infrared cannot read water, goes straight thru (good for finding cold spots in your house however!). The 2 most accurate tools I have are the $6 floating type from my LHBS and an analog meat thermometer. Thanks for the feedback.

I have yet to find a thermometer that I don't have to calculate almost every brew day...and I have collected a number of well known brands and types.  The best so far is the cheap floater from the LHBS and a certified glass Mercury lab thermometer off EBay as a backup/standard. 

Anyone have a very dependable one??

I use a restaurant supplied chefs digital Taylor .When I first used it I tested with boiling water at sea level found it to be off by 9 degrees ,since then it has been consistent as I check it before  every brew day.  Their not cheap .

The larger the range, the more variance a thermometer has.  I used to use two or three in my mashtun.  Like the saying goes, "A man who has two watches never knows what time it is."

I looked at more expensive ones from mcmaster-carr but i like to keep the beer making simple.

I have one floating that seems to be accurate in my mash range and go with it.  Seems close enough for me and the beers pretty much come out with the body characteristic I am shooting for.