Thermometer calibration

[BOBTHEukBREWER]

Is it possible to calibrate a thermometer without direct comparison to a master thermometer? I was wondering if there was a wax or a chemical misture with a melting point of 66 deg C, so plotting a cooling curve from 80 to 50 would show the points of inflection (if that is what they are called). My thermometer WAS calibrated to national standards 5 years ago and was reading 67 against a true 66, and I have no idea if this is still the case. I doubt that melting ice or boiling water would help, as those fixed points are well away from 66 deg C.

 

[MalFet]

I've seen mention of other methods from time to time, but they are usually complicated beyond homebrewer capabilities. The trouble with wax would be that you'd see inconsistent temperatures at different points within the sample.

Most practical calibrations I have seen end up checking both a melting and a calculated boiling point and then assume any error is linearly distributed throughout the range. Or, better yet, they buy a good, pre-calibrated thermometer from a scientific supply store.

 

[Catt22]

Get one of these to use as your benchmark:

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

They are certified traceable and the price is right. I like that the graduations are large and easy to read.

 

[scotty83]

I think the best and simplest way to calibrate a thermometer is to follow the boiling point & freezing point methods (See here). These are proven accurate methods. The only problem here is if you don't have the correct temp that corresponds to your elevation if you're using the b.p. method.