Thermometer differences

First outdoor and first all-grain recipe today. Loads of fun... Had strike water at about 160 on kettle thermometer and after mixing in grains I saw it sat steady at 153 ... Put a probe electronic thermometer in and stretched the cord out and after ten minutes it was reading back up over 170.

So I panicked and found two of my wife's cooking probe thermometers. Cleaned them down and tried each and they got to about 140 and then slow climb.

So not sure where I am but I would get somewhere between 145 and 150. Kind of frustrating. Anyone else get such disparity from different types of thermometers ?

 

The dial thermometers go wonky pretty easily, I have had up to about 10* difference.

 

Yes, pretty much all thermos need to be calibrated in an ice bath. I just did a writeup on thermo types and sent it to Austin. Perhaps it will get published. Most dial type thermos have a screw or nut you can turn on the stem to move the needle to the correct temp. If the dial does not go as low as 32F, you'd have to boil calibrate it - get boiling water and set the dial to 212F

 

No, set the temperature at the proper boiling point for your elevation. Unless you are at sea level, 212F is not the proper temperature.

The best way is to have a calibrated laboratory standard thermometer and to make sure your working thermometer is calibrated to that standard in the typical mashing temperature range, say 150F.

 

^ Good points

 

The typical cooking thermometers where the probe is connected to a cable which then goes into the main unit are very problematic in brewing. These frequently develop "shorts" such that the readings are totally erroneous.

Your best bet is a standard "pocket" digital thermometer with quick response time and low variance of accuracy. A couple that are well regarded (aside from the $100 ThermaPen) are:

CDN ProAccurate: http://www.amazon.com/dp/B0021AEAG2/?tag=skimlinks_replacement-20
ThermoWorks RT600C: http://www.amazon.com/dp/B002GE2XF8/?tag=skimlinks_replacement-20

I have and use the latter.