Thermometer for measuring fermentation temps

[blackstrat5]

Currently, the fermentation temps that I see are just from the probe for the Johnson Controller on my chest freezer. The probe is taped to the side of my better bottles/carboys under a towel for insulation. This is so the freezer doesn't cycle too long and overshoot lowering the temp of fermentation.

I'm wondering if the actual fermentation temp doesn't get quite a bit higher than that probe is measuring. I was thinking about getting a probe/cooking thermometer and letting it hang from the stopper in the beer and keeping an eye on it that way. Or building an arduino based device to measure a probe in the beer and the ambient temperature of the freezer. (I wasn't able to find a device I was happy with that would meausre the temperatures with a waterproof probe, but I may just have not been looking hard enough).

I guess I wanted to know if anyone has done such a thing before here, or has any suggestions on what the best route might be. If I go the arduino route, it'd be a little pricey but I could log the temps through wifi/ehternet and check on it remotely if I really wanted to. On the other hand, I may find that the controller probe really is measuring the temp of fermentation rather accurately. Sny thoughts? Comments?

 

[Fat_Bastard]

http://www.williamsbrewing.com/THERMOWELL-FOR-PLASTIC-CARBOYS-P2596C100.aspx

 

[blackstrat5]

I could get a thermowell for measuring the beer fermentation temp, but I was concerned if I'm using the controller probe in the thermo well, the freezer would overshoot the temp due to the thermal mass of the volume of beer.

 

[Quaffman]

Jamil talked about an experiment someone ran a few years ago measuring the difference between the wort in the middle of the carboy compared to the temp measured on the outside of the carboy. He said that the temp only differed by 1/2 a degree and determined that the method you are using works perfectly fine for gauging the temperature of the wort.

 

[blackstrat5]

Jamil talked about an experiment someone ran a few years ago measuring the difference between the wort in the middle of the carboy compared to the temp measured on the outside of the carboy. He said that the temp only differed by 1/2 a degree and determined that the method you are using works perfectly fine for gauging the temperature of the wort.

I've heard that expirement and it might be true. I guess I have my doubts and a paranoid suspicion and if I do my own expirement I may find that taping the probe to the side is accurately measuring the temp through fermentation. But, it would be cool to see a compiled graph of temp data through fermentation showing what the temp was at the height of fermentation. At the very least it'd give me peace of mind.

However, in my quest for finding an accurate way to measure the temp of my fermenting beer. I was wondering, how well would a PID controller such as (http://www.amazon.com/dp/B002PIM3R8/?tag=skimlinks_replacement-20) be at not causing the freezer to overshoot temp if it's probe was in a thermowell, directly in the fermenting beer.

 

[Quaffman]

If you do I'd be really interested in seeing the results of that experiment.

 

[maida7]

This thermometer is very accurate and the probe is good in liquids. I use it to measure mash temps.

BTW my temp controller probe is taped to the side of the fermenter and it works great.

 

[AnOldUR]

Showing that the temperature during very active fermentation is the same in the center of the wort as it is in the water bath with a ThermoWorks Long-Stem Digital Thermometer. Fits nice into the small hole on a carboy cap. No need for a thermowell.