Dial Thermometer - Recommendations?

[Mike123]

Any one have a recommendation on a good dial thermometer that can be mounted directly on a brewpot and not get damaged by overheating during normal use? Preferably one with a 1/2" NPT male connector. I've been using a readily available dial thermometer (B1 and B2) on my Keggle for years. (Vendor names omitted). Recently I tested them, along with every thermometer in my household to see which of them are accurate and here are my results. Turns out the B1 and B2 thermometers are way off. I am pretty sure I damaged them long ago by exceeding the case temperature maximum. I expect the brewpot metal exterior, with a propane burner under it, gets a lot hotter than 212F. I'm now using the T1 wire probe thermometer for mash temperature, but I still would like a dial thermometer installed on my Keggle.....which is the recommendation I am looking for. JEGS makes a liquid filled engine coolant thermometer intended for installation on engine intake manifolds, and that means it can probably hold up to at least 212 F. But I am not sure it is food grade so I don't plan to use it. I'm thinking the ultimate answer here is to NOT install a dial thermometer on the brewpot. They are not designed for that environment.

 

[Dland]

I have dial thermometers on my keggle brew vessels also. Nice to have back up/reality check to digital heat sensor.

I got mine off ebay, eliminating new imported listings, picked up some new old stock/open box quality units. Two of mine are Ashcroft brand, do not recall the other, there are several quality brands that cost a lot new, but can usually found surplus for the cost of a cheap imported one.

 

[mabrungard]

Come on, a bimetallic thermometer will never be a precision device. However, they can be a durable and reasonably accurate tool when you've checked and adjusted their reading IN THE TEMPERATURE RANGE THAT YOU'RE INTERESTED IN.

Get a well-built and readable dial thermometer and compare its reading to a certified thermometer while both thermometers are in warm water bath, say in the 150F to 170F range. Don't try and check a dial thermometer's calibration by sticking it in boiling water and an ice bath. Those thermometers are just not that linear.

 

[mongoose33]

I think that you're barking up the wrong tree if you're looking for a dial thermometer that can handle propane heat. The answer is to have a heat shield to protect the thermometer. That can be made out of aluminum sheeting you buy at the home store or some stainless sheet goods you might have lying around.

Many of the dial thermometers I've seen have an adjustment on the back (typically a screw). If you want perfect accuracy a dial thermometer isn't likely to cut it, but it'll come close.

On a BK, and if I were using an immersion chiller (or even a CF chiller recirculating back into the kettle), I'd want the accuracy on the low end of the scale, so I was close on the temp when time to transfer to the fermenter. I wouldn't care too much about the high end, just enough so I could tell when the kettle was getting close to boiling.

So ask what temp range is most important, and get a heat shield. If you do that, you might even open up the opportunity to use non analog thermometers.

 

[Mike123]

OK good points. I'll calibrate the B1 bimetal thermometer roughly in the middle of the mash temperature range (150F), which is my primary range of interest. That way I can see from a distance when I'm getting close to mash temperature. I'll confirm the mash temperature with my digital thermometer when I'm checking pH. It will also probably read closer to 212F at boiling than when calibrated at room temperature.