Thermometer Off

[rodwha]

I have 4 thermometers that I use while mashing. I place one in the center of my mash and one along the edge, and then I use 1 in my brew pot with the leftover water that I dunk my grain bag in prior to placing it into a colander and pour my sparge water into, which is where the 4th goes.

Yesterday I noted that in my mash I had a temp in the low 140's and the other in the mid 150's. I assumed it just needed to be stirred. But when I checked later I still noted the difference which prompted me to investigate. Eventually I place all of my thermometers next to each other and found the offending thermometer.

Is this trash or can I find the actual temp difference and adjust it? Is this something in which the temp will always be off by the 12-15* or is it a sliding difference?

 

[m00ps]

How many threads have you started in the past 20 mins? haha

I don;t think you need more than 1 thermometer for checking mash temps as long as its accurate. I have a single one built into a weld on my pot and it shows 212F at boiling so I figure its right. I'm guessing you're using that aluminum pot you mentioned in another topic as a mash tun. You will get thermo stratification using an uninsulated tun like that. I stir my mash every 10 min or so to redistribute the temps. My thermometer, closer to the edge of the pot, always has dropped by maybe 3-4 degress but when I stir it up, goes right back to the target temp

any thermometer that you know is off by 12-15 degrees would be less useful than sticking your finger in the mash and guessing in my opinion...

 

[NightriderBrewing]

If it is a stick/probe type thermometer it likely has an adjustment nut where the probe meets the dial. Most commercial thermometers are adjustable and should be calibrated every so often as they can get off as they are bumped and knocked around. If you post a pick I would be able to tell for sure.

 

[rodwha]

My mash tun pot is insulated in a large plastic pot with expanding foam as per the pot koozie idea. In theory it's great…

I've always noticed a difference in temps (~2-5*) between the 2.

Yea, I'm leery of using an off thermometer. But I still need an extra one, and so this would mean I'd need 2 more. Not to mention I hate wasting money/stuff.

 

[rodwha]

I use floating thermometers. No adjustments...

 

[metanoia]

I can't wait to move to dial thermometers. Not only do I live in constant fear of dropping my glass floating thermometer (has happened before), but like you said, there's no way to calibrate it other than adding/subtracting every time you read it. What a pain...

 

[rodwha]

I decided to check it against another I have. It was ~5* higher at room temp. I microwaved some water for 3 mins and checked it and it was almost 10*. As it doesn't seem constant I'll be trashing it and replacing it.

Having broken a thermometer and a hydrometer I keep an extra (usually).

It may be a bit overkill to use 2 in my mash tun but it makes me fell better. And who doesn't like to fell better?

 

[Smellyglove]

Dump the offset thermometer. A thermometer and hydrometer are your most important tools for brewing. And an accurate one doesn't need to cost much. Taking the annoyance out of brewing because you don't trust your thermometer or have to add or subtract values will make you a happier man.

 

[rodwha]

Indeed! I don't want to need to figure out how far it may be off at certain temps. Were it a matter of just subtracting 5* I'd likely keep it until I bought 2 more, but needing to keep a record of where it likely is is a bit too much.