*WARNING* Stupid thermometer mistake

[BRUbaker]

I can't believe i did this! I work in research for God's sake!

CHECK THE CALIBRATION ON EVERY THERMOMETER YOU USE!

I don't like the stem thermometers so i got a dial version. Why i never checked it against the mercury one i can't explain. I found out it was 8 degrees off (low) during a brew session with a mentor. Which explains why I've been frying my beer.

Can i swear on this forum cuz i surely want to right now! At myself...

 

[SlimeyBooger]

I have a digital thermometer that decided to lose calibration halfway through cooling the wort of a previous brew. It took an hour and a half to cool the wort to what I thought was 80 degrees. I later found out that the thermometer was over 10 degrees high.

 

[Number68]

the first thermometer I had was only accurate above 100. was able to mash fine, showed 215 when I had my nice rolling boil, when I went to cool, it cooled to 100 and stayed there. an hour later it dropped to 85, and wouldn't go any lower. took another thermometer, and it was right at 74.

 

[william_shakes_beer]

the first thermometer I had was only accurate above 100. was able to mash fine, showed 215 when I had my nice rolling boil, when I went to cool, it cooled to 100 and stayed there. an hour later it dropped to 85, and wouldn't go any lower. took another thermometer, and it was right at 74.

sooooo

When you have 2 thermometers that give 2 different readings, how do you determine which is correct?

 

[frazier]

^^^ Good question. That's why I have three.

I invested a lot of anxiety trying to troubleshoot some attenuation problems I was having. I decided that my digital thermometer must be reading low, causing me to mash high. So I bought a floating thermometer at the LHBS, but it gave identical readings to my digital. So I picked up a lab thermometer, which said the same thing. So I'm back to square 1 on my attenuation issue.

 

[DynamechGT]

Boiling water should read very close to 212F (100C)
Iced water should read very close to 32F (0C)

Check at both points.

If your thermometer is wrong, make an offset chart to show exactly what yours is reading. Or, better yet, go get a good thermometer!

This is very improtant to your brew and absolutely worth the minimal effort to check.

 

[dpittard]

sooooo

When you have 2 thermometers that give 2 different readings, how do you determine which is correct?

Calibrate to boiling water if you need higher end accuracy or put a bunch of ice into some water, wait 10 to 15 minutes, and then calibrate to 32 degrees for lower end accuracy.

 

[HopSong]

Or.. "better" yet.. calibrate at both ends.. 32* and 212* (@sea level). Should give a better idea of general calibration.

I'm glad this post came up as I just opened my new/old Cajun cooker that came with a long stemmed thermometer. I need to verify what it's doing.

 

[william_shakes_beer]

I have a turkey fryer that came with a long stem thermometer that I use for my boil. It goes down to 50, but i would certainly not trust it at the freezsing level. Wouldn't a mercury thermometer *always* be accurate, since it is based on expansion and contraction of a metal with known properties?

 

[DynamechGT]

As a professional chemist, my confidence levels for consumer level thermometers are:

[highest to lowest]
digital thermoresistive (be aware of probe range)
mercury glass bulb
alcohol glass bulb
infrared "at a distance"
bi-metal spring dial gauge (most cheap kitchen ones)

Don't trust any thermometer outside of it's recomended range. Don't automatically trust any thermometer inside it's normal range - calibrate and/or determine offset.

I'll restrain myself from ranting about the minute details.

 

[Misplaced_Canuck]

I've had some alcohol ones "separate": One small speck (1/8" to 1/4") of alcohol had separated from the main alcohol line.

I had to bring them over the top of the alcohol line to fix them. I used vegetable oil in a sauce pan to do that. Be careful not to overshoot as vegetable oil will easily go to 300F+ range (and the thermometers don't!). Hold them upright when they reach the top of the line and they will reconnect.

M_C