Author Topic: Thermometer calibration  (Read 7178 times)

Offline mheinemann

  • BeerSmith New Brewer
  • *
  • Posts: 1
  • BeerSmith 2 Rocks!
Thermometer calibration
« on: November 24, 2013, 03:20:01 AM »
I have been brewing for about 1 year with 6 batches under my belt.  Most of my beer comes out OK. However, in the quest of fine tuning, I put my thermometer in boiling distilled water and it went off the scale at 220 degrees. Then put it into a bath of distilled water with ice in it which read 45 degrees.  Then after dialing it in at 32 degrees, put it back in the boiling water and it read 200 degrees.  All three thermometers are off by at least 8 to 25 degrees. 

Question is, do I calibrate it at 212 degrees and call it a day or is there a better way to do it?

Offline brewfun

  • BeerSmith Grandmaster Brewer
  • *****
  • Posts: 2304
  • Malt dust is just alcohol's glitter
Re: Thermometer calibration
« Reply #1 on: November 24, 2013, 06:15:07 AM »
 Calibrate it to 212. There is a slope where it's less off at higher temperatures because that's where you'll use it the most.

Better yet, invest in a higher quality thermometer, like a Blichmann or Fermentap.
Beer Appreciation is the space between pints.

Offline ghwren

  • BeerSmith Master Brewer
  • ****
  • Posts: 83
Re: Thermometer calibration
« Reply #2 on: November 24, 2013, 07:06:25 AM »
Here's a proper way to perform an ice bath from the folks at Thermoworks:
http://www.thermoworks.com/learning/thermapen101_creating_an_icebath.html

My three so called NIST Traceable lab thermometers were off by similar numbers, but my Thermapen registers 32.1F every time. Expensive yes, but they occasionally go on sale.

KernelCrush

  • Guest
Re: Thermometer calibration
« Reply #3 on: November 24, 2013, 08:17:59 AM »
what type of thermometer are you calibrating?  My experience with homebrew shop mercury 'lab' thermometers was similar. I would get one good one, calibrate, and use it for all readings.

Offline MaltLicker

  • Global Moderator
  • BeerSmith Grandmaster Brewer
  • *****
  • Posts: 2004
    • Blue Ribbon Brews
Re: Thermometer calibration
« Reply #4 on: November 24, 2013, 09:40:46 AM »
http://thermoworks.com/products/low_cost/rt600c.html


I just went thru this, and found alarming variance between two $10 digitals I had.  Same model, but different item numbers on them, and they behaved very differently and were each off. 

I have been very happy with the one at the link above.  I got some friends together and bought enough for the discount.   Spot-on out of the box, and very quick response times.   Sometimes you just have to invest in quality equipment. 

Offline Mtnmangh

  • BeerSmith Grandmaster Brewer
  • *****
  • Posts: 139
  • All Grain All the Way!
Re: Thermometer calibration
« Reply #5 on: November 24, 2013, 06:04:21 PM »
You guys are making me nervous about my thermometers and now I feel the need to recheck them.  This is also true because I do custom leather work and use a pretty specific temp for hot molding holsters.  Hmmmmm.  A test is in order.
Drinking: Belgian Golden Strong ale
              Step Up Porter
              Oktoberfest
               Brown IPA

Primary:  Step up Porter

Secondary: nada

Offline mcbeer

  • BeerSmith Apprentice Brewer
  • **
  • Posts: 11
Re: Thermometer calibration
« Reply #6 on: November 25, 2013, 08:43:59 AM »
water boils in my neck of the woods at 209F elevation 1355ft above sea level.

Offline ghwren

  • BeerSmith Master Brewer
  • ****
  • Posts: 83
Re: Thermometer calibration
« Reply #7 on: November 25, 2013, 09:00:55 AM »
So you are saying that when I lived at 7200' and my "lab grade" thermometer showed 223F at boiling there may have been a problem? That was one of several reasons I ended up with a reliable thermometer.

Offline mcbeer

  • BeerSmith Apprentice Brewer
  • **
  • Posts: 11
Re: Thermometer calibration
« Reply #8 on: November 25, 2013, 01:57:50 PM »
yes, it should have read around 198 depending on the barometric pressure at the time

Offline ghwren

  • BeerSmith Master Brewer
  • ****
  • Posts: 83
Re: Thermometer calibration
« Reply #9 on: November 26, 2013, 08:15:05 AM »
Yes, that was the point.

Offline Ellismr

  • BeerSmith Apprentice Brewer
  • **
  • Posts: 24
  • Go Navy
Re: Thermometer calibration
« Reply #10 on: December 03, 2013, 07:06:04 PM »
I use A weld less  on the kettle and a sanitized clip on as a secondary reference.  If they differ by more than a degree or two then there is a problem.

Offline Scott Ickes

  • BeerSmith Grandmaster Brewer
  • *****
  • Posts: 1281
  • Brewing creatively and sharing the results!
Re: Thermometer calibration
« Reply #11 on: December 03, 2013, 07:15:27 PM »
I accidently hand calibrated my thermometer at a club brew day.  We were running 5 different brew systems in my garage/driveway.  I was dipping a pitcher into my strike water and transferring it to my cooler mash tun and went in a little deep with the pitcher and scalded my hand slightly.  Without missing a beat, I looked up at one of my brewfriends who was watching and I said,

"Yup, it's at 163.1 degrees.  Perfect!"

 :D
Kegs:
 Red IPA
 ESB
 Saison Solera
 Dubel (Aged in Malbec Wine Barrel
Aging:
 80 Shilling (In bourbon barrel)
Bottled
 Peppermint Patty Stout
 Wee Heavy

Scott Ickes
https://creativebrewing.wordpress.com

Offline BILLY BREW

  • BeerSmith Grandmaster Brewer
  • *****
  • Posts: 343
  • GOOD BEER GOOD FRIENDS GOOD TIMES
Re: Thermometer calibration
« Reply #12 on: December 07, 2013, 06:38:12 AM »
Now I feel like a piker...Been using a basic meat thermometer for 20 years...Haven't thrown any homebrews away yet...
Retired Home brewing biker Who wouldn't love me?