The Great Bottle Opener Giveaway

Home Brew Forums > Home Brewing Beer > Equipment/Sanitation > Calibrating bimetallic thermometers

Reply
 
LinkBack Thread Tools
Old 01-15-2008, 06:16 PM   #1
AiredAle
Feedback Score: 0 reviews
Recipes 
 
Join Date: Dec 2006
Posts: 474
Liked 17 Times on 13 Posts

Default Calibrating bimetallic thermometers

I stumbled across this webpage today while looking for something completely different. From time to time on this forum we have threads regarding calibrating dial-type (bimetallic) thermometers. I have always calibrated mine by checking the freezing point, this site claims that's wrong, and has added some comments from thermometer manufacturers to back up his assertions.

He claims these thermometers are only accurate within +/- 20 degrees of the calibration temperature. So if you calibrate at the freezing or boiling point, and want to use the thermometer at mash temperatures, you may have problems.

Interested to know what others think, or have experienced.

http://www.hi-tm.com/Documents/Calib-boil.html

__________________
AiredAle is offline
 
Reply With Quote Quick reply to this message
Old 01-15-2008, 08:17 PM   #2
jdoiv
Feedback Score: 0 reviews
 
jdoiv's Avatar
Recipes 
 
Join Date: Mar 2007
Location: Nashville, TN
Posts: 1,149
Default

Funny, I found a very similar write up the other day that said the same thing. He suggested calibrating your therms with a certified traceable therm for the temps you'll operate at. I just ordered this one from Professional Equipment and plan on using it to calibrate all my therms to it.

__________________
Drinking on the keg: BPA, Brown Ale, Dry Mead, Wee Heavy aged on Oak, CAP
Drinking in the Bottle:
Conditioning:
Fermenting:
Planning:
jdoiv is offline
 
Reply With Quote Quick reply to this message
Old 01-15-2008, 09:45 PM   #3
david_42
Feedback Score: 0 reviews
 
david_42's Avatar
Recipes 
 
Join Date: Oct 2005
Location: Willamina & Oak Grove, Oregon, USA
Posts: 25,648
Liked 131 Times on 124 Posts

Default

I use cheap vodka. When heated, it sits at 172F until all of the alcohol is gone.

__________________

Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"

"I would like to die on Mars, just not on impact." Elon Musk

david_42 is offline
 
Reply With Quote Quick reply to this message
Old 01-15-2008, 10:02 PM   #4
jdoiv
Feedback Score: 0 reviews
 
jdoiv's Avatar
Recipes 
 
Join Date: Mar 2007
Location: Nashville, TN
Posts: 1,149
Default

How can you tell when the alcohol is all gone? How long will it stay at 172?

__________________
Drinking on the keg: BPA, Brown Ale, Dry Mead, Wee Heavy aged on Oak, CAP
Drinking in the Bottle:
Conditioning:
Fermenting:
Planning:
jdoiv is offline
 
Reply With Quote Quick reply to this message
Old 01-16-2008, 12:10 AM   #5
AiredAle
Feedback Score: 0 reviews
Recipes 
 
Join Date: Dec 2006
Posts: 474
Liked 17 Times on 13 Posts

Default

The alcohol boils at 173 F because it is an azeotrope, that is it's boiling off as a mixture of 96% alcohol/4% water. When the alcohol is boiled off, and pure water is left, the boiling point will go up to 212 F. With a 40% alcohol content vodka, you'll need to boil off just about half of your total volume to start kicking up the temp.

To be most accurate, the thermometer should be in the vapor phase, with the alcohol/water azeotrope condensing on it.

Edit: these temps are based on sea level/standard barometric pressure, if your altitude or barometric pressure are much different the boiling points will be lower, normally.

__________________
AiredAle is offline
 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Calibrating Hydrometer in tap water? mkorpal General Techniques 4 06-24-2009 10:31 PM
Calibrating brew pot... tireater Equipment/Sanitation 15 04-26-2009 07:56 AM
Calibrating my Hydrometer TexasSpartan Beginners Beer Brewing Forum 8 04-03-2009 03:02 AM
calibrating my keggle DrugCoder Equipment/Sanitation 4 01-24-2009 10:26 PM
Calibrating a digital thermometer shertz Equipment/Sanitation 1 01-19-2009 03:31 PM