Author Topic: Thermometer check?  (Read 7314 times)

Offline Wildrover

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Thermometer check?
« on: December 29, 2008, 05:23:23 PM »
My wife bought me a digital thermometer for Christmas so I checked it against the good ol 3 dollar analog meat thermometer I've been using and sure enough they are off.  Is there any sure fire way to check which is right and which is wrong?  I know some say put it in boiling water but just because something is boiling doesn't mean it is at 212 it only means it is at least 212? 

Any input would be appreciated. 

Offline Maine Homebrewer

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Re: Thermometer check?
« Reply #1 on: December 29, 2008, 06:05:41 PM »
Ice water is always 32 regardless of the altitude.
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Offline Wildrover

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Re: Thermometer check?
« Reply #2 on: December 29, 2008, 07:47:35 PM »
how much ice compared to how much water?  I have to think it starts to warm from 32 pretty quick?  I also stuck the meat thermometer in the ice chest it went well below 32 degrees

Offline Rep

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Re: Thermometer check?
« Reply #3 on: December 30, 2008, 05:01:04 AM »
how much ice compared to how much water?  I have to think it starts to warm from 32 pretty quick?  I also stuck the meat thermometer in the ice chest it went well below 32 degrees

I do not think it matters much.  Simply crush some ice and add it, with cold water to a container.  Let it sit a bit and test the thermometers.

Offline UselessBrewing

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Re: Thermometer check?
« Reply #4 on: December 31, 2008, 05:56:20 AM »
I always go with a glass bulb thermometer. This tech has been around a long time and is very accurate. You can usually pick them up at the LBS for $10-$15. But if you search the internet, you can find them as cheep as a few bucks (I did).

Both the digital and the meat thermometer are based on same principle. That a liquid changes its volume relative to its temperature. With that in mind both can be prone to problems because they are relying on a mechanical translation of that change. So I ask you, Why not just read a bulb thermometer from the beginning?

Hope this helps

Cheers
Preston
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Offline Wildrover

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Re: Thermometer check?
« Reply #5 on: December 31, 2008, 07:27:01 AM »
I like that thinking, my LBS might not have one, any suggestions as to where online I might pick one up?

Offline sickbrew

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Re: Thermometer check?
« Reply #6 on: January 01, 2009, 10:56:02 AM »
Thermometers can be off throughout their specified range, or more so at one end of the scale than the other.  I'd rather know how accurate it was near my mashing temperatures (that boiling test) than at near freezing.

cheers

Offline UselessBrewing

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Re: Thermometer check?
« Reply #7 on: January 01, 2009, 11:01:41 AM »
Scientific supply store on Ebay is where I got mine.
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Offline MaltLicker

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Re: Thermometer check?
« Reply #8 on: January 01, 2009, 07:14:42 PM »
......  I'd rather know how accurate it was near my mashing temperatures (that boiling test) than at near freezing.
cheers

No kidding.  Does anyone make a thermometer that goes ONLY from 95F to 170F?  Or 140F to 170F in big easy-to-read numbers?  All the fancy thermos for the big pots cover ranges that really don't matter. 

Offline UselessBrewing

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Re: Thermometer check?
« Reply #9 on: January 05, 2009, 10:53:04 AM »
Mine reads single deg increments and if I remember correctly 10 deg C is almost an inch. The entire length is about a foot.
Cheers
Preston
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Offline SOGOAK

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Re: Thermometer check?
« Reply #10 on: January 05, 2009, 01:53:09 PM »
I have heard this before too.  My primary thermo is one of those floating ones you might use in candymaking too.  I got it at a LHBS, it was what my mentor had so I figured it was good  :D

Now I can only wonder.  I am going to dig up one of those dial style ones I have in a misc. box somewhere that never got unpacked when me moved.  That one is also kinda sketchy, but will stay in the grist better.

I think...Mine works pretty well.  Time will tell when I try my first all grain batch.  If my thermo says I'm on, but can't convert starch, then I'll be baffled.  I do have to say that I don't like the way mine is graduated.  Plenty of room between hashes, but when you are handling hot liquid something easier to read would be nice.  Mine is like reading a bouncing hydro...

I'll keep using it until I can't trust it.
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