Author Topic: Accurate thermometer  (Read 2893 times)

Offline BrewQwest

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Re: Accurate thermometer
« Reply #15 on: February 17, 2013, 06:34:00 PM »
.. thanks for the link on the lollipop...I know some fellow brewing friends that will appreciate this...and cheers!!
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Offline mabrungard

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Re: Accurate thermometer
« Reply #16 on: February 17, 2013, 07:02:06 PM »
Disagree on your analysis of freezing and boiling for calibration. It's a well accepted way to calibrate thermometers , considering most do not havens calibration block. The point being, you don't care about the temps of 32 and 210-212, they just provide references on both ends of temperature spectrum so you can establish a calibration curve for your thermometer.

How would you replicate 150f or similar mash temp and know its that temp without a calibration block??

Sorry, but you can't replicate 32F or 212F either without some work.  You cannot rely on actually producing a 32F temperature with water and ice.  The Thermapen website has proof of that.  However, with adequate precautions, it should be close according to that same site.  An important thing with regard to boiling point is that you have to correct for your elevation or you won't properly account for what the temperature is.  Remember that 212F is the BP at sea level.  It changes significantly with increasing elevation. 

As others have alluded, just because you have a match with your thermometer at freezing and boiling, it does not confirm that the linearity of temperature measurement for your instrument will extend through that all-important temperature range we are interested in.  That is why it is still better to find an accurate reference standard to calibrate to in that temperature range.  Its easy enough to add 150F to 180F water into an insulated jug or container and insert the reference and working thermometers.
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Offline wort-h.o.g.

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Re: Accurate thermometer
« Reply #17 on: February 17, 2013, 08:41:54 PM »
My elevation is 210f for boiling. And no, there is no knowing for sure, but it's the best I can do or anyone can do without a calibration block - exactly why the reason I started this thread. Within a degree is the best I can hope for with these tests.

Anyway, apparently nobody can say there mash temps are dead on ( w/o calibration device) and if there thermometer is accurate after months or years of use.

"Its easy enough to add 150F to 180F water into an insulated jug or container and insert the reference and working thermometers."  - Mabrungard, can you explain how you go about doing this... Thanks.
« Last Edit: February 18, 2013, 05:14:57 AM by wort-h.o.g. »

Offline dzlater

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Re: Accurate thermometer
« Reply #18 on: February 18, 2013, 04:41:48 AM »
If anyone else is curious, I was wondering what a "traceable" thermometer was, and found this:
http://www.epa.gov/hg/traceability.htm
On the website it states "user sends the thermometer back to the manufacturer for recalibration after manufacturer's recomended interval"
Do any of you with traceable thermometers send them back for recalibration?

Offline denny

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Re: Accurate thermometer
« Reply #19 on: February 18, 2013, 11:07:19 AM »
My elevation is 210f for boiling. And no, there is no knowing for sure, but it's the best I can do or anyone can do without a calibration block - exactly why the reason I started this thread. Within a degree is the best I can hope for with these tests.

Anyway, apparently nobody can say there mash temps are dead on ( w/o calibration device) and if there thermometer is accurate after months or years of use.

"Its easy enough to add 150F to 180F water into an insulated jug or container and insert the reference and working thermometers."  - Mabrungard, can you explain how you go about doing this... Thanks.

I have personal experience with thermometers that were on at the extremes but off at mash temps.  I finally gave up abd bought a calibration thermo that I use to calibrate my brewing thermos at 150F.
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Offline wort-h.o.g.

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Re: Accurate thermometer
« Reply #20 on: February 18, 2013, 12:48:10 PM »
" I finally gave up and bought a calibration thermo that I use to calibrate my brewing thermos at 150F." -

Denny- can you explain....not sure what you mean by calibration thermo?

Offline denny

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Re: Accurate thermometer
« Reply #21 on: February 18, 2013, 12:53:58 PM »
" I finally gave up and bought a calibration thermo that I use to calibrate my brewing thermos at 150F." -

Denny- can you explain....not sure what you mean by calibration thermo?

It's a tested, calibrated alcohol scientific calibration thermometer.  Requires immersion up to the point you're reading.  I use that to double check my "lollipop", then use the lollipop to calibrate my other thermometers.
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Offline wort-h.o.g.

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Re: Accurate thermometer
« Reply #22 on: February 18, 2013, 12:59:10 PM »
where would you buy one of these calibrated alcohol scientific calibration thermometers - got a brand or link?

Offline denny

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Re: Accurate thermometer
« Reply #23 on: February 18, 2013, 01:03:27 PM »
where would you buy one of these calibrated alcohol scientific calibration thermometers - got a brand or link?

I got mine from William's Brewing many years ago.  I don't think they carry them any more.  Maybe try a scientific supply place.
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Offline denny

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Life begins at 60.....1.060, that is!

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Offline ynotbrusum

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Re: Accurate thermometer
« Reply #26 on: February 18, 2013, 02:52:49 PM »
Denny:

How often do you recalibrate and how far off are your other thermometers, typically?

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Offline wort-h.o.g.

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Re: Accurate thermometer
« Reply #27 on: February 18, 2013, 03:31:21 PM »
yeah my only concern is that one on the link is +-2F....i found some with .5 after i had an idea what i was looking for.

Offline beermo

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Re: Accurate thermometer
« Reply #28 on: February 18, 2013, 03:34:32 PM »
Wow. After reading all those posts I definitely have thermometer envy. I have a cheap $19 from my local HBSS where I got my kit... but ya'll have me thinking I should maybe replace it.

I don't have the funds to get one of those crazy awesome ones... but perhaps the $30 Lollipop would be worth the investment.

Offline fmader

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Re: Accurate thermometer
« Reply #29 on: February 18, 2013, 03:46:57 PM »
I don't have the funds to get one of those crazy awesome ones... but perhaps the $30 Lollipop would be worth the investment.

I hear ya about the funds....That's why I got mine off Amazon with FREE SHIPPING!
Frank