So I have to ask who has submersible thermometer they can substantiate maintains an accurate temp?
Mash temp and water temps are so critical…what can you trust and how do you verify it periodically ?
I’ve used 3 different thermometers and get 3 different readings…2 are about 1.5 degree apart and the other is 4’degrees higher.
It’s not submersible but I use a thermapen and highly recommend it. It’s pricey but you can use it for cooking, BBQing, and brewing. Wouldn’t leave home without it!
If you really want to be sure, buy a digital thermometer that you can calibrate and get a lab certified glass thermometer to calibrate it with. I don’t do that though. I use this…
http://www.amazon.com/Taylor-Professional-9306-Thermocouple-Thermometer/dp/B000XS7WTG/ref=sr_1_9?s=home-garden&ie=UTF8&qid=1360901097&sr=1-9&keywords=taylor+instant+read+thermometer
It and the Thermapen are splash proof, but not waterproof.
At work we have a NIST-traceable calibration block that is used to cal all the thermometers used at work, so I can check mine in that block.
But that’s a pain 
so I just got one of these:
$30 for a waterproof nist-accurate 10" probe lolipop thermometer. works great.
I read one of these threads a while back, EVERYONE recommended Thermapen. So I got one…Done deal! Never looked back.
PS i got the pink one
I have some of the devices mentioned, but the issue is they all are different. That begs the question, which is correct?
I guess I will have to run a controlled test- melted ice in a glass to create freezing temp of 32f, and boiling water at 210f at my elevation, then compare each devices readings in the freezing and boiling points.
You should also check what they’re all reading at 150 or so.
“You should also check what they’re all reading at 150 or so.”
Can’t really replicate 150f. That’s why you measure 32 and boiling point temps as a calibration measurement.
I use the ThermoWorks RT600C: http://www.thermoworks.com/products/low_cost/rt600c.html
Works VERY fast (3-4 seconds) and costs 25% of the Thermapen. Mine is accurate within 1.2*.
FWIW I have the previously posted $30 lollipop NIST-traced thermometer, alongside a bimetal. I feel that my temp acccuracy has improved dramatically. Used the lollipop for the 1st time on my current batch on tap (an APA) , mashed @ 152, and I love the beer . I think the accuracy is there. $30 very well spent.
Except that you don’t care whether your thermo is accurate at freezing or boiling. The mash temp range is what you care about, hence calibrating it around 150. Just because your thermo is accurate at freezing and/or boiling (real fun getting both ), means nothing about it’s accuracy around mash temps.
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??
+1 to the 150F… we don’t mash at freezing (is the slush supposed to be 32 or is the frozen water supposed to be 32 or is 32 somewhere within a degree or two different) and we don’t mash at boiling (is 210 actually boiling at your elevation utilizing your brewing gear or is it a degree or two different)? And with only one thermometer, how do you verify its accuracy when you do get to mash temps?
I now standardize on an RTD probe (+/- 1%) hooked to a PID previously calibrated with a lab thermometer. Prior to this I ran a digital thermometer, stem thermometer, and a submersible thermometer at mash temps while heating up some water… Make up a chart of any differences in any of the readings at any temp between them… cheers!!
+1
+2
… thanks for the link on the lollipop…I know some fellow brewing friends that will appreciate this…and cheers!!
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.
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.
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?
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.