Thermometer issues, Do I have to worry?

joe719 · November 24, 2013, 7:21pm

I bought my HLT and Mash Tun with Fermentap thermometers. The HLT has a 2 inch thermometer and the other a 6 inch. I wanted to calibrate them so I made an ice water bath and boiled some water. At boil both thermometers read 210 in the ice bath the long meter read 36 and the short 39. So my question is, is the difference in readings enough to worry about? 3 degrees. I know there is usually some variance in the instructions for strike water temp and mashing temp. I just don’t know if I should adjust them to read the same and if I dial them both to 212 at boil are they going to be further apart in ice. Is this is a case where close is okay.

Thanks in advance,
Joe

nighthawk · November 24, 2013, 7:55pm

Will you be able to tell the difference between a beer mashed at 150* verses 153*? Only you can answer that question.

Find a system that works for you.

surly · November 26, 2013, 5:12am

You seem to be the type of person that likes to calibrate and be accurate in your procedures.

I would say, get a third thermometer and check yours against it and make the individual adjustments on the thermometers that you need to make to get the consistency you desire.

Yes, wort made at 150F will taste good when it becomes beer.
Yes, wort made at 153F will taste good when it becomes beer.

But if you are looking at consistency from beer to beer, certain types of mouth feel then by all means calibrate doing the best you can.

ynotbrusum · November 27, 2013, 2:05am

Consider a Thermapen at some point. I don’t trust my mounted thermometers (all are Blichmann BTW) and I have found hot spots in the mash when not thoroughly stirred. I wouldn’t have caught that with a mounted thermometer.

joe719 · November 27, 2013, 11:49am

Thanks for the info guys. I like the idea of the Thermopen just to be certain.

donovan_lambright · November 30, 2013, 2:06pm

Bit late to the conversation but I seem to recall reading somewhere that it’s uncommon to get some thermometers equally accurate at freezing and boiling temps. Therefore, it’s most important to get them calibrated at the hot end (since that’s where you are using them).

Maybe that’s only true of cheaper thermometers, though.

beerme11 · December 2, 2013, 10:36pm

[quote=“Joe719”]I bought my HLT and Mash Tun with Fermentap thermometers. The HLT has a 2 inch thermometer and the other a 6 inch. I wanted to calibrate them so I made an ice water bath and boiled some water. At boil both thermometers read 210 in the ice bath the long meter read 36 and the short 39. So my question is, is the difference in readings enough to worry about? 3 degrees. I know there is usually some variance in the instructions for strike water temp and mashing temp. I just don’t know if I should adjust them to read the same and if I dial them both to 212 at boil are they going to be further apart in ice. Is this is a case where close is okay.

Thanks in advance,
Joe[/quote]

There proper way to make an ice bath according to the thermopen manual is to fill a large glass with crushed ice then add cold water until it reaches ~1/2" below the top of the ice. *If the ice floats up off the bottom of the glass the temp is likely warmer than 32F. Insert probe 2" into the mixture and gently stir while taking reading. Depending on where you live water may not boil at 212.

chinaski · December 3, 2013, 1:44am

3F isn’t worth stressing over. If you’ve got 2 thermometers that are that close then you should be set. Adding a third measurement doesn’t necessarily tell you accuracy of any of them any more than using two. At some point you have to have faith that they are accurate enough & without a laboratory grade, calibrated thermometer you’ll never know for sure.