Issue calibrating a dial thermometer...

[stratslinger]

I'm getting my new HLT ready, and just attempted to calibrate my fancy new thermometer from bargainfittings. The only problem is that if I calibrate it so that boiling water reads exactly 100C / 212F (I'm within a couple hundred feet of sea level), then ice water reads about -2.5C / 28F.

Should I just fudge it a bit so that boiling reads a little over, and freezing a little bit under, in the hops that I'll be accurate on my strike temps? Or is there some kind of math I can apply to figure out a correction factor? I'm thinking I'd need at least one other known data point to get such a factor, just not sure how I'd come up with that other known temperature.

 

[lou2row]

Should I just fudge it a bit? I'm thinking I'd need at least one other known data point to get such a factor, just not sure how I'd come up with that other known temperature.

That would be 98.6 degrees.

 

[day_trippr]

Given the choices you offered, I'd calibrate it dead nuts on boiling temperature and call it a day. You're never going to see anything south of ~120°F on brew days with that thermometer (and even that's only if you bother doing protein rests), so there's no sense in cheating towards the ice water temperature side.

If you really want to be OC about it, calibrate it for 152°F against a "known accurate" thermometer, if you have one....

Cheers!

 

[TrubDog]

I had a similar situation and I simply calibrated it to 170 so my strike and sparge water would be correct. Hey - when the water is boiling... It's boiling.

 

[stratslinger]

TrubDog - that idea makes a ton of sense, but how did you go about calibrating it to 170? I don't have any other thermometers that I absolutely know I can trust, so I'm not sure that I can zero anything in quite that well at that temperature. I'm fairly sure I can get close (+/- 1 or 2 F), but that still seems kind of imprecise...