Question about calibrating a thermo

[mranum]

This might seem like a stupid question but, water boils at 210* but is that boiling point considered just the start of bubbles? I mean a rolling boil is way hotter than 210 correct?

[MilitantSquatter]

you want a rolling, aggressive boil with steam.. the small bubbles earlier at the bottom are just air pockets but it's not at full temp yet.

at sea level it's 212 deg. and approx a 2 degree drop in temp for every 1K feet in altitude above sea level.

hope that helps !!

[Saiko]

Most important is to make sure you compensate for your elevation, as the higher you go, the lower the temperature that water boils. This website has a little calculator for determining the boiling temp of water at your elevation:
http://www.nakedwhiz.com/ceramicfaq.htm#calibrate

Don't worry about barometric pressure, it has a very small affect and not worth even plugging in. As far as when to measure, just wait till a full rolling boil, I mean you are talking about a couple of minutes, so no biggy.

Edit: A quick search, and according to wikipedia, your elevation is 1027 feet, which means that water boils at 209.6 (rounded to 210) at your elevation.

[mranum]

Ok thanks guys, I guess I'll have to check it again. Seems when I checked it before it was just bubbling good but not rolling at all and read about 212*. But I better check it again just to be sure where I'm at.

[ABQ]

An alternative would be to use extreme cold to calibrate a thermometer. Fill a container with ice, add water, stir, add thermometer count to 30 and calibrate to 32*.

[voodooblu]

ABQ is right... the best and most accurate way is ice water!!

[Crazy Harry]

calibrate it at both ends to make sure it is tracking properly. for cooking, the upper end is more important; for food storage, the low end.

[Kettledog]

Two point calibration is more desirable but if you're using it for cooking temps mostly, the calibration point closest to your actual measurement (boiling point) is more important.

[mranum]

The thermo in question is a turkey fryer thermo that sits under the grate on my uds and the lowest temp on it is 100*.

I never heard of the cold water calibration, I will have to remember that.

[baldbill]

Go with the icewater bath method. More accurate and safer!

[Saiko]

Sorry, have to disagree about the icewater method. When doing a one point cal (which is by far the most common), you want to calibrate at the temperature nearest to the temperature that you will be measuring, which is anywhere from 140 degrees to 210 degrees. Water boils at around 210, so it is perfect.

The problem with a one point cal is you can have drift, and while you may be rock solid accurate at 32 degrees, by the time you get up to 200 degrees you may have drifted quite far off target. Not all temperature gauges support a two point cal (I don't even know of one that does, but I'm sure they are out there). So if you're stuck with a one point cal, the higher temp makes much more sense to me. I could be wrong, maybe someone with a physics background can chime in here.