Calibrating Thermometer

Bob V

All this talk about thermometers had me wondering about mine. I have a BGE thermometer that goes to 700-750 with the nut in the back for adjustment. I remember reading on the forum somewhere that all you do is put the end into boiling water and turn the nut until it is at 212. Is that all there is to it? Does that really make it accurate across the range?[p]Bob V

TRex

Bob V,[p]With most any temperature indicator, accuracy can vary over the total range of measurement. However, calibrating your BGE TI to boiling water will give you an accurate enough reading in the temp range you are really concerned about. I would say that, below 150, the accuracy is questionable, but you won't be cooking at those temps. Above 500, you're either doing pizza or searing steak, so you're more than fine as long as you're accurate within 50 or even 100 degrees or so (I mean, hot is hot). The "low n slow" range is between 200 and 300, and this is the range within which you calibrate your TI - so I would feel comfortable with the accuracy in that range. That leaves the 300 - 500 range. In here, you could be doing direct or indirect cooking, but a 50 degree accuracy window is likely only to mean a longer or shorter cooking time - the offset is not likely to affect the quality of the final product (in my opinion anyway). This is where an internal probe thermometer comes in handy so that you're cooking by internal temp, not time. Uh oh, now we have yet another TI to calibrate! Well, if you use a Polder here, and do the 212 check every now and then, I think you're safe.[p]Was that way too long or what?[p]TRex

Mike in MN

TRex,
Naw, that wasn't too long.[p]I'll add this, I would calibrate that BGE thermometer on a regular basis, especially if you are doing a low n' slow cook where the temp does matter. Mine was never that accurate, and it seemed to go way off when I would do a high temp cook.[p]Stuff it in boiling water and let it stabilize. Don't touch the bottom of the pan. Use a small wrench to hold the adjuster nut, and twist the dial until it reaches 212°. EZ, eh? About a 5 minute process. I do it while Mr. Egg is first heating up.[p]Mike in MN

Science Guy

Bob V,
I agree with the other comments that calibrating in boiling water gives you a reasonably good starting point for cooking in the 200-250 range with one caveat. If the thermometer is working poorly you may be able to calibrate but not have it read accurately even within this narrow range. It's the old saw about a stopped clock being right twice daily. Ideally any temperature calibration, or calibration of any instrument that measures anything for that matter, should be done with at least 2 points and more if you can. Since these analog thermometers don't allow for a high and low setting it makes this difficult. You could at least know how far off you were. With the BGE thermometer, given the scale, it is impracticle to do anything but a single point. It is possible, but pretty inaccurate, to calibrate in oil that you know the smoke point for. Unfortunately, oil smokes before it boils so not only do you stink up your house but you may not learn alot and it can also be dangerous. My advice is to do what many on this forum have done to solve this problem...buy several and test against each other often if you have doubts about the accuracy.