Thermometer Problems

[Stone]

I've been smoking with the WSM for about 20 years now. I've never been happy with my thermometers. Actually, I've never been happy with thermometers whether for the WMS or otherwise.

For example, I've got a fairly new Therma-Pen instant read and a new Thermo Smoke. The other day, I had a brisket in the oven and the oven temp said it was 350*. One of those little analog oven thermometers said it was about 345*. But my Thermo Smoke said it was only 320*.

I put the analog and the Thermo smoke in my Breville toaster oven, set at 350*. The toaster oven beeped that it reached 350* when the analog said it was only 320* and the Smoke said it was 280*

I guess the only real way to test them is to use boiling water? Because I'm pretty much at sea level and it should be 212*?

 

[Len Dennis]

Yup. When you know the discrepancy against a known value (ie boiling water), then just add/subtract the difference and then you know. Most thermometers that we can buy as consumers are frequently wrong.

I bought a combined thermo/hygrometer. It always reads 1o F higher than room temp. I adjust

 

[Bob Bailey]

I use a lab grade spirit thermometer to check the accuracy of the ones I use when cooking and brewing.

 

[DanHoo]

I was shocked to see the temp swings in my electric oven when I used my TW Smoke.

My TW Smoke is within a couple degrees of the TelTru thermometer on my BGE. The TelTru is adjustable. I've tested it several times in boiling water and it's been spot on.

 

[LMichaels]

When we had our Bosch dual fuel range that oven was rock solid. Set at 350 you got 350 and variance stayed within 20 deg. This piece of junk LG ranges plus or minus 70+ degrees!

 

[Chris Allingham]

Testing Thermometers For Accuracy: Ice Bath Test & Boiling Water Test - The Virtual Weber Bullet

How to test thermometers for accuracy using an ice bath and boiling water, and what to do if your thermometer is inaccurate. Video demo of ice bath included.

www.virtualweberbullet.com

Boiling Point Calculator - The Virtual Weber Bullet

This calculator estimates the boiling point of water using atmospheric pressure and elevation. A must for testing therms in boiling water at high altitude.

www.virtualweberbullet.com

 

[Stone]

If the digital thermometer is accurate using the ice test, do you assume it’s accurate at all temps? Or do you also do the boiling water test?

 

[LMichaels]

Considering what we use them for I trust the boiling water test more

 

[Rick P]

If the digital thermometer is accurate using the ice test, do you assume it’s accurate at all temps? Or do you also do the boiling water test?

I do both.
It's probably not necessary.

 

[DanHoo]

If it's a lid temp thermometer I test it in boiling water, corrected for elevation.

I temp test my meat probes in 130F water, because that's in the target range for rare beef.

 

[LMichaels]

If it's a lid temp thermometer I test it in boiling water, corrected for elevation.

I temp test my meat probes in 130F water, because that's in the target range for rare beef.

But, how do you know it's 130?

 

[DanHoo]

But, how do you know it's 130?

I don't know it's 130, but the consensus indicated it was 130.

Sous vide set to 130F top of pot sealed off with plastic wrap. Left it going for a bit to stabilize.

ThermoWorks Thermapen One is head referee.

Punch a hole in the plastic wrap and measure with TW One. Repeat with thermapen classic and an old thermopro.

When I did this the thermo pro read a degree lower than the TW one and TW classic.

I then plugged probes into my TW Smoke x4 and tested them in a few ways. Most were at or within a degree or two of 130.

One probe was randomly reading high, and I noticed this during one of my cooks which led me to testing them.

I had four good meat probes, and one bad one.

I need to do this again as I have another that I suspect.

I also want to test the meater+ probes as they read low and are slower than the thermoworks smoke probes when I'm cooking with both.

I want to find out if the meater+ meat measurement is accurate or if it is just slow.