Thermometer Temps and how to proceed?

[DFoster]

I have smoked 3-4 times on my new FatStack smoker without using my ThermoWorks Smoke thermometer. I just went off the Tel Tru Thermometers on my rig. I wanted to gather some data on my second brisket cook since my first one was probably one of the worst briskets I have done (first one on the offset). What I noticed was my Tel Tru Thermometers were reading 50 degrees lower than what my grate temp probe of my ThermoWorks Smoke, so I thought well that’s why I dried the crap out of my first brisket cause I was actually 50 degrees hotter than what my Tel Tru gauges were showing. I decided to calibrate all three (on right by the firebox, middle of smoker and one by the smoke stack at grate level for all) of the Tel Tru thermometers to the ThermoWorks Smoke Grate probe. The brisket turned out good. The flat was a little dry, but I will chalk that up to not trusting my feel and going off of the probe in the meat. .

I placed the grate probe within inches of the Tel Tru gauges and calibrated them. Prior to doing this, the middle of my smoker was running 25 degrees hotter than the other two gauges, but after calibrating them to my ThermoWorks probe they were as expected. If the firebox side read 275 then the middle read 270 and the smoke stack side read 265. After the cook I decided to check the accuracy of my ThermoWorks probe and Tel Tru gauges by using boiling water. The ThermoWorks Grate Probe was spot on at 212. I fine tuned the tel tru thermometers cause they were off by 2-5 degrees. Now here comes the issue.......

I placed the Tel Tru’s back on and started using just the Tel Tru cause that’s eventually where I want to be at. I am a minimalist, so if I don’t have to have redundancy then I am happier with it. About 30 minutes into the cook I noticed that I had that hot spot in the middle of my smoker again reading 25 degrees hotter than the two ends. I decided to get the ThermoWorks probe out to see. Sure enough the tel tru and ThermoWorks are off again. Not sure if I messed up the calibration while wrenching the gauges in the smoker. Here is what I have for the data:

Firebox side: 283ish Tel Tru Gauge/ 295 ThermoWorks Grate Probe
Middle: 277ish Tel Tru/ 294 ThermoWorks
Smoke Stack side: 270 Tel Tru/ 291 ThermoWorks

With that info, should I just calibrate the Tel Tru to the ThermoWorks or leave them since I calibrated them with the boiling water? How should I move forward?

 

[SmoothBoarBBQ]

I think you "wrenching in" the Tel-Tru's is throwing off their calibration. Can you zero them (or calibrate) them while they are still screwed into the cooker? This way you can get them set very close to what your Thermoworks probe is saying without having to "wrench them" in and out which usually screws up the calibration.

I did this with my River Country bi-metal thermometers and even after over a year they were still within just a couple of degrees of what the Thermoworks probe was showing. While this is more of a "zeroing" type action rather than one of calibration, it makes more sense to me because I only care what the temps are inside the cooker.

Before you go doing this though fire up the smoker and get everything nice and hot...maybe run it for 2-3 hours at 250-275.

 

[DFoster]

I think you "wrenching in" the Tel-Tru's is throwing off their calibration. Can you zero them (or calibrate) them while they are still screwed into the cooker? This way you can get them set very close to what your Thermoworks probe is saying without having to "wrench them" in and out which usually screws up the calibration.

I did this with my River Country bi-metal thermometers and even after over a year they were still within just a couple of degrees of what the Thermoworks probe was showing. While this is more of a "zeroing" type action rather than one of calibration, it makes more sense to me because I only care what the temps are inside the cooker.

Before you go doing this though fire up the smoker and get everything nice and hot...maybe run it for 2-3 hours at 250-275.

Ya that’s what I originally did. I think that’s what I am going to do or else I have to deal with my OCD of the gauges not being perfectly set straight up and down or the other way to not wrench them down leaves them too loose in my opinion for when I am taking it down the road.

 

[ruger35]

Should never wrench down on instrumentation like that. Anything like that should be done with a crescent wrench also. I'd actually replace one of them with a new one. Carefully calibrate it then replace them one by one because those instruments can be pretty delicate regarding the internals.

 

[DFoster]

Should never wrench down on instrumentation like that. Anything like that should be done with a crescent wrench also. I'd actually replace one of them with a new one. Carefully calibrate it then replace them one by one because those instruments can be pretty delicate regarding the internals.

I used a crescent wrench. I should clarify they when I say I wrenched down on it, I mean my OCD kicked in and I tightened it to where the gauge was lined up perfectly (I literally took a measuring tape out to get it lined up top to bottom) with the 300 degree and the Fahrenheit symbol were perfectly straight. I used the nut on the backside of the gauge to tighten them down, but a couple of them were completely upside down just prior to getting tight, so I used a little bit of muscle (not a ton) to get half a revolution in.

 

[dummy que]

how far into the pit where your themoworks probes your tru tel read 4 inches from the edge of the grate if your other probe is in the center they will read diff.

 

[ebijack]

I'd suggest you use the gauges as reference only. Don't worry about hot spots. Let the smoker show you where the hot spots are for each cook. Depending on what and how much meat you have on the grates. How the smoker is loaded will change the air flow around and thru the smoker. For every cook. Move the meats around as required to get even cooking.
The more gauges/probes you have. The more they will drive you nuts trying to get every cook where temps are completely even across the grates.
Use the palm of your hand over the smoke stack to gauge temps within 50* or less. This works no matter the cooker.
It is supposed to be fun, enjoyable and fulfilling.

 

[dummy que]

watch ben langs you tube on exsplaning the dif. between pit temp and grate temp

 

[DFoster]

how far into the pit where your themoworks probes your tru tel read 4 inches from the edge of the grate if your other probe is in the center they will read diff.

I had the ThermoWorks Grate probe within 2-3 inches of the Tel Tru.