I know that cheaper thermometers ain’t to be trusted. So I bought a thermoworks smoke with 2 probes. Based on their ads, they’re supposed to be within +- 0.1 F.
i also have a Meater, which is also supposed to be accurate.
today, the pit boss smoker says ambient temp is 260, the meater says 218, and the thermo says 247.
who should I believe, and is there any way to calibrate these @#( things?
Ice water and boiling water test for removable probes. Some can be calibrated by you, some have to be sent in, and some are what they are and that's that. Some thermocouples can be calibrated on the user end, some can't. But don't chase that without doing the below or you'll go mad.
HOWEVER, a common mistake pellet.grill.owners do is comparing the grills ambient to a 3rd party ambient probe. You cannot do this unless you either A: Own a MAK with a roaming thermocouple or B: clip the 3rd party probe directly to the grills thermocouple.
Grate temp.will vary widely from your thermocouple depending on its location. Most are in a back.corner, some are in the rear center.
Ideally you would clip a tested 3rd party probe to your thermocouple to verify it reads correctly. Then you would clip your 3rd party probe to the grate and see what you need to set your grill to for the desired temp. You may have to set the grill to 250 to get 225 at the grate or whatever as an example.
Actually, when I was doing the filets the other day, I tested my probe and instant read in the water of the sous vide tank. 125F. Instant read was spot on. Probe was 5* off.
Don't forget that if any thermometer is too close to your protein, it will read low. I'm thinking that the Meater might have been too close to the meat.
Almost all those wireless probes, like Meater, but they're not alone, will have that "problem". It's partly the fog of moisture coming off the protein as Ron mentioned and it's partly the heatsink nature of the probe body stuck inside the protein (at least on some designs). There's not way I've seen to calibrate those wireless probes. I wonder, though not knowledgeable enough, if on some pellet rigs not only is the location usually different from a grate mounted accessory, but do they use some algorithm in their controller to "simulate" or interpret what the temperature might be. Some of the wireless probes work that way.
Large Big Green Egg, Weber Performer Deluxe, Weber Smokey Joe Silver, Fireboard Drive, 3 DigiQs, lots of Thermapens, and too much other stuff to mention.
As others have said, the ambient sensor on wireless probes is accurate, but not a true account of the grate temperature.
It isn’t unusual for two pit probes in different locations on the grate, or even just an inch or so apart, to be off by 13°, or more. I’m pretty fanatic about testing and calibrating my probes; I check them in ice water and in boiling water every spring, keeping in mind that water boils at 209° at 1750’ elevation.
Even with completely accurate probes, I get differences. There are currents and eddies within cookers. There are hot spots. And as charcoal burns, eddies and currents change, and hot spots move.
Bottom line is: 13°, or 20°, doesn’t really matter. Escoffier didn’t have oven thermometers when he invented modern cuisine. Back then they had low oven, medium oven, and hot oven. (I just read the book, that’s why I’m using the reference. Not that we are Escoffier.) Just stay in that range, if you’re shooting for 250°, anywhere from 240° to 265° is going to be pretty much the same. In fact BBQ Guru’s fan/probe system is set up so that it ignores 5° on either side of the set temp; so if you set 250°, when it hits 245° the display jumps to 250°, then stays there unless it goes under 245° or over 255°! That’s just to keep users from “chasing degrees”. 5° one way or the other isn’t important.
Anyhow, yeah, they'll be different. But not necessarily wrong. Just keep it in the range and the food should come out fine.
The probes need to be in THE SAME LOCATION if you are going to compare them like this. A few inches away can make a difference. If you are doing the boiling water test in Long Island you can use 212 F as a benchmark, but you'll need to adjust for altitude if you have some elevation where you are. I think digital thermometers increase concern around pit temperature. The nearly instantaneous readings can make it seem like there are huge variations in ambient temperature, when in fact the pit is relatively stable and varying slightly around the set temperature. The protein temperature cannot change nearly as fast as the ambient air temperature, which is being influenced by the fan on a pellet cooker. I personally don't sweat the minute-to-minute temperature swings, but I know some people want to see a rock-solid pit temperature. If that is you, maybe an analog gauge can save some anguish.
While I was writing my response and double-checking wording due to the two highballs I've had, Mosca posted a much more elegant response. Please read there for a much better description of what I thought I was trying to say.
I’m wondering why the location of he probes should make a difference. After a while, shouldn’t everything be in ‘thermal equilibrium’ and be the same temp?
No it won’t be. Moving air as it is heated and rises, changing hot spots in your charcoal bed, and shielding from the protein are just a few of the variables that come into play. Just check the temp of your cooker on the exterior in a few places and you’ll see a difference.
Especially on a pellet grill, you have airflow that can vary wildly as well as how the heat is being generated and then dispersed (the design of the heat shield, how the fan moves air, then how the vents circulate it and then thermal characteristics of the different metals surrounding the grills thermocouple). The biggest benefit to a pellet grill is that in theory these differences in temp across the grill are consistent and repeatable
smokyYank this might help a little, do note the MAK is one of the most even (left to right, front to back, but each vertical level will vary) grills on the market so you would likely have more obvious temp zones.
Anyway... Grill is set to 225. The thermocouple has been tested as accurate with a 3rd party probe. The thermocouple is in the back left corner of the grill and that area is roughly 220-230 (hard to get a good read with the FLIR and stainless steel). The heat deflector is at 250+, but where the meat is at is 220. If had an ambient probe on the main grate it would probably be at 230.
The hot spot on the left center side of the deflector is an area with a large airflow hole, and then there's an area around the deflector that looks cooler but it's actually the hot spot on my grill as well as most other pellet grills with a heat deflector like this.
The other pic is my cold smoke attachment, the heat shows from the left via the main side vents of the MAK and then even out roughly as you go vertical. There's a in door thermo that reads pretty accurate, but only for the grate on the same level as it is. That spot is one level above where the reticle is shown, in this pic the thermo reads 128 at that level.
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