Testing the temperature probes

[RhodeHog]

I cooked some split pork butts last weekend and ran a test on my probes and checking the surface temp compared to the CC WP24 readings.

At CC 255 degree setting with smoke 10 (high smoke does make the temperature more unstable), the Thermopro was registering 260 on the top rack and 290 on the bottom rack. My in-meat probes were 6-10 degrees lower with the CC reader vs the Thermopro.

• I would tend to trust the ThermoPro since it is a dedicated tool that is designed for professional use and understand if CC had to make a compromise solution for a component of a larger product.
• I also know variance in the probe placement could account for the difference so I’m going to test it more in the future.

Just wanted to share my observations to see what others have observed.

[RonB]

The best way to check your probes is to put them in boiling water. And remember that the boiling point for water is 212° at sea level. If you know your elevation, you can look up the boiling point of water for that elevation. I'm a little over 300' above sea level and the bp is ~ 211° F here.

You could also place your probes in ice water and they should read 32° F.

[RhodeHog]

Excellent idea! The whole time I was testing I kept hearing the Mark Twain comment in my mind: A man with one watch always knows what time it is. A man with two watches can never be quite sure.

[Sweaty Paul]

+1 on this. Can also check the freezing point by then putting the probes in ice water to check the other end of the spectrum.

[RhodeHog]

I did chicken breasts tonight and they were pretty in sync. Probably my placement accounted for the discrepancy in the first test.

[bbqLuv]

Thanks for the post. I Traegerized 2 chicken breasts, The grill probe read 165 degrees but that was about 20 degrees off.
Thermapen for the win. Done at 155 degrees.
Time to calibrate or toss the cheap probe and get a real one.

[briano52]

I have a bit of an interest in evaluating temp probes and accuracy. For me, the gold standard is Thermoworks gear. They send you a certificate that shows your controller and probe is tested accurate to +/- 1 degree. Being a skeptical sort of guy, I test them periodically (trust but verify) in both boiling water and ice tests. They all remain spot on.

Ambient Temp Probes in Pellet Grill

Assessing accuracy in pellet grill temp readouts on the device controller is problematic. Over time, I have learned that most pellet grill controllers have algorithms that are skewed according to proprietary designs to minimize user anxiety. For instance, many do not show accurate readings of ambient temps in the cooker. Because pellet grill heat is generated by a fire pot that is regulated by a fan, the fan speed is either off or on. Kinda like your furnace in your home. Heat is either on or off.

This means that the pellet grill will:

• Have a temp that is set on the controller.
• When the temp falls below the set point, by some unknowable number of degrees, the fan comes on and the firepot gets a lot hotter.
• Then, when the temp gets by over the set point, by some unknowable number of degrees, the fan goes off.

If the read out on the controller of the pellet grill accurately reported the fluctuating ambient temps in the controller, users would be stressing and drinking more beer than they already do. So, in the interest of sobriety, and for the good health of pellet pitmasters, the smart controller reads out changes in the ambient temp that are "softened" by the internal computer. This means that the readout on the screen will not show the full and accurate volume of the fluctuations.

Not to worry, what I have also learned is that ambient temp fluctuations, even fairly large ones of 30-40 degrees, don't much affect most smoking. IMHO, it is the average ambient temp over the length of the cook that is more important for managing and predicting the outcome of the cook. So, the pellet grill makers know this and program their ambient temp readouts not to show the most accurate ambient temps and minimize showing actual ambient temp fluctuations shown on the screen.

I discerned this practice of the pellet grill controllers by monitoring ambient temps on three separate brands of pellet grills. This makes the value of my data somewhat limited, but I suspect that toying with the ambient temp readouts is common in the industry.

Placement Location of Temp Probes in the Cooker Greatly Affect Temp Readouts

I have a number of cookers, kettle, vault, pellet, PK, wood fired oven and several gassers. Everyone, aside from the PK, has a thermometer or two. In addition, I have probes, wired and wireless. Lots of opportunity to compare and contrast readouts.

What I have learned is that placement in the cooker is the most important factor that affects the ambient temp readouts, as between the multiple probes in use, (leaving aside the accuracy of you temp measuring equipment). For instance, in a kettle grill, the lid mounted probe will read far hotter than a grate level probe. In my MAK pellet grill the MAK ambient probe is mounted in the back corner of the cooker, almost against the wall. It reads 15-30 degrees cooler than a probe mounted on one the grates, especially so it the grate probe is positioned above the firepot. And the grate mounted probes also vary according to their height and proximity to cold meat.

My KAT vault ambient probes vary readouts with the height of the grate on which they are placed. And I have a door mounted probe that has a long 7" probe. It was reading surprisingly low. I eventually figured that out when I realized that tip of the probe reached to within an inch of the cold meat that I was putting on the same level as the probe. The cold meat was influencing the temp probe.

Naturally, the degree of influence from the meat over the door probe, declines over the length of the cook. This is what caused me to figure out that the meat was affecting the readout on the door mount temp probe. To my embarrassment, it took me about a year of using the KAT vault cooker to figure out why the door probe was reading low, especially in the early stages of the cook. So, to work around that, something had to move. Not wanting to drill another hole in the door, I decided to move the grates. The KAT has many slots for the grates, so it was easy to reconfigure.

How is This Information Useful?

With probes inside your cooker, accuracy will be greatly determined by location, height, proximity to heat source, proximity to cold meat and the flow of hot air in your particular cooker.

The readout on your probes is not the single most important thing in temperature management. But consistency of probe placement and correlation with results cook to cook is ultimately what you need.

For a long time, I fretted over getting my ambient temps to be exactly like I read in the recipe. After a while, I found that is both impossible to achieve and not necessary. Close is good enough on ambient temps to get the cook to be good. Judging when your meat is actually done to your liking is really the most important thing. Aim to have your temp probes in the same place with every cook and to show temps that you can rely on to duplicate results cook to cook.

There are several good ways to measure meat doneness. Temperature is one but a lot of good pitmasters go more by probe. Insert a toothpick or other probe into every meat you cook until you learn exactly how much resistance indicates your preferred level of doneness. There are other methods: finger push, lifting a rib rack and testing for how bendy it is and degree of visible shrink in the meat.

To windup this lengthy post, making your ambient cook temps reliable and repeatable for your cooker will help you turn out a good cook every time. Don't sweat it if your ambient temp readout gear is exactly accurate or not. Just use the same ambient probe in the same place every cook so you can achieve regular, repeatable cook conditions.

[RhodeHog]

Excellent analysis and observations on the result. I agree that one should not agonize over the fluctuations that will get to the target pull temp: like a plane making constant corrections. I too find that tracking temps allows me to more accurately predict how long a cook will take with my equipment and similar conditions. And, like you said, finding the hotter and cooler zones on the smoker is very important.

[Carolyn]

I found this link helpful for accurately testing thermometers using an ice bath. You need a lot of ice in the cup.

https://youtu.be/2OmhRH30KMw?si=Tql7rODc1LI_mucs