Temperature observations

[Kirk A]

The past couple of cooks, I've used a Maverick temperature probe to judge the cooking temperatures. From reading here, I know that the lid temp will often be quite different than the temperature on the rack. I've seen that already, but today's cook I noticed something different.

I cooked two 8lb pork butts on the top grate, between which I put the probe to give me a sense of the temperatures on the grate. The probe was in the middle of the grate, away from the edges, and was about 1/2 inch from each butt. When first coming up to temperature, the Maverick was reading about 225, while the lid was over 270 or so. However, later in the cook, the Maverick was still around 225, and the lid temp was more like 230.

Not sure of what my point is, other than I was surprised to have the delta between the two thermometers be off different amounts at different times during the cook. With the maverick, I feel like my cooking times have been a bit shorter, which makes sense, as previously I had set the lid temp to be close to 225 which now I know would be too cool.

 

[Dustin Dorsey]

I've noticed the same thing. You might have your chamber probe too close to your meat which can lower your reading but you're probably fine.

 

[Kirk A]

That was my guess as to the cause, fascinating to learn more about the science every time the smoker is used.

 

[Tommy B]

yea I would move the ambient probe farter from your meat. especially when that big slab of meat goes on cold or at room temp.

 

[Charlie L]

I've noticed the same thing. You might have your chamber probe too close to your meat which can lower your reading but you're probably fine.

1/2" from meat is close. try to get 2" away to avoid the temp variation caused by hot or cold air coming off meat.

 

[J Hasselberger]

I've noticed the same thing. You might have your chamber probe too close to your meat which can lower your reading but you're probably fine.

Don't do what I did. Doing three coiled racks of spares, I didn't have a good spot to put the probe, so I got clever and clipped it under grate, rather than on top. As soon as it got hit by meat drippings, the temp went up and down like a crazy yo-yo. I think 2" clearance between probe and meat is probably good.

 

[Kirk A]

1/2" from meat is close. try to get 2" away to avoid the temp variation caused by hot or cold air coming off meat.

Great idea, though not sure how it is possible with 2 butts on an 18, but I'll keep it in mind.

 

[Craig Alumbaugh]

I can agree with moving your probe a little father away. I usually clip my probe to the bottom of the top grate and my temp seems to be where I want it.

 

[Charlie L]

Great idea, though not sure how it is possible with 2 butts on an 18, but I'll keep it in mind.

Sorry i misread your OP i thought it was a 22. I think i once saw a post who would use alagater clips on probe and would clip on a wood skewer stuck into meat. You might be able to do the same with a foil ball. poke skewer though foil ball and stick in meat with foil ball hanging off skewer and then poke probe through. So the probe is hanging off the meat at the desired distance.

 

[Bob Bass]

I place my Stoker's pit probe where Harry Soo does his. Took a close look at his while taking his class a few years ago.
Since I want to control the temperature being delivered to the 'cooking area', my pit probe measures the air temperature just BEFORE it hits that area.
Installed a grommet, from Rock's BBQ, in place of one of the screws for the upper cooking grate hangers. My pit probe sits inside this grommet with about 1" to 1 1/4" of the probe just inside the WSM.
It is in the "hot" spot, if you will. But that IS the temperature being delivered to the cooking area. And it is the temperature I am trying to control.

 

[Vincent Carrocci]

It is in the "hot" spot, if you will. But that IS the temperature being delivered to the cooking area. And it is the temperature I am trying to control.

Sorry Bob, I totally disagree with you. The temperature of the air rising around the inner circumference of the the cooker, (the "updraft"), is not the same as the temperature of the air when it hits grate level. My experience has taught me that the best place to measure the temperature in the cooker is about 1-2" above the grate and about 3" in from the side. As has been mentioned above, putting the probe too close to the meat will give a false reading, especially if the meat is cold and has just been placed on the grate.

 

[Bob Bass]

Vince,

I believe we are measuring in basically the same area. Your probe tip is probably only 2" - 4" away from mine. Mine is just below the upper grate and 1" - 1 1/4" inside the WSM. Harry got me going on that location and it compares well with similar work I did for so many years in the industrial process control arena. What does make this 'hobby' interesting is the many methods and adaptations we use to (hopefully) arrive at the same goal.

I also run dry... no water.

My best to you. Great to see you on the forum !

Bob

 

[Vincent Carrocci]

In my experience, those 2"-4" makes for a very different set of numbers. That having been said, do what works best for your style.

 

[JRAiona]

I can agree with moving your probe a little father away. I usually clip my probe to the bottom of the top grate and my temp seems to be where I want it.

I'm in the same camp as Craig. I clip my probe underneath the grate being sure it is placed where meat drippings wont hit it.

 

[Charlie L]

In my experience, those 2"-4" makes for a very different set of numbers. That having been said, do what works best for your style.

That's really all there is to it. We all do what works for us.

I think Vince has a point that the "updraft" isn't the "true" grate temp however i think one reason harry and bob use that is that its more of a constant with less variables. The updraft really only being affected by lit fuel and air and less by cold meat, grate position, water pan etc. This might really be more of a benefit if you are using an ATC, which harry does. Your controller probe in the outer position will be measuring the heat being sent to the meat, not the heat that's actually getting there.Its kind of like you're measuring heat input not output (not sure if that makes sense).

At the end of the day its semantics. These numbers are strictly for example but if Harry wants his grate temp to be 260 he might set his atc at 275 knowing that his probe in the hot zone is 15 degrees higher then where the meat is. i guarantee someone who does as many cooks as he does knows the variations like the back of his hand.

Either works and i usually measure how vince does, but this post definitely makes me want to experiment with the other method with my pitmaster iq and my mavericks.

 

[Brian Cross]

I put my probe in the grommet from the factory with about 2 inches inside. In my low tech testing running my smoker 250 to 270 at this point gives me 230 to 250 or so where the meat sets. Dome temp 230 to 250 is about what I see when my smoker but all these gauges in the lid run different I'm sure. I don't want anyone on here to think I know what I'm doing but this is what I'm seeing when my smoker is running where I want it to. At these temps my cooking times are about right. I always start with the can in the middle using about 8 to 10 lit briquets.

 

[Andy Erickson]

I've put a probe on the grate about four inches inside to test against the stock lid thermostat. Maybe I've gotten lucky, but the two readings are usually within 5 to 10 degrees of each other. That is good enough for me and I will probably not test it any further and just stick with the lid reading.

 

[J Hasselberger]

I think Vince has a point that the "updraft" isn't the "true" grate temp however i think one reason harry and bob use that is that its more of a constant with less variables. T

I think that is the key point -- consistency. If I don't put the probe in exactly the same place for each cook, I'm not really sure if I'm cooking hotter or cooler from cook to cook. Having a fixed probe location is the best way to maintain consistency.

 

[Mike Cout]

I've put a probe on the grate about four inches inside to test against the stock lid thermostat. Maybe I've gotten lucky, but the two readings are usually within 5 to 10 degrees of each other. That is good enough for me and I will probably not test it any further and just stick with the lid reading.

The problem with the bimetallic thermometers is that they can go out of calibration fairly quickly. While your therms might show similar now, you'll have no way of knowing if your dome thermometer starts getting inaccurate.

 

[Andy Erickson]

The problem with the bimetallic thermometers is that they can go out of calibration fairly quickly. While your therms might show similar now, you'll have no way of knowing if your dome thermometer starts getting inaccurate.

Guess I can always test it every now and then. I just hate running wires everywhere. I like to keep it simple. But everybody is different. I don't need to know the exact temp at all times. I just need to make sure I'm in the ballpark so to speak.