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Temp Gauge Placement - Vertical smokers?

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Post Mon Apr 02, 2007 6:36 am
Ian Mack well done
well done

Posts: 367
Location: Cornwall, UK

I've read that if possible gauges should be mounted at cooking grate level, so I tried it at the weekend.
I was using our ProQ Frontier, with a water pan and the results I got were not what I expected......
The temps read a lot higher at grill level, I can only assume that this is because the hot air is deflected by the water pan up the sides of the unit. This would mean that I am not getting a true reading of the temp at which my meat is cooking, as it sits in the middle of the grill (I don't have one of those fancy remote gauges).

So is the advice written about temp gauge placement correct?

Post Mon Apr 02, 2007 7:17 am
Grand Scale BBQ Deputy
BBQ Deputy

Posts: 4272
Location: York, PA
No you're reading were correct, temp is temp. There's no faking it. You don't need a remote probe to test that either. Presuming the one you osed is long enough when its reading from the tip it should still be close enough to the center to be accurate. Regardless it is inherent in that design that the bottom will run slightly hotter than the rest simply because that is where the fire is after all.
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Post Mon Apr 02, 2007 9:28 am
rogerja well done
well done

Posts: 2288
Location: Central Ohio
What GS said. You need about a 5-6 inch stem to get across the heat coming up around that water pan. If you mount it just below the grate, you shouldn't have any issues with interferring with your food placement.

Post Mon Apr 02, 2007 12:49 pm
Bob-BQN User avatar
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Posts: 12904
Location: Texas
My goodness if you had the probe sitting directly in the air stream of heat coming right off the fire at the edge of the waterpan you must have pegged the needle on your thermometer. :shock:

One unique thing about the temperatures on the bottom shelf that is different from any other level is there are radical temperature extremes. The air flowing around the waterpan is much hotter than the air inside the rest of the chamber until it has mixed and the heat is distributed conventionally. But the air directly over the waterpan is cooler than other areas in the smoke especially at the beginning of the cook when the water is cool.

By locating the thermometer at "grate level" it also means, as close as possible to where the food is cooking. All smokers and grills have HOT and COLD spots, meaning that the temperature varies across the grate. The Chargriller for example, has a hot spot near the firebox and it is much cooler at the exhaust end (on the left). Having one thermometer at the opposite end from where you are cooking would do little good even if it is mounted at grate level.

Similarly in vertical smokers there is temperature variance from top to bottom. Heat rises, so in most empty smokers the top shelf can be a lot warmer than the bottom…. But depending on the amount of cold steel, water, and meat in the smoker and its placement, the mass can cool the air as it passes over and around which will leave the top shelf cooler than the bottom. Once everything warms the temperature difference can invert.

This is why I feel it is important to have the temperature gauge placement at grate level near the food being cooked, so you have an accurate reading. Just like you didn’t get the expected results with your gauge placed in its most recent position, a gauge located in the lid will read incorrectly for the same reason.

If a long stemmed gauge were used as Roger suggested, I believe it should be shielded to prevent conducted heat along the stem from affecting the reading.
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TX Sandman well done
well done

Posts: 1977
Location: DFW, Texas
Ian Mack wrote:
I've read that if possible gauges should be mounted at cooking grate level, so I tried it at the weekend.


:oops: Guess that was me. Sorry, Ian!

Personally, I use an oven therm right next to the food. I never thought of the hot air making it read hotter at the sides. I guess you need to try a long-stemmed ther, or use an oven therm on the grate and compare readings. Image

I'm anxiously waiting for the ProQ. I want to see this live!

Rob - TX Sandman
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Post Tue Apr 03, 2007 7:51 am
Ian Mack well done
well done

Posts: 367
Location: Cornwall, UK

No problem Rob :lol: (I will accept payment for my trashed gauge in beer) I had to try it some time.
It's just that on most forums, mods to vertical smokers always suggest adding gauges near the cooking grates.
Are people just using normal short stemmed gauges, or are they smarter and use a long stemmed one straight off?
I'm no gauge expert, you may have guessed this already, but even with a Long stemmed/ Candy Gauge, surely the whole stem heats up, unless it is protected with only the tip sticking out. If so, how is it done, without investing in some space rocket technology??

Post Tue Apr 03, 2007 9:23 am
rogerja well done
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Posts: 2288
Location: Central Ohio
Last edited by rogerja on Tue Apr 03, 2007 10:39 am, edited 1 time in total.

Post Tue Apr 03, 2007 10:06 am
Ian Mack well done
well done

Posts: 367
Location: Cornwall, UK

Thanks Roger, I did have a look, interesting stuff.

"You can mount a thermometer in the lid or in the middle cooking section. Some people mount them in both locations. In my opinion, the lid is the best place for a thermometer."

I guess I'll leave the ones on our models where they are, and let the people fit extras if they want to.


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