Temperature Diff

PatrickJ117 · October 2017

Those of you who "warned" me about Egg and then the subsequent toy costs are right! But it is a lot of fun...and we all have toys, right?

I initially bought the Thermoworks Smoke temp monitoring system. However, I suck at keeping the temp consistent. So just got the BBQ Guru DigiQ. Tried it out on a direct cook art 350, then 375.

The DigiQ temp probe is an alligator clip that attaches to the grill. I set that up, but also set up my Smoke pit temp probe. That is mounted above the grill...assuming it measure the temp of the air.

At lower heat, the two are within 6 degrees---Q hotter read. However, as I got up to 350-400 (that even got away for a while!) the diff is in the 30+ degree range.

My guess is the diff is due to the grill temp vs air? Or am I off the mark here.

Which is the truer measure of pit temp?

Grazie

gdenby · October 2017

This is a common question. Let me sketch out the situation.

Direct and indirect cooks are quite different. Direct cooks expose the food to the IR coming off the lump. That disapates by the inverse square, so moving up closer to the dome markedly reduces the heat the bottom of the food is getting. But it is still really intense. Think of driving in an air conditioned car. Despite the air being cool, if your arm is in the sunlight, it will still get burned.

With indirect, the cooking is all by air temperature. Since hot air rises, the dome temperature at first is usually a good bit hotter than the grill level. 25 degrees is not uncommon. As the cooking progresses, the ceramics absorb heat, and re-radiate it. The food begins to warm up. Typically after a few hours of lo-n-slo, the grill and dome are about the same.

If a platesetter is used for the heat block, it will eventually absorb so much IR that it will reach well above 450F, and the bottom of the food will start getting somewhat hotter than the top.

While everyone wants to cook exactly, with time most people realize that anything 25 degrees+/- of a target temp is accurate enough.

PatrickJ117 · October 2017

I get it. However, the Smoke read was well off the Q---so you're saying even though the Smoke probe was 1 inch or so above the grill, that diff is the other probe bing in contact with the metal vs air temp?

lousubcap · October 2017

There are thermal gradients inside the BGE just like your kitchen clock box. You can get deep into information overload with monitoring temperatures and self-wrestling with what's the right reading. I would sort out one calibrated instrument and go with it. Learn how your BGE responds to that indication and have fun. I use the dome thermo as that is the one thermo all BGE's have.
BTW-around here the generally accepted convention is that if a cook temperature is listed (without any modifiers) then it is dome. FWIW-

saluki2007 · October 2017

How long did you it go at 400? As you increase your temps the ceramic is going to absorb more heat until it reaches the same temp as the air inside. If you are placing our probe on top, then it will take a while before it reaches the same temp as the one on the grate. If you dangled the probe just inside the top it would have been much closer to the temp on the grid.

CanDid · October 2017

@PatrickJ117- I'm not sure they understood the probes were a couple inches apart. @gdenby was referring to dome temp vs grill temp I think.

Having a 30 degree difference so close together may have to do with one probe being in a more direct line of heat than the other (one on the edge of the plate-setter and the other probe completely over the PS) or possible the alligator clip reads much hotter because it is getting heat transfer from the metal it is touching. In that case you may want to try the probe tree below.

Image: https://us.v-cdn.net/5017260/uploads/editor/ai/ndzd4lctg4n9.png

gdenby · October 2017

My experience with a Maverick system on the grill was even more drastic than dome vs. grill. When the probe was near the food, the probe temp might read 50 degrees cooler before the meat warmed up and evaporated away lots of cool water. A couple of times I happened to put the probe over a lump hot spot, and it read 50 + degrees higher.

PatrickJ117 · October 2017

Thanks for all the input.

i tried another direct burn yesterday...this time I placed the Smoke probe immediately next to the Q alligator clip...they were within a few degrees of each other...took the heat from 325 to 350 to 375 to 400...the Q responded perfectly and both probes worked fine.

Re: why use 2---the Smoke allows me to have the wifi that I can take indoors ...and is a double check. Might have just gone with the Q originally but ...it works fine for me now.

Next an indirect heat up today to see how that goes...then will use the BGE for a longer cook on Sat getting ready for the Yankees game.

Thanks again to all for the help for this rookie.

Temperature Diff

Comments

Categories