dome vs. grill temp

John · May 2007

When my last Polder gave up the ghost, I replaced it with an electronic thermometer that has both a meat probe and a grill probe. As I was cooking a butt last night, I noticed a pretty big gap between grill temp and dome temp (as recorded by my Egg dome thermometer), as much as 40 degrees.[p]My hypotheses (in probability order):
- The dome thermometer (calibrated a year ago) is out of whack
- heat rises, and it's just hotter up there (though that seems really unlikely once the temp is stabliized inside)
- the grill probe is close to the meat, and the meat is colder[p]So, I would appreciate it if one of you can clear this up, and if it ends up being the second one, do you have a normal rule of thumb for converting recipes from dome to grill temp?[p]Thanks,[p]J

Celtic Wolf · May 2007

John,[p] stike will give you the big long scientific reason in a few minutes, but heat rises and gets reflexed back. The dome is always 20-30 degrees hotter for quite a bit of time.

fishlessman · May 2007

John,
there is a greater difference in temps at the start of the cook than towards the end. recipes here reflect dome temp unless it is written as grate temps to avoid confusion.

stike · May 2007

Celtic Wolf,
stike doesn't worry about the difference, because dome temps were fine before anyone noted the difference![p]like saying "now that i can monitor my mileage instantaneously, i notice that going up hills i'm only getting 12 mpg, but going down hills it's 90mpg. "[p]i just keep a steady foot on the gas and pay attention to the overall average.[p]
an electric oven set at 250 isn't at 250 either, so why parse the egg's moment by moment temps?

Darnoc · May 2007

stike,
Well stated.Viking or Wolf ranges give oven temps,not bottom or top of the oven.Tmperature is in the middle of the oven.On the Egg we state grill,indirect,raised grid.

stike · May 2007

darnoc,
even aside from top/bottom of the oven... an electric element cycles on and off throughout the cook.[p]if you set it for "250", the element will cycle on, raise the temp ABOVE 250, then turn off, let the oven cool lower than 250, then kick back on again. the graph of temps in an aelectric oven would sorta look like a sine wave that was centered on 250.[p]i begots better things what to worry about.
for example. brand new bottle of patron anejo. i brought it over a friend's house to watch the fight, and we each had a good glassful. in come a coupla party crashers. they put their natrual light 6-pack in the fridge and drained my poor patron.[p]sniff.... i have MAYBE a short glassful left. THAT'S my concern. i'm getting the shakes real bad right now. i could care less about dome vs. grid.[p]boo hoo. signed,
soon-to-be-tequila-less in seattle

Unknown · May 2007

Celtic Wolf, sorry after the last two weeks, could not resist the Name ID.....only hit the back key 3 times typing it..[p]If you cook in the dome, no real problem with what temp is where, unless you stick the chicken with the probe, like TXfest.....LOL.[p]T[p]

Darnoc · May 2007

stike,
I feel for you man big time.Went to a New Years party,brought some Belgum beer and went to the ice chest and found Coors Light and my brew was gone.

BurntRaw · May 2007

stike,[p]Oh man, congratulations![p]"i brought it over a friend's house..."[p]You got a friend! This is outstanding![p]Remember, don't be too clingy and for God's sake DON'T bring out the Polka collection until after the first sleep over!

Big Hoser · May 2007

John,[p]I noticed the same thing this weekend when I broke in my new Maverick ET-73 to cook up some beef ribs. Early on in the cook, the grate temp and the dome temp were within 10-15 degrees of each other, but after a few hours, the dome temp read 290 and the grate temp was 245-250. Like others below have said, I think part of it is all the heat energy that the dome collects and reflects back that your dome temp probe reads. The other part may be in the fuel: I noticed the grate temps would flucuate from a low of 238 to a high of 260, and my theory on that is the temp will spike up when a new piece of lump or wood chunks/chips catch and start going. Fortunately, I've not had a remoter thermometer to monitor the grate temps and so I've learned to trust the Egg and not fiddle with the dampers every time I get a spike in temps, else the Maverick would have set me hopping like a ho on dollar night. I just set for a grate temp alarm range for below 210 and above 260 and relaxed in between mopping the ribs hourly. [p]Dan

BurntRaw · May 2007

John,[p]It's kinda weird, but I got a Tel-Tru thermometer that reads exactly what the Guru reads (with the Guru attached to the grill or grid or what ever you want to call it, of course). So, at least for me, I ain't so sure about this large temp difference.[p]But then again my Egg is possessed, so I may be in the minority here.

fishlessman · May 2007

BurntRaw,
is your teltru the 2.5 inch model, the error on those in the egg gives pretty much the grate temp. its all i use now and accept that it more accuratly gives a grate temp reading being off about 10 to 15 percent in the dome. when cooking in the dome i make a mental adjustment on temps adding 10 percent to the reading. seems to be close enough for whats going on in the egg.

RRP · May 2007

fishlessman,
I use the 5" Tel-Tru and it runs exactly what the Guru says as I clip the Guru clamp to the Tel-Tru tip. BTW I use a 1/2" spacer so it's only 1/2" longer than the BGE thermometer.

BurntRaw · May 2007

fishlessman,
Nope, I got the long one but what you state makes sense.[p]To tell you the truth, I never really give it much thought. I did a brisket Saturday where I just set the guru to 220 and walked away (actually more of a strut) - alarm went off at 190 and it was perfect.

fishlessman · May 2007

RRP,
they should run the same if they are attached together at the tip, the difference comes when folks put the temp probe down low on the grid, lower than the dome gage. the trick is to know whats going on in the cooker, any cooker, then its easier to make the necessary adjustments for what your doing with the setup you have. probes on the lower grid with inderect setups and large pieces of meat can easily be fooled, ive seen readings of less than 200 degrees down there with a fire that could melt bottles happening under the stone.

fishlessman · May 2007

BurntRaw,
after a while there isnt much to think about for temp control, this weekend i cooked a country loin, reverse trex, and some ribs and i didnt even have a way of monitoring egg temps. i had a thermapen to monitor meat temps, but those are useless on dome temps. i just set it all up and trusted things.

tomo · May 2007

John,
I always thought that with a ceramic cooker there would be a time dependance on the temperature differance between the grill and the dome. On a WSM it stays constant about 25 degrees. On a ceramic cooker, I would think that as the walls heat up, the differance would go down as you reach a thermal equilibrium. That's one reason ceramic cookers are so great as they are stable.[p]I've read complaints about how long it takes to decrease the temperature. Again that is because the walls have to cool off. If you want to sear, go up in temperature, sear, and then come down to the desired temperature. Do not allow the walls to heat up....tom

Matanuska · May 2007

John,[p]I've noticed that the dome & grill temperatures can differ by as much as 50 degrees. Which one's hotter depends on whether I'm doing a direct or an indirect (platesetter) cook. The grate is hotter for a direct cook. The dome is usually hotter for an indirect.[p]Anyone else notice this?[p]Matanuska

dome vs. grill temp

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