Grill and dome temp difference

Gwei-lo

Is there any such thing as a reasonable estimate for the difference between dome and grill temps, assuming no heat deflectors or firebricks are in use i.e. just the main grid and nothing else? If so, what is it? Thanks for any help.

Nature Boy

Gwei-lo,
You probably won't find much difference in the temps during direct cooking. With heat deflectors and ceramic mass it all depends on your setup, but a 25 degree difference is very common with indirect setups. I have measured up to an 80 degree difference with a platesetter/drip pan setup and a load of meat. The differences can be especially high if you use liquids in your drip pan.[p]When cooking direct, there should be little if any difference, and it is simpler to achieve consistent results.[p]Hope it helps. What's cookin? [p]I am thinking about getting some meat out of the freezer for later. Hmm. Maybe some steak after seeing Darryls pics!
Cheers
Chris

Tim M

Gwei-lo,[p]I agree with Nature Boy. I did a test a few years ago with 6-7 Polder probes in various locations and heights above the grid while cooking ribs directly. The temps were only 5-10 deg apart after the dome is closed and allowed to equalize for 10-15 minutes. I noticed that if I removed the tight retriction at the chimney (I used a slide daisy top) and went with the open chimney and adjusted the bottom vent, then the temps would not equalize in the cooker and you had some big variations in temps. That is why I advocate using a chimney top and controlling temps from above rather than from the vent below. [p]Indirect cooking does give some wild variations in temps and bumping up the dome temp by 50 deg more than compensates for it.[p]Tim

Vogs

Gwei-lo,
I have also noticed that the grill and dome temp variation will change over time on long cooks. As time goes on the temperature variations seems to decrease. Probably because the heat deflector, water pan and meat temperature keep rising. [p]Vogs

Gwei-lo

Tim M,[p]Quick question. What's a chimney top?

Tim M

<p />Gwei-lo,[p]The chimney top is what ever you place on the chimney to adjust the dome temps with. Here is a picture of the slide-daisy and how you rotate it so that it won't change its setting when the dome is opened up.[p]Tim

Gwei-lo

Tim M,[p]Gotcha. Thanks mate BTW, great site. I spent quite a bit of time perusing it before buying a BGE, and anticipate that I will be constantly checking back as I get the hang of my new Egg

Banker John

Tim M,
When you say, adjust temps with the chimney (I have a slide daisy), how much should the bottom vent remain open?[p]I have a medium. I usually have only had the bottom open about 1/4" for temps in the 220-250 range, with the daisy slide closed but holes open. Should I open the bottom more and close off the holes up top a little more?[p]I know there is no magic answer to the air flow questions. Just asking you to share your experience. Over time, I will build on my experiences too.[p]Thanks.[p]Banker John

Tim M

Banker John,[p]You can open the bottom about all the way if you want. Think of the cooker as a tunnel - one way in, one way out. You plug up one end and air doesn't move thru easily. The slide tops leak a little, even when shut full, and if you need less temp then start shutting down bottom vent.[p]There are many ways to obtain a desired dome temp - use the method you find works for you. Some don't use a chimney top at all, some use the wooden disks with a hole in it, some use a firebrick on the chimney. There is no best way or only way. [p]Tim

WooDoggies

Banker John,[p]I heard Nature Boy put it this way once and have found it to be an easy to remember rule of thumb...
"Use the bottom vent to find your general temp and your daisy wheel to fine tune it."[p]This has always worked well for me, especially at lower temps. Hope this helps![p]John