Internal airflow/convection disruption and Temperature Control

Chumly · May 2012

Not sure if I am having problems, or if I am just being
impatient, or other.

I made a home made indirect setup and im not sure if by messing with internal air flow if Ive caused my egg to be unstable....

Tonight I made my first actual cook with my newly acquired
Small BGE. I did a spatchcock chicken. I started by lighting some coals and
topping off the charcoal to about an inch or so above the seam of the firebox
and ring. I inserted my home made
indirect setup consisting of:

Placing a grate on to the fire ring . Then I put an 8” pie plate on top of that first grate for drippings and heat
deflection. I then made a few tin foil balls to raise the cooking grid to the
felt line. I placed my cooking grate on top of the tin foil balls and it sat at the felt line. Additionally I added some tinfoil ends to my top cooking grate (creating
an open rectangular middle on the top grate). Now, I had a completely indirect cooking grid, however
different sections of the cooking area were difused at different grate levels. The sides were diffused with foil on the top grid and the middle diffused with
a drip pan on the bottom grid, I THINK that allowed enough air flow.

I got everything up to 400 degrees figuring my cold chicken
would bring everything down to the 350-375 range. I let it sit there for 15
minutes or so while I prepped my bird, then I opened the egg up put the bird in
and got the lid shut pretty quickly. My Daisy wheel lost adjustment so I
eyeballed it back; I also backed the bottom damped back about 1/8^th of
an inch because my desired cooking temp was right at 375 not 400. Now, at first everything
was great. It all held a just under 375 for the first half hour, and then it
started dropping, and I started opening vents up, but still, it kept dropping. (The
fire was absolutely NOT out) Eventually I got frustrated and decided there wasn’t
much time left in the cook and decided to heck with it and I opened everything up until it
finally inched up. However my nice clear almost non existent smoke became a bit
polluted from my vent fiddling, but that is another story all together.

So did I choke my egg with my home made indirect
contraption? Or did I probably just set the dampers wrong when I lost
adjustment when the lid was opened? The part that puzzles me is it was rock
steady for 30 minutes.

Shiff · May 2012

It's possible that some small pieces of charcoal clogged the holes in your fire grate blocking the airflow to the fire. Make or buy a wiggle rod and insert it into the bottom vent and poke it up through the fire grate holes to see if that helps.

You can buy a good wiggle rod at: http://thirdeyebbq.com/WiggleRods.aspx
or make one out of an old coat hanger.

R2Egg2Q · May 2012

A picture would help to see your set up but I suspect this is a big part of the problem:
"Additionally I added some tinfoil ends to my top cooking grate (creating
an open rectangular middle on the top grate). "

as it sounds like you restricted airflow to a rectangle and when you put the chicken on top of the rectangle it blocked off most of your airflow.

If you're concerned that parts of your chicken are getting too much direct heat you could put a little foil under those parts yet still allow airflow up the sides of the Egg.

Chumly · May 2012

Thanks everyone. I appreciate you taking the time to read my long winded problem description! As for pictures, as soon as I took my setup apart to clean it and disposed of the foil I thought to myself " I really should have taken a picture, because this will be difficult to picture." So... my bad on that one. Im thinking my grate became clogged, and I dont think my indirect setup helped anyhting at all. However,I did have a pretty posotive pressure and draft going the Whole cook.

Im not sure what happened, but Im confident that it was my fault. So I guess Ill just have to make a wiggle rod, and redesign my indirect setup (until I can locate a platesetter locally) and give it another shot.

(FYI The chicken still came out delicious and moist despite my troubles.)

lousubcap · May 2012

I don't own a SBGE but have read that it is the most problematic when it comes to getting to and maintaining high temps-many have gone witha high-que fire grate that suposedly makes a noticeable difference-

You may want to search for those threads-FWIW

Hillbilly-Hightech · May 2012

how much lump did you have? sounds to me like maybe you didn't have enough lump, and perhaps the fire didn't have enough fuel.

Also, this: "My Daisy wheel lost adjustment so I eyeballed it back" - can be avoided if you just make sure the "screw" which holds the top part of the DW to the bottom part of the DW is ALWAYS facing toward the front, relative to how "open" you have the top of the DW. This means that, as you adjust the DW open or closed, you'll have to rotate the bottom left or right to accommodate.

Go here: http://www.nakedwhiz.com/ceramicfaq.htm#dwinfo

and look for the answer to this question: How Does The Daisy Wheel Top Work?

stike · May 2012

Dismantle everything and start over

BRush00 · May 2012

Sounds like between the tinfoil ends on your grate, and your chicken, you blocked off almost all of the surface area of your cooking grate - is this correct?

If it is, you probably seriously choked the fire down by restricting airflow to the top of the egg and thus out. Air that can't go out, can't be replaced with fresh air in the bottom.

Grillopotamus · May 2012

If you lower your temp to 350 and cook direct (start breast side down for 15 - 20 min, then flip to cavity side for 25 to 30 min), your butterflied chicken will come out with crispy skin and moist, flavorful meat.

gdenby · May 2012

Step thru the process. As you said, you had a rock steady temperature for 30 minutes. Whatever the set-up and amount of fire, that was not changing the temperature.

And then you put the bird in. I'd have to say, that was the blockage. Its not hard to slow the airflow with a lot of food on the grill.

Assuming the "petal" section of the daisy wheel is closed, changes in the "petal" openings will only changes the temp by about 10F. If the petal portion is slid off to the side, there can be a large temperature change, but I'd guess that you restored it to close to where it was.

I'd guess that the reason the temperature didn't drop at first was because after 30 minutes of steady temperature, the ceramic had enough heat stored that the blocked air flow did not show as a temperature change. Once the stored heat was gone, you needed to find a different vent setting to get the dome temp you wanted.

Chumly · May 2012

My setup was very similar to the one found in this video at 12 minutes in

http://www.youtube.com/watch?v=bvsXgmpvL4w except that I used a second grate instead of the platesetter, and used a small round pie polate for the drip pan. I also had more vertical room between my drip pan and the top grate theoretically allowing more air flow between the staggered opened and closed portions of grate. I must admit that the whole time i was making the setup i was thinkning"this just isnt going to allow enough airflow" but i did it anyway.... a dumb stubborn move on my part.

Hillbilly Hitech - I had the lump filled about an inch above where the firebox and fire ring meet.

gdenby - You just said verbatim what i was thinking myself.

Im also starting to think that since its a small egg that my cleaning needed to be more thorough than it was, despite the fact that this was only cook number two I think it was more fouled up than I thought

I cant complain with the eggs performance, My homade enginnering and I caused it a lot of problems and the food still came out unscathed. I figure it is a learning experience. Im sure it takes a while to get the hang of it all and become super picky and precise with controling the egg. This was only my second attempt at the helm, so on to the next attempt. (The first one was just firing it up and seeing if i could make it do what i wanted with no food in it)

I appreciate everyones feedback and look forward to trying this again both direct and indirect versions.

Thanks again!

Chumly · May 2012

lousubcab - I have been searching the board due to some grumblings I have recentlyheard regarding issues with the Small BGEs. Definatley found some good tips, tricks and products.

Internal airflow/convection disruption and Temperature Control

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