I Do Not Understand (Long version)

RhumAndJerk

Or should I say that I re-fired my egg.[p]When I woke up on Sunday morning, I had an inspiration. I was determined to finally try out my kiln shelves. I wanted to try to bake something other than pizza for my first attempt, so I picked Jamaican Meat Patties. I do not know why, I guess that I felt that I wanted to be in the kitchen all day. The recipe was adapted from Traveling Jamaica with Knife, Fork & Spoon by Robb Walsh and Jay McCarthy. Just to give you an idea of what Jamaican Meat Patties are, they are meat filled half-round pastries. Boy did they turn out great and I know what I am having for lunch today.[p]Well, let us start the day.[p]After I put the pot of coffee on, I pulled the meat out to defrost and started the pastry dough. It was fairly basic pastry dough that had tumeric in it. Once that dough was in the refrigerator, I made the kids Buckwheat Pancakes in one of my cast iron skillets. My 4-year-old son is really getting the hang of flipping pancakes. If you have not had Buckwheat Pancakes lately, give them a try you will not be disappointed. Also, my 6-year-old daughter wanted to know where the sausages from the Egg where. We were out and she was disappointed, so was I.[p]When Breakfast was finished and cleaned up, I was ready to tackle the filling. The 1.5 pounds of ground beef had thawed out. To that I added 1 onion, 1 leek, a half of a red bell pepper, 3 cloves of garlic, some fresh grated ginger, 5 green onions and some other stuff that I can not remember. I let that sit for a while. [p]Now we turned to the Cast Iron Dutch oven. I cooked the meat mixture for about ten minutes over medium heat. The meat did not brown just cooked. To this I added 5 cups of homemade breadcrumbs (a loaf of French Bread that sat to long). The recipe called for three quarters of a cup of water, boy was that off. I started off by sacrificing a bottle of Red Stripe and then followed that by about 5 cups of water. This was done to get the correct texture of the filling according to the book. This cooked for about 30 minutes.[p]Pull dough out of fridge and enter Egg.[p]I want to make sure that I built a good fire since I was not sure how two 13-inch kiln shelves would work on my Small BGE (13 inch grill). Well let me tell you I built a fire! I grabbed a brand new bag of BGE Lump and fished out the large pieces and built the fire ala EW Style. The one difference is that after I put down a layer of large pieces I lit the fire and continued to build the lump around it. I really load up the lump. I then placed the grill on and put a layer of kiln spacers, the first shelf, another layer of spacers and the final shelf. I then closed up egg and went in to assemble the meat patties.[p]It takes time to roll out and fill 24 four-inch pastries. I periodically checked the egg to see how the temperature was progressing. The first football game was on the radio. When all was ready, the egg read 450. The recipe called for 30-35 minutes at 400 so I figured that I was about right.[p]Here is what I do not understand; there was a large discrepancy between the dome temperature and the temperature under the kiln shelves. The base was so hot that when I touched the outside of it to lift the lid I burned my fingers. I still have a blister on my little finger (Place hand on cold beer, drive on). Sometimes when you play with fire you are going to get burned. The base was so hot that it burned the wooden handle where it was touching the base. How is it possible for the temperature difference to be this great? I wish that knew how hot the fire really was because it had to be in upper 1000. [p]Here is how the meat patties cooked. I sprinkled some corn meal on the kiln shelf and placed eight of the patties (24 total) directly on the shelf. The dome temp read 400. I cooked them for 30 minutes. The bottoms were burned black and the tops were done. Of course I ate them. The next batch I cooked for 25 minutes flipping on the half. The dome still read 400. These came out perfect. By the time the last batch was put on, the dome temp had fallen to 350. I cooked for the same 25, flipping on the half. They were a little underdone, but done. [p]I finally sat down to watch some football with a Red Stripe and some Jamaican Meat Patties. Yum, Yumm, Yummm. It was all worth the effort.[p]Many many hours later when Mr. Egg cooled off, I removed the kiln shelves. The firebox and fire ring were bleached a beautiful white and my extra load of lump was barley a pile ash. The total burn time was about three hours. I have not yet determined the condition of the grill, I look when I get home. [p]Hey KennyG, if you have to stop downtown, I will save you one. I also have some at home.[p]RhumAndJerk

Nature Boy

RhumAndJerk,
Sounds grand! I love new stuff, and that sounds like a great idea. Self cleaning to cook at those temps! Your egg will be just fine.[p]Thanks for the great story.
NB

Teslamania

RhumAndJerk[p]Boy, with a 13inch kiln shelf in your 13 inch egg, there must not have been much room around the edges of the shelf. My theory is that with no ceramic mass, the Egg is one big chamber and the upper and lower parts of the egg are at about equal temperature. With the shelf, heat shield, or whatever in place, the heat is concentrated into a smaller area (approximately half) and the upper part of the egg is heated by indirect methods (conducted heat through the ceramic mass and by convection - hot air. The ceramic mass blocks radiant heat. To heat the upper part of the egg to the desired temperature, more lump is consumed to get to a given temp (compared to without the ceramic mass). Also, all that radiant heat is radiated over a smaller surface area, so the bottom of the egg gets hotter than normal (more heat radiated over a smaller area) and the higher burning temperatures (more lump consumed). That is why you have a "self cleaning oven" effect. I also suspect that these higher temps lead to cracks in the fire box and in my case, the fire ring. [p]Glad to hear that you enjoyed the dish you made, sounds great.

RhumAndJerk

Teslamania,
Great deduction. Hairline cracks enlarged to bigger cracks. I have to do a full inspection of the base.[p]I am still curious though, there had to be at least a 1000 degree temperature differential between the base and the dome. If the air was circulating enough to stoke the fire that high, then why wouldn’t heat also rise to the dome? I understand about the radiant heat, but by a factor of two or three?[p]There is also something to do with a single shelf vs. both shelves spaced apart. If I had placed both shelves directly together, would the same thing happen?[p]Last thought. If the firebox and fire ring are made out the same material as the base, the why doesn’t the base crack also?[p]RhumAndJerk[p]

Spin

RhumAndJerk,[p]Your bake sounds delicious and the setup seems to be working nicely for you. More lump is consumed in heating the shelves. I load the small up to just shy of the grill when making pizza and can cook at 550F for about 1.5 hours. Though the bottom half will be hotter than the dome, I haven't burned the handle.[p]Spin

Nature Boy

RhumAndJerk,
I guess the airflow goes around, but the ceramic mass sucks up all of your radiant heat, and leaves a big void in the dome. A double shelf would just create that much more mass.[p]Do they have 10 inch shelves?? Maybe experiment with smaller ones.[p]Just some thoughts.
NB

RhumAndJerk

Spin,
The lump was up to where you suggested. I expected the lump to be gone, but I did not expect the high base heat.[p]What size are the stones that you use on your small? [p]RhumAndJerk[p]

Spin

RhumAndJerk,[p]Did you cook with the daisey on? Air can circulate in and out the bottom vent alone and feed the fire. Cook with the top open and regulate temperatures using the bottom vent only. This will allow the heat to move up through your EGG and should make the temps of base and dome more even.[p]Spin

RhumAndJerk

Nature Boy,
A wonderful thought. The distributor only had 13 inch and bigger. However, they did have hexagon shaped ones.[p]I am curious as to how a single shelf works.[p]The good thing to report is that the kiln shelves took the heat with out any signs of cracking. Anything less would have been a pile of sand. Take that Pampered Chef. [p]RhumAndJerk[p]

RhumAndJerk

Spin,
I ran the egg wide open at both ends. Maybe I should have adjusted the bottom vent. Is it possible, that once the fire took off, it took on a life of its own in the base only?[p]RhumAndJerk[p]

Spin

RhumAndJerk,[p]I have two 12.5" round ceramic shelves that I use in the small.[p]Spin

RhumAndJerk

Spin,
Do you use spacers? Or do you just the place the two shelves together?[p]RhumAndJerk

Spin

RhumAndJerk,[p]I use one for indirect cooking of meats and both stacked directly on each other for baking and pizza. I always use a spacer under the stone(s) to allow air to circulate.[p]Spin

RhumAndJerk

Spin,
That must have been my mistake was the second set of spacers between the shelves. [p]I am still amazed at the temperature differential though.[p]Thanks,
RhumAndJerk[p]

Spin

RhumAndJerk,[p]Sure. For smoking bacon (low temp) I use the ceramic top and leave the bottom vent wide open. I have yet to have the fire go out. Smoke will wisp out and then be sucked back in as the fire breathes. It takes quite a bit of time for the mass to heat up and until it is hot, it will keep the dome temp from rising. Maybe a longer, slower heating will help.[p]Spin

Teslamania

RhumAndJerk,[p]Great observations and comments. I think radiant heat is a big factor. Think about when you are cold, in front of a fire. If your wife or kid gets in front between you and the flames, you don't get as warm. Radiant heat is a big factor i think. Yes, hot air rises, but it mostly would go along the sides, and up and out the vents in the egg. As to why the base of the egg doesn't crack, maybe it has to do with geometry, or the thickness of the base. Also, the walls of the base are not exposed directly to the flames. Most of the heat that gets to the sides of the egg would be via radiant heat. Just my humble opinion though.