The Thermal Layer, Firing Your Oven

This was a serious source of frustration for me. Everything I read and watched said something different. Some sites said fire your oven right away while others said to wait for weeks and then build small fires slowly building in intensity over many different time frames. Still other information said not to fire the oven’s thermal layer separately but, to build the entire oven and let it dry for weeks and then fire it. Still others said just build the dome of the thermal layer and just start using it. Well not all of these sites had longevity in mind and some of them were based on the basic principles of fire makes things hot and were not really designed to be very efficient.

So I made a couple of phone calls to get some information from The University of Arizona. I told them what I was doing and what I had read and asked for their opinion. They were interested in what I was doing and asked me how I was building the oven as well as what I had based my oven design on. I explained that I had settled on the ancient ovens of Pompeii to use as a model for my oven. I also explained that I had added a chimney and discussed the math that I had used to arrive at my conclusions. They responded very positively about my project and offered some suggestions about firing the oven.

Their suggestion that I settled on was to allow the thermal layer to cure for a week then begin building progressively increasing fires once a day for several days. The firing took about a week. The first fire was a small paper and tinder fire. The next fire was slightly larger with paper, a little cardboard, tinder and some kindling. The next fire was again larger made with with paper, cardboard, tinder, kindling, and small branches. The last curing fire was again larger made with with paper, cardboard, tinder, kindling, small branches and some small logs. The duration of each fire also grew longer as the fire intensity grew hotter.

Now as it was explained to me the final firing had to be at an extreme heat for a several hour duration. This would help cure the thermal layer, force any expansion required and begin to change the inside layer of the oven to terra cotta. So I built a good  hot fire for the last curing fire. I started building the fire at about 11:00 AM and continued to build it up until about 9:00 PM.

As you can see I had a seriously hot fire going. You can see how well the chimney works to draw up it. Some nice flames and heat here. We were sitting about 12 feet away from the fire and it was hot.
I took this picture at about 2:00 AM. You can see just how hot the coals are and heat was radiating off of the dome. It was pretty amazing at this point to see what a bunch of dirt and sand can do. The next morning was a Friday, there were still coals burning and the dome was still hot the the touch.
Since it was Friday I decided that I would wait to make dinner until my wife got home. I built a fire in the oven and had my wife stop at the store and pick up fixings for pizza. She came home with fixings for 3 18 inch pizzas with the works and hot wings. So that Friday night was the first meal I cooked in the oven. I moved the coals to the back of the oven and swabbed the bricks with a wet rag to clean off the ash. I put the hot wings in a shallow pan and slid them into the left side side of the oven. Then I used the the right side and the center to cook the pizza. I only put two in then when I pulled them out I put in the third. I wasn’t sure how much room I would need. Next time I’ll just put all three in together there was plenty of room. All I can say is that pizza really has to be the first thing to cook in your oven. Wow there is just nothing like pizza from a wood fire oven. Hungry yet?