pizza oven heat retention

[taiwanpizzaman]

I use mostly logs that I cut into fairly thin strips. I wouldn't know what wood it is. It is not very soft, so it burns slowly in the beginning, but once firing burns quite nicely. It doesn't burn very long though. If I keep a very big fire going, the pizza oven works very well, we cooked more than thirty pizzas last weekend, but you have to keep piling on the wood to keep it hot enough. I'm looking for a way to make this oven more efficient, perhaps reducing the internal size.

[james]

Hey Colin,

I have moved this thread to Heat Management. Seems like a good fit.

If I were to summarize (in inches):

The floor is 33"d x 25"w
The dome is 17.6"h
The dome insulation is 4.5"
There is 4" sand under the cooking floor
The oven opening is 11" high
The floor is a single firebrick (2.5" or 4.5"?)
The dome is a single red clay (4.5" or 8"?)

Hmmm. I think this oven should cook better than it is. I can't see anything out of whack. Among the things we know:

1. The dome isn't too high.
2. The opening isn't too big.
3. The floor isn't too thick.
4. You can definitely fire and cook with a single layer of brick.

I can only think of four possible things.

1. The baked stone isn't really an insulator, and it is wicking heat.
2. Is there a lot of concrete around the dome that could be wicking heat?
3. There is still a lot of moisture left in the oven (very possible).
4. You aren't building big enough fires (also possible).

If the problem is either 3 or 4, keep burning better fires to see if the oven starts coming up to heat faster and holding heat better.
James

[CanuckJim]

Colin,

Mine is also a barrel vault design, built deliberately with high mass for multiple bakes. My experience is that ovens with this design require firing that is not necessarily hotter, but longer in duration. This gives the mass that you do have time to heat up. If you don't fire longer, the mass will wick heat away from the cooking surface. As an example, if I want to bake bread at 550 F, the mass below the floor should be in the 400 F range. Otherwise, the temp drops off too quickly.

Jim

[taiwanpizzaman]

Thanks guys, I think it might be the fires. I'll experiment with bigger fires and see how it goes. Thanks to all of you out there for your input, it's a great forum and I appreciate all the help. PS: Next time I'm building a round oven!

[taiwanpizzaman]

Thanks James and all you other guys. After reading about firing the pizza ovens and noticing that ALL the walls should be white-hot I was like So this weekend I made an "Agressive" fire. I stacked wood at the back of the oven, the two sides and then the middle-front. The middle fire was lit first and after an hour the two side fires. After two hours the back still hadn't lit up and it looked like oxygen starvation, so I parted the fires and ended up with a blazing inferno

We baked ten pizzas and five loaves of bread (without the door!). When I put the door in the oven stayed hotter than 200 degrees centigrade for more than an hour! If i knew it was going to stay hot for so long I would have planned a couple of roasts as well! Cheers

Colin