Cooking Pizza in a Masonry Heater?

[ryanbinkley]

Has anyone here ever cooked pizza in a bakeoven that is installed inside a masonry heater?  I have one of these, and have no problem getting it up to to temp during and after a burn (700-850 usually) but the problem is that when I cook pizza in it, the entire oven is that temperature.  This means that the bottom and sides cook really quick (2-3 minutes) but the top barely gets cooked.  The cheese has no spots, and the top of the crust is white. 

I've tried to cool the deck temp some by adding a pizza stone that is about .5" above the deck, this helps some but only resulted in about a 50 degree difference between the dome temp and the deck temp.

If anyone has any ideas for increasing the dome temperature, relative to the cooking deck temperature in a masonry heater I would be all ears. 

[buceriasdon]

Could you post a link to a picture of your setup? It's difficult to know what it looks like. How much space in your inner oven is there? Sounds as if you neeed to raise the pizza closer to the roof but I'm just guessing.
Don

[ryanbinkley]

Here are two pics of the inside of the oven, and a quick sketch that shows how it works.  It isn't a traditional dome really, the top is fluted to promote secondary combustion during the burn, to make it more efficient and extract more btu's out of wood.  I suspect this isn't the ideal oven shape however. 

Looking at these pictures, it seems like the proportions of this oven are off, compared to a traditional pizza oven, it seems too tall instead of wide and relatively flat like a real pizza oven.

After reading around this forum some, I'm thinking that the top is just too far away from the pizza, so I could either raise the deck some, OR add a top stone?  It seems like that has worked well for others, and if I got something slightly more conductive than fire brick (which the deck is made out of) like soapstone, it might help.  I could probably set a slab up on a row of fire bricks, so it would be 2-3" above the top of the pizza.....it would be hot though, like 700-800 degrees, so maybe it would want to be higher?  Thoughts?

[scott123]

Ryan, is the fire box directly beneath the hearth or below and to the side? Is the fire burning as you're baking the pizza? How tall are the flames?

I don't think conductivity helps you in the ceiling the equation.  Conductive materials are not necessarily better radiators. In fact, if the material is conductive enough for the temperature of the ceiling to drop substantially during the bake, radiation will be impaired. Ideally, you want something dark, thick and not that conductive.  I'm still looking for the ideal ceiling material, but, for now, dark red quarry tiles supported on angle iron seems to be a pretty good contender (and pretty reasonably priced).  Whatever material you use for the ceiling, the most important aspect will be proximity.  If it turns out that your hearth and ceiling end up being pretty close to the same temp, then you'll want the vertical gap as small as you can comfortably work in- if you can launch a pie with a 3" or less vertical gap, that's ideal.

[ryanbinkley]

Interesting, I didn't understand the difference between conduction and radiation really. 

To answer your questions, the fire box is directly below the deck.  I usually try pizza toward the end of the burn when the flames are just barely up to the level of the deck.  During the active burn stage, there is secondary combustion happening in the oven chamber and it is hot/violent/smokey so I can't really bake then.  I don't know how hot it gets, because my thermometer maxes out at 932, but secondary combustion usually occurs around 1200 degrees so its near there. 

About 20 minutes after secondary combustion, the whole oven lingers between 700-850 for a while, thats when I usually slide pizzas in.  I can hold it at that spot for a while by adding more wood in the fire box below if necessary.

I have experimented with building a fire in the oven itself, like a regular pizza oven, but the lack of the dome and the high ceiling seemed to keep the top from cooking enough. 

To keep the top stone hot, I could easily build a secondary fire on top of it, just something small to keep coals going, it would keep the stone piping hot for a long time.  I just need something that will radiate that heat downward.....I saw somewhere that you mentioned using a steel top stone in a low temp oven....what about a cast iron griddle as a top stone? 

I guess what I need is something that will absorb a lot of heat, and then quickly radiate it downward to the top of the pizza....ideally faster than the fire bricks in the deck are radiating heat upward into the crust.  What about a steel plate with fire bricks on top of it?

[ryanbinkley]

Also, what are dark red quarry tiles and where would I find them?  Are they stone or ceramic? 

I was hoping that someone else had a masonry heater and had been through this, but it's kind of a rare setup I guess.