Fire: Too Hot - Too Cold

[eprante]

We cooked 21 pizzas the other night for a party. I hadn't measured floor temps before so this time I did. The floor was at 725 when we started, the dome had cleared. My internal probe mounted 4" above the floor had been as high as 800 but was about 650 when we started cooking. The floor temp held above 700 most of the night as I checked it, we kept adding wood to keep the oven in 650-750 range while cooking. Pizzas cooked in 2 minutes. I use Caputo 00 for my dough, it works like a champ. As usual no pictures because I was busy cooking, but the favorite pizza was pesto, prosciutto, garlic and mozarella with some fresh thyme sprinkled on top.
Eric

[heliman]

Thanks Eric - i will be have a go making some pizza without semolina one of these days. It seems to have a lower resistance to burning. May have to trade off some crispness for an unburned bottom! Would be great to be able to get Caputo flour here at a reasonable price though...

[texassourdough]

Hi Rossco....

I am not aware of semolina being particularly sensitive to hearth temperature (relative to regular flour) but any burning issues should be easily resolved by simply reducing the hearth temperature a bit. My normal test for hearth temperature is to throw about 1/8 tsp of semolina onto my hearth. If the semolina turns black in less than three seconds the hearth is IMO too warm. If it is much over 3 seconds it is too cold. And three seconds is about right. Though my dough is flour based (for I don't use semolina in any of the doughs I routinely make). IF dough containing semolina is more susceptible to burning perhaps the answer is closer to four seconds. I like the semolina test because it uses materials I have down at my oven when cooking pies doesn't require me to carry my UV temp gun down and back. The reason I use semolina over flour is the larger granularity makes it work better but one can get similar results with flour or corn meal (but corn meal makes a less appealing flavor on the bottom of the pizza IMO so I use semolina on my peel).

Enjoying your trip reports!
Jay

[Mitchamus]

Hi Rossco,

anything above 400 on my hearth and I get a burned base as well.

I am using a straight commercial pizza flour, with the normal hydration.

I have read that 00 flour doesn't burn as easily. can't say (from experience) if this is true or not..

cheers,
mitch.

[louise]

Hi Guys,
i am new to this. My uncle built a pizza oven recently. We have lit fires in it for the last few weeks just to cure it but on saturday we lit it for real. Im not sure why but the pizza's would not cook. The base is 30" diameter and the floor to celing is 23" the opening is 18" wide and 15.5 high. The materials used for the oven 2" sand behind brick and 2" of insullation. After hours of waiting and lots of hardwood no luck. We are totally confused to why the oven would not get to the sufficent heat. Any suggestios pleaseeeee

[shuboyje]

Sadly I see a lot of reasons why you are having issues. A 23" high dome on a 30" oven is way to high. Even a full hemispherical dome would only be 15". The next issue is the opening size. An 18" wide opening in a 30" oven is pretty big, and you are gonna lose a lot of heat. Last issue is the 2" of sand and 2" of insulation. Sand adds to the thermal mass, and if you already have fairly thick bricks the result would be a very massive oven. Also depending on the type of insulation, 2" is not much. If it is a blanket you may be able to slip by with two inches but if it is vermiculite or perlite you would need at least double that, and triple would even be a good idea. So now to sum it all up: A oven with extra mass to heat up, a very high dome, and very large door, and a lack of insulation probably will not get up to pizza temperatures. You also didn't mention if it is insulated under the floor?

[louise]

hi many thanks for your reply i think ill take some photos and post them to you. Im not sure exactually how it is insulated. He is a stone mason and knows a lot of stone but not about mainting the heat. He spent a long time getting it right. I will get him to write down exactually how he did it and how insulated and i will get back to you. I really appricate this help.

[Spunkoid]

Louise,
I agree with Shuboyje in that it is a pretty large opening and quite high but with good fire management, you should still be able to get it hot enough to cook a few pizzas.

Suggest starting your fire small then building it up hot, really hot. Use dry wood, split it lots, keep feeding the fire and keep it pushed well back into the dome and to the side. Build up a good heavy bank of coals. When the dome is cold, it will likely get black with soot. When it gets really hot, the soot will burn off and you will be able to see the bricks well. Spread the banked coals all around the edge of the dome and add a few sticks of wood to the one side. The flames should slowly lick over the roof of the dome on the inside and lazily come down the other side. You should find it more than hot enough to cook a pizza or two.

On the plus side, with the large opening, and the higher roof, it can be corrected if need be by cutting and adding another layer of fire brick to the floor, you have more than enough room to do it, it just won't be easy.

[louise]

God im amazed at the response i am very greatful. I discussed this with him yesterday and he was concerned about lighting a bug fire as he is worried about the brick. I advised him to make the fire larger and hotter. We are hoping this may work. We are both new to pizza ovens especially hand built brick one's. We will be lighting a bigger fire with more heat on saturday fingers crossed we will get it hot enough to cook a pizza. I will take pictures and post them over the weekend. One again many thanks for all your help. No doubt we will talk soon.


Louise

[GianniFocaccia]

Louise,

I believe another builder here had the same concerns with an opening arch that was too high. Depending on how yours was built, you may be able to build a small arch 'insert' that would effectively lower the entry height. As Spunkoid suggested, if 2 1/2" is added to your floor, your dome height would be 20 1/2". Adding 2 1/2" of arch to the entry would bring you to the ideal dome/opening ratio of 63%. Pics would be helpful.