Origen: 36" Pompeii Oven Build: Just getting started and have some questions....

[SableSprings]

What you describe is the chamber choked with fuel. In kiln firing this is called a reducing atmosphere and can often lead to a temperature drop. I've done the same with my oven, the wood just goes black and won't burn. It's easier to do in a small oven where the volume of too much wood also reduces the volume of the combustion chamber. If you have flames going up the chimney then this is an indication that you've loaded too much fuel into the chamber. You want to get the chamber full of flames and just have them slightly licking around the top of the oven mouth. For an ideal oxidation atmosphere less is best and you get a faster temperature rise. Otherwise it's just like a car running on an over rich mixture, a waste of fuel and less than ideal combustion.

Thanks David--I appreciate the appropriate phrase for the oven situation I had! My neighbor retired as a city fireman and from his point of view I was describing and experiencing a back-draft in the oven. I'm sure for kilns and WFOs, it's more properly termed a reducing atmosphere situation as you noted. Physically/chemically, I suspect they are probably pretty similar situations...probably, just the difference in scale as much as anything. Thanks again for the more relevant phrase.

[Origen]

So...for how long do you burn a fire where the chamber is filled with flames, and the flames are lightly licking the entry arch? I don't really have a reference point as to how long a fire needs to burn to clear the dome. I have had two fires that meet your description, and only a very small amount of creosote has burned off the top dome. By small amount, I mean maybe two square inches. I kept those fires burning for at least an hour or hour and a half at that intensity. I have been burning a motherlode of wood curing this oven! I didn't quite expect that! Should I just start a big fire and keep it going until clearing? Can you venture a guess as to how long that would be? The dome and floor after those fires was at least 700 degrees. After that temp moderated a bit I made some sourdough baguettes that were deadly.

As a related aside: Last weekend I went into a local restaurant that has a 60" WFO. Now this oven has been in service for a number of years so it is certainly fully cured. There was a small fire off to one side in the oven: maybe 3 or 4 3" logs glowing red, sitting on a 4" bed of red hot coals, not a lot of flame, but some. While talking to the owner, I asked what temperature was in the oven, and he said probably 1000 degrees! That's what I'm after!

[Toomulla]

I never have a fire theat fierce, I take about 2 to 2.5 hours to reach temp to clear the dome completely,once I have a good amount of coals and fire I move it to the back and side which helps clear the dome. I would question the 1000 degrees the only time I had mine that hot the pizzas were black. I suggest you reduce your fire and extend your time. Which is also kinder on the structure

[RandyJ]

I am not so worried about the size of the fire once it is fully cured. But I would say it takes about 2.5 to 3 hrs for my dome to clear. As for three pizza burning it you have the proper floor material with a low enough thermal conductivity you can cook at 1000F floor temp. Most of us on here are best off at around 650-700F with cook times around 2 to 3 min. 1000F would be cook times around 45 sec to 1 minute. But anyway I would say he was probably 7-800F because you need a pretty good fire to keep a temp that high.

Randy

[deejayoh]

I agree with Randy - you need fire to keep the temp of an oven over ~750. I cook with a flame licking up the dome, I like the oven to be around 900 for making pies.

Check out the chapter on fire management in "The Art of Wood Fired Cooking". I have linked it a couple places already on the forum, it's available on Google Reader.

[RandyJ]

Hey DJ are you saying the dome around 900F or the floor? I would agree that the dome at 900F is good and that gives you a floor temp around 750 to maybe 800Fany hotter and I have issues with burning the bottom before I have a pizza that is stiff enough to pick up and dome to. Finish cooking. I am tempted be some of the ultra low thermally conductive tiles if I do a next oven.

Randy

[deejayoh]

I keep it as hot as I can - maybe not 900, but I find the way to get a 90 second pizza is to have floor temps in the 825-850 range. I do not find I have issues with burning the bottom. You may if you are using cornmeal to slide the crust (yuck) or adding oil to the crust. When I was in naples, I noted that they use semolina to slide the crust. I was a little surprised by that. I just use AP flour.

This doc is supposed to be the official guidelines for "Verace Pizza Napoletana". I think their C to F conversion a little off...
http://www.pizzanapoletana.org/publi...02008%20UK.pdf

The following temperature guidelines should be met:
Cooking surface temperature: 430° C about (905ºF). ---> me thinks 800
Oven dome temperature: 485° C about (800ºF). --->me thinks 905
Cooking time: 60-90 seconds.

[RandyJ]

I do use corn meal. I have been thinking of trying semolina I have heard that is better. I also have recently moved away from adding oil and sugar or honey. So I need to give this a shot and see if I can get to a under 2min pizza. I know a full 900F + will give 60 sec pizzas. My last cook was floor around 700F and dome 825ish. And a little over 2 min per pie.

Randy

[SableSprings]

DeeJayoh, Randy -- Have you tried rice flour instead of corn meal or semolina for the peel? I put my rice flour (bulk prices run at just over $1/pound here in Oregon) in a shaker and it doesn't take much of a dusting to do the job. All options work in perfect conditions, but the wetter your dough (or the sloppier your toppings have been applied ) and the more time it spends on the peel, the more likely the pizza skin will stick with wheat flours. That's why corn meal, semolina, & rice flour work better...the meal & semolina are larger grained and less absorbent while the rice flour is fine grained and (IMHO) not absorbent. I use the rice flour for all my bread work as well...dusting baker's couche cloth, bannetons, and basket liner cloth. Even using very wet doughs, I count on the rice flour to release the dough cleanly from the proofing form...and so far (and over 3,000 loaves and over 6 years) no problems.

Origen, I suspect the restaurant owner you talked to just pulled 1,000F cooking floor temp off the top of his head rather than from experience or actual data. I always go talk to the person cooking the pizzas in restaurants and ask about temps. Most of the commercial ovens have a digital temp readout somewhere on the front panels or base...and the vast majority of them sadly show a floor temp of 500F or slightly higher . As you have already seen, it takes a fair amount of wood and time (like everyone else has noted--a couple of hours is realistic to bring the entire oven mass up to carbon burning/pizza cooking temps)...and you seldom see that much wood in the restaurant to maintain high temps for the hours they're open.

(I've also wondered about all the air conditioned air being cycled through the oven as it breathes ...I count on drops of 100F degrees in a couple hours with a partially open fire door after I've pulled or reduced the fire for baking bread or meats.) Note that it's hard to tell if the fire off to the side is really what's heating the cooking floor. A couple wood logs or a gas jet burner bar off to the side can often be more of a show...the real heat source is very probably below the cooking floor in the form of gas/electric burners.

[deejayoh]

Hey Sable - good point about rice flour. I use it in my bannetons as well - but I haven't tried it for pizza. I know it is also supposed to be good because it doesn't burn like wheat flour, so you don't get black ash on your cooking surface.

[Origen]

Apologies for my delayed response: Thank you all very much for your input. This is a clear example of "you'll know it when you see it"! I didn't fully understand "clearing the dome" until I cleared the dome. It was very helpful (reading your comments) to understand what others have done; but it is really only understood through the experience. After a number of subsequent fires and cooking experiences, I do not believe that restaurant owner's oven was a 1000 degrees. I've experienced a 1000 degree oven and that wasn't a 1000 degree oven! He didn't pull that number off the top of his head but about three feet lower.

I actually purchased the book referenced above. It was really helpful from the standpoint of process: that is, oven management and cooking technique. I'm sure all that info is available here, but for me, a book is good.

Another interesting thing (you all know this, but it is just an observation I wanted to lay out): The more the oven has been fired, the smoother the clearing, the more even the heating, and a much longer retention of heat once the fire is out.

The rice flour is an excellent suggestion--works really well! Thank you for that! I was using cornmeal (which works great), but it is a little dirty! I've also used the rice flour in bread making, and it has been a godsend (think biga ciabatta); makes dealing with sticky dough tolerable. I cant believe I've spent all this time on the planet and didn't know about rice flour!

One more thing: I made a broom to sweep out a cool oven: a horsehair drywall stippling brush on a short painter's extension pole. It works really well for getting the floor/wall juncture of a round oven. Horsehair also does a great job of thoroughly removing fine ash due to it's length and softness. I'm sure someone has already thought of this, but I wanted to toss it out. I'm going to try to post a photo, but I sometimes have problems with that.

Thanks all!

[Origen]

Here it is!

[n8huntsman]

Is this what I should be looking for: https://www.amazon.com/Thai-Rice-Flo...5%3A2470955011

Would a regualr grocery store also have it maybe cheaper or smaller package? Not that $5 will break me but not sure I need a whole pound if Im only putting it in a shaker. Confusing looking at all the rice flour options, gluten, gluten free, brown, thai....

[JRPizza]

That package looks like the rice flour we bought - just opened a new package tonight. Like the folks above, I use it to dust my bannetons (bread forms) and it really does the trick keeping the loaves from sticking.

[SableSprings]

Is this what I should be looking for: https://www.amazon.com/Thai-Rice-Flo...5%3A2470955011

Would a regualr grocery store also have it maybe cheaper or smaller package? Not that $5 will break me but not sure I need a whole pound if Im only putting it in a shaker. Confusing looking at all the rice flour options, gluten, gluten free, brown, thai....

Most stores that carry bulk food items will have rice flour. I suspect you've got a Whole Foods in the area and am pretty sure they will have it...not the cheapest but a lot less than $5 per pound. I buy mine for $1.89/lb and store it in a snap top container with a wide enough top that I can dip in my shaker can to fill. My local store is like your Ralph's and since rice flour is used for gluten free baking it's appearing in overpriced packs, so beware and check around your local stores for the best price...normally the bulk bins.

p.s. Just plain old white rice flour is all you need...and just like flour, wear an apron because it gets everywhere when you're dusting with it