My Pompeii Design

[snyderadam]

Hello,

I am considering building a wood fired oven this summer. I primarily want to make pizza in it but would also like to be able to make pot roasts and artisan breads. This past month I reviewed Forno Bravo's pompeii oven plans and searched numerous forums about pizza ovens. I like the concept of the spherical dome to efficiently diffuse heat and maintain even heat. While brainstorming different ideas, my dad and I came up with an idea of having an external firebox. I soon learned that this design is called a "white oven", in contrast with the standard "black oven". From my research I have realized that there is not too much information on "white oven" designs. Also, not many people have designed and constructed this type of design. My original thoughts of the benefits of a "white oven" were to:

1.) Eliminate fire ash and reduce smoke in the cooking dome
2.) Add a design challenge to the project
3.) Potentially maximize the heat management of the oven

I am in the process of making preliminary CAD sketches and assemblies to both propose design specifications and communicate my ideas. I will post these as soon as they are sufficient to be understood by other forum members. I am open to any suggestions/comments about my project and look forward to your input.

Adam

[jeeppiper]

Re: My Pompeii Design

No experience with white ovens, but my guess is that it might be more difficult to get the higher temperatures, since you will be taking heat losses going from the box to the oven chamber. Also will depend on oven size. With a raging fire in my "Black oven" I can get it up to 1200 degrees plus! Cook a pizza in about 10 seconds and burn it in 11! Most folks don't seem to be bothered by the ash management. Just get yourself a long-handled wire brush. I also use a piece of 1" pipe to blow the ash off the cooking area. What part of PA are you located?

[snyderadam]

Re: My Pompeii Design

I live in Northumberland County PA. I am in the process of getting a quote for a firebox I had in mind to see if the cost would be reasonable. I will try to post my sketches by the end of the week so readers have a better idea of one of my concepts. Jeeppiper, I was wondering if you purchased firebricks and if so where. Currently, I found two brands of firebricks I can purchase in PA. The most common-Whitacre Greer (low duty firebrick as per Forno Bravo's plans). I also found an Empire-S firebrick from an ANH Refractories distribution center in Trevose, PA (close to where you live). The Empire-S is classified as a high duty firebrick by ANH, but meets the specifications as a medium duty firebrick (as per Forno Bravo's plans). Do you have any comments on these firebricks?

[Tscarborough]

Re: My Pompeii Design

A true white oven is heated from the exterior, that is, the heat flows around the exterior surface of the oven to heat it. This complicates the design quite a bit. The flue gases have to be directed around the mass of the oven while maintaining sufficient draw to maintain the fire. In addition to warming the oven, you will be warming the fire area and all the mass of the masonry used to contain the flue gases. You will also lose the benefit having the oven mass insulated. There is a reason no one builds wood fired white ovens.

[snyderadam]

Re: My Pompeii Design

Here is my preliminary design of a "white" pizza oven:
(hopefully they post right, I never posted images like this before)

[Tscarborough]

Re: My Pompeii Design

That is not a white oven, it is an externally fired black oven. It is even less efficient than a white oven.

[stonecutter]

Re: My Pompeii Design

My original thoughts of the benefits of a "white oven" were to:

1.) Eliminate fire ash and reduce smoke in the cooking dome
2.) Add a design challenge to the project
3.) Potentially maximize the heat management of the oven

1) If you are running the oven at 700+ with dry hardwood, you will have very little ash and no smoke in the dome.

2) If you have not built a black oven before, even if you are experienced at masonry, then you will have plenty of challenges...especially if you are going for tight fitted work.

3) An occasional use black oven is more efficient than an occasional use white oven....much,much more in fact.

[jeeppiper]

Re: My Pompeii Design

Interesting design. I can envision all kinds of heating troubles with this design. First, you will have a "wind-tunnel" sucking air in and burning wood like crazy. Second, the heating that you will get will be very uneven. Heating the floor will be difficult. Nice thing about the Pompeii design is that the airflow is inherently restricted, so you get a nice, steady slow burn of the wood, giving the firebrick mass to absorb heat.

[snyderadam]

Re: My Pompeii Design

I know this is not a true "white" oven-I am referring to it as such just for simplicity in reference. This is one of my design ideas, different than a standard black oven. I am not set in stone with this design (in fact I might not use this idea at all).

I was also wondering if anyone has had personal experience with these ovens. I can admit I do not know myself how well this will work unless I would build it or know someone who has. There will be a door on the back of the firebox, if that's what you were referring to as a potential wind tunnel problem Jeeppiper. Possibly correct chimney design, door vent control, and even draft inducers could effectively heat the oven. I have the same concern with the heating of the oven floor because I would have just have convection in my design. I am not too concerned with how much wood I burn, but am primarily in concern with the proposed benefits listed in my first post.

I'm not sure if my last post came through. For the dome of oven, I found two brands of firebrick I can purchase in PA. The most common, Whitacre Greer, is a low duty firebrick (not even a low duty firebrick according to Forno Bravo's suggested alumina content). I also found an Empire S firebrick which is classified as a high duty firebrick according to ANH Refractories, but meets the suggested medium duty firebrick according to Forno Bravo's suggested alumina content. I can purchase this brick at the distributor center in Trevose, PA (near where you live jeeppiper). Does anyone have any comments on these types of firebricks or even a castable refractory (e.g. heatcast-40).

Thank you,
Adam

[Tscarborough]

Re: My Pompeii Design

Low duty are fine and indeed are better for the floor of the oven, Whitacre-Greer in particular.

What you are building is more along the design of a masonry heater than an oven, search for that for more information.

[wotavidone]

Re: My Pompeii Design

Hello,

I am considering building a wood fired oven this summer. I primarily want to make pizza in it but would also like to be able to make pot roasts and artisan breads. This past month I reviewed Forno Bravo's pompeii oven plans and searched numerous forums about pizza ovens. I like the concept of the spherical dome to efficiently diffuse heat and maintain even heat. While brainstorming different ideas, my dad and I came up with an idea of having an external firebox. I soon learned that this design is called a "white oven", in contrast with the standard "black oven". From my research I have realized that there is not too much information on "white oven" designs. Also, not many people have designed and constructed this type of design. My original thoughts of the benefits of a "white oven" were to:

1.) Eliminate fire ash and reduce smoke in the cooking dome
2.) Add a design challenge to the project
3.) Potentially maximize the heat management of the oven

I am in the process of making preliminary CAD sketches and assemblies to both propose design specifications and communicate my ideas. I will post these as soon as they are sufficient to be understood by other forum members. I am open to any suggestions/comments about my project and look forward to your input.

Adam

One of the things I'm less than happy about with my oven is that it has too little smoke. I'd like a little more smoke flavour in my food.
I dunno about heat management, but my ordinary "black" oven seems to be very heat effficient. Very little is wasted, and it gets very hot, hence, not enough smoke when cooking my pizzas.
I reckon there are enough challenges in building an ordinary black oven.
I'm about to embark on oven number three - I must be mad.

[snyderadam]

Re: My Pompeii Design

Hey guys,

I am soon going to start some testing on different components of a Pompeii oven. I first will test some refractories I found locally. I will test Whiticre Greer buff firebrick, Empire S firebrick, Clipper-DP firebrick, and KS-4 Plus castable refractory. I can not wait for my testing! I will be sure to post the results I find about different heat properties of these materials.

Adam

[stonecutter]

Re: My Pompeii Design

One of the things I'm less than happy about with my oven is that it has too little smoke. I'd like a little more smoke flavour in my food.
I dunno about heat management, but my ordinary "black" oven seems to be very heat effficient. Very little is wasted, and it gets very hot, hence, not enough smoke when cooking my pizzas.
I reckon there are enough challenges in building an ordinary black oven.
I'm about to embark on oven number three - I must be mad.

This is a new one....somebody that doesn't like how efficient their oven is.

[snyderadam]

Re: My Pompeii Design

Hey stonecutter,

I'm not sure what you were trying to get at in your last post. Wotavidone was just saying his oven WAS efficient. However, I don't think I mentioned too much about maximizing efficiency. If you look at my first post , one of my goals is about heat management. I mean more than just the amount of fuel vs heat absorbed by the oven. I also mean the ability to control heat flow and direction (i.e. heat management). If I missed something you meant please comment.

Thanks,
Adam

[stonecutter]

Re: My Pompeii Design

Hey stonecutter,

I'm not sure what you were trying to get at in your last post. Wotavidone was just saying his oven WAS efficient. However, I don't think I mentioned too much about maximizing efficiency. If you look at my first post , one of my goals is about heat management. I mean more than just the amount of fuel vs heat absorbed by the oven. I also mean the ability to control heat flow and direction (i.e. heat management). If I missed something you meant please comment.

Thanks,
Adam

He said he was less than happy with the oven having too little smoke. A well built, properly dried, correctly fueled oven won't be smoky. It was meant to be tounge in cheek, not literal.