Dome size and thickness

[jonv]

Hi folks,

It?s been great to look through so many builds, glean so much useful information, and see the remarkable craftsmanship on display in this forum... but now that I am planning my own WFO build I finally have to stop lurking and ask a couple of newbie questions

I definitely want to build a round domed oven like most of those I?ve seen here, rather than a barrel, and it must achieve those high temps for great pizza, but I also want to be able to bake plenty of bread. Although I have figured out most of the details of the construction I am still not sure on two points of scale: namely the ideal internal diameter of the dome and the thickness of the dome.

I am tempted to make mine at 1200mm / approx. 47? internal, but I see that most builds are in the 32 to 42? range, and I guess there is good reason for this. Is 47? a bit mad? Do those of you with 42? ovens ever wish they were a little bigger, or are they plenty? Even drawing it out I couldn?t be sure ? I?d hate to make it at 42? and wish it was a little bigger afterwards. For pizza, I?m sure a smaller oven would be fine, perhaps better (?), but I am wondering about the bread side of things?

As for the dome, what thickness / thermal mass would folks recommend, particularly with bread in mind? I will certainly be insulating it thoroughly, but any views on the thickness of the brick dome and any further render before the insulation layer would be very helpful.

Finally, can anyone recommend a suitable bench saw (that is available in the UK) for the brickwork, that will not break the bank but still do a decent job on all those angled cuts?

Thanks in advance

JV

[david s]

Re: Dome size and thickness

How much bread are you intending to bake?
Are you intending to bake bread on a commercial scale?

[jonv]

Re: Dome size and thickness

I guess one of the problems is that I'm not quite sure... I am certainly a bread enthusiast - I've even written a bread book, which I hope to publish in the next couple of months

I have a lot of people that are after my bread, so I could end up wanting to bake quite a few loaves, but I suppose probably not what could be called a commercial scale... but quite likely rather more than the average home bread production, at least from time to time.

What I haven't really grasped yet is, once the oven has cooled to bread baking temps, how long it might hold a useful temperature, say from 250 to 200C (480 to 390F), so that I could figure out how many batches and of what sort of bread I might be able to load. I have never cooked with a WFO so I have no feel for the limitations.

[benny8]

Re: Dome size and thickness

I built my oven 3 summers ago. It has 2.5" dome thickness and a 30" diameter. I built it out of Homebrew Castable Refractory. It cooks pizzas at 700+ degrees. When I am done, I rake out the coals and let the temp drop to about 400 degrees and bake bread. My oven will hold 8 loaves. We baked 24 loaves one day and could of baked more if we had some ready. This size works well for our home and we have even had Pizza Cookoffs. Last year we cooked 64 pizzas in 4 hours and this years cookoff we cooked 36 pies. We are in the design phase of a 40" oven on a trailer for Farmers Markets, Fairs and Weddings.

[jonv]

Re: Dome size and thickness

Hmm, I tried to reply last night, but the msg has disappeared - don't know what I did wrong

David - good question, but one I am struggling to answer. I am definitely a bread enthusiast and have plenty of people chasing me for bread - I have even written a bread book that should appear in a couple of months? time I would (probably) not expect to be baking on a commercial scale, but could be looking to bake, on occasion, a fairly large batch. I realise this lack of clarity on my part is going to make the decision a bit difficult!

Whilst I have learnt a lot about the construction of a WFO, I have never used one, so have no feel for how it might perform. When it has cooled to useful bread baking temps, which, for me, are 250 - 200C (480 - 390F) in a conventional oven, how long does a WFO of a given scale maintain those temperatures? How many batches of bread might one reasonably expect to load? I really haven?t a clue on these points?

Benny8 - thanks very much. This sort of information helps give me some idea If you were to start at a bit higher temp, with suitable bread forms for it, how many batches do you think your oven could manage before dropping much below, say, 370F?

[benny8]

Re: Dome size and thickness

I would guess I could easily bake 2-3 loads at those temps, possibly more.My oven will stay warm for a day or more with the oven door in place. The temp will gradually drop, but very slowly.

[GianniFocaccia]

Re: Dome size and thickness

Hi Jon, and welcome to the forum.

I have a 39" pompeii oven made of 4.5" thick firebrick. It is insulated with 5.5" of underfloor insulation and 8'-10" of insulation around the dome. Pizzas come out fantastic but a couple of inches of dome thickness would extend my bread baking sessions.

I don't think a 47" oven would take that much more wood to fire than a 42" oven, and remember, an oven with a round footprint limits the amount of bread you can put in it.

My thoughts - Use a dome template instead of an indispensable tool to create a low dome oven, which is better for bread-baking and superior for pizza. Make a slightly wider door (21-22" for a 42" pompeii) as it will assist in loading/unloading loaves via a peel. Put in more insulation than you think you need.

Good luck,

John

[jonv]

Re: Dome size and thickness

Good info - thanks

What insulation did you use under the floor to make up the 5.5"?

How long would you estimate your oven holds a good bread temperature for?

I will revisit the dome shape - I had planned a hemispherical dome, but will look again at the arguments in favour of a lower dome - thanks

JV

[GianniFocaccia]

Re: Dome size and thickness

I placed 2" of ceramic fiber board on top of 3.5" of wet vermicrete. The bottom of my concrete support slab is imperceptibly warm the morning following a pizza session, even though I have 3cm of soapstone sitting on top of 2.5" of firebrick.

My oven, with the door on will register 150F or so on the fourth day. With a full oven bake, I can only get one batch of bread baked at 450F. The temp is typically around 400F after the first batch.

My thoughts on low-dome profiles for bread were formed from looking at many brick bread oven designs. I know the soapstone floor contributes to bread-bottom burning, but I feel that if my hemispherical oven was lower, the bread tops would brown more quickly, allowing me to shorten bake times and contact with the floor.

[jonv]

Re: Dome size and thickness

Thanks for the info - lots to think about

[Audionatic]

Re: Dome size and thickness

GF-
Would you detail the layers and order of the 8"-10" of dome insulation you put on? I'm in the process of insulating my 40" barrel-vault this weekend. I used 4.5" thickness firebrick both for the dome and hearth. Dome is clad with an add'l 1.5"-2" of home-brew on the sides and approx. 3-4" on top. 4" CF board under hearth. Any advice regarding the insulation would be appreciated. I'd like to over-do as much as is practical. Thanks.

[GianniFocaccia]

Re: Dome size and thickness

Audi,

I went with a lower-end ceramic fiber blanket for my hot face (directly against dome) insulation. The owner of a high-end refractory insulation distributor told me it works just as efficiently as the fine expensive stuff, albeit it's 'gritty' and just not as pleasant to work with.

Also, the 1"-thick rolls are much easier to cut and form to your dome than the 2", I feel.

http://www.fornobravo.com/forum/8/oc...o-7122-24.html


After four layers of 1" CF blanket, I filled the void with regular rockwool insulation that I got from Lowe's. In some places (corners) its probably 14-16"-thick, but hey, one can't over-insulate, right?

HTH,

John

[Simon-T]

Re: Dome size and thickness

Hi folks,

It?s been great to look through so many builds, glean so much useful information, and see the remarkable craftsmanship on display in this forum... but now that I am planning my own WFO build I finally have to stop lurking and ask a couple of newbie questions

I definitely want to build a round domed oven like most of those I?ve seen here, rather than a barrel, and it must achieve those high temps for great pizza, but I also want to be able to bake plenty of bread. Although I have figured out most of the details of the construction I am still not sure on two points of scale: namely the ideal internal diameter of the dome and the thickness of the dome.

I am tempted to make mine at 1200mm / approx. 47? internal, but I see that most builds are in the 32 to 42? range, and I guess there is good reason for this. Is 47? a bit mad? Do those of you with 42? ovens ever wish they were a little bigger, or are they plenty? Even drawing it out I couldn?t be sure ? I?d hate to make it at 42? and wish it was a little bigger afterwards. For pizza, I?m sure a smaller oven would be fine, perhaps better (?), but I am wondering about the bread side of things?

As for the dome, what thickness / thermal mass would folks recommend, particularly with bread in mind? I will certainly be insulating it thoroughly, but any views on the thickness of the brick dome and any further render before the insulation layer would be very helpful.

Finally, can anyone recommend a suitable bench saw (that is available in the UK) for the brickwork, that will not break the bank but still do a decent job on all those angled cuts?

Thanks in advance

JV

Hi, I am a craft baker by trade, although not my main job now. I also live in the UK & looking to build my first pizza oven, would also like to use for baking traditional bread as well as pizza :-)

I was thinking of building a 42" dome, not sure on height though. Also interested in any cutter recommendations in the UK.

Frustrating that I am unable to join the main American 'Forno Bravo' site to download the PDF plans, seems registration is limited to America.

If anyone has a digital copy, I would appreciate a copy - (hope its not against any rules).

Looking to start my build as soon as the weather improves, will be a slow process I am sure!!

Would be nice to hear from others in the UK as to where is the best place to get materials and tools etc....

thanks you.....

[oblertone]

Simon, without wishing to detract from this forum a more UK centric resource should be found by googling the terms 'U.K.' and 'wood fired oven'. While it very much the baby brother of this place you will find UK suppliers (including discount), WFO builders of all types and much relevant experience.