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Author Topic: WFO Interior Height  (Read 9534 times)

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Bill/SFNM

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WFO Interior Height
« on: May 24, 2011, 03:10:55 PM »
What is the internal diameter? 32 or 33"? If so, 9.5" height would be right in line with Marco's 3.4/1 ratio.

CL

Craig,

I think marco's "golden" ratio is bogus, especially as it applies to smaller residential ovens. I even doubt it applies to full-size ones like yours. Last month I started testing this theory by raising the deck of my WFO. I don't want to hijack Robyn's thread on her oven so I'll post my full results in a few weeks in the "pimpin" thread

http://www.pizzamaking.com/forum/index.php/topic,13620.0.html

shuboyje

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WFO Interior Height
« Reply #1 on: May 24, 2011, 11:12:25 PM »
Wether or not you believe in the results, I do feel the number is an accurate estimate of the dome height of the ovens Marco talks about.  A 3 centered arch is a shape very similar to what Marco describes, and it is a shape in which the diameter determines the height.  No matter what size the arch the height is always very close to h=d/3.4.  I personally feel the ovens Marco describes use the form of a three centered arch modified to have a soldier course.  It only makes since considering it comes from classical masonry.
-Jeff

wheelman

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WFO Interior Height
« Reply #2 on: May 25, 2011, 09:44:34 AM »
neopolitan oven dimensions i've seen before are Height=dia/3 and door height=dome height x 2/3. they do seem to normally have a soldier course and a relatively flat domed roof.  i would think this might not apply exactly to ovens smaller than about 110cm dia.  In this case, i feel sure that those guys have done their homework and built an oven that will perform as well as it looks - which is stunning in my book.
bill

Bill/SFNM

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Re: WFO Interior Height
« Reply #3 on: May 25, 2011, 10:09:21 AM »
I've split this into a new topic.

Don't have time right now to go into detail, but my experience has been that the inverse square law as it applies to heat delivered to the pie from the fire and dome trumps everything. The distance from the fire to the pizza is far more important than the distance from the dome to the pizza, especially for smaller ovens where the pizza must be relatively close to the fire. Secondarily, whatever heat is radiated from the dome is only a function of the distance to the dome and has nothing to do with the diameter of the oven. Marco's ratio dictates that a large diameter oven will have a higher dome may make structural sense, but does not make thermodynamic sense.

« Last Edit: May 25, 2011, 10:13:32 AM by Bill/SFNM »

dellavecchia

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Re: WFO Interior Height
« Reply #4 on: May 25, 2011, 10:17:55 AM »
I've split this into a new topic.

Don't have time right now to go into detail, but my experience has been that the inverse square law as it applies to heat delivered to the pie from the fire and dome trumps everything. The distance from the fire to the pizza is far more important than the distance from the dome to the pizza, especially for smaller ovens where the pizza must be relatively close to the fire. Secondarily, whatever heat is radiated from the dome is only a function of the distance to the dome and has nothing to do with the diameter of the oven. Marco's ratio dictates that a large diameter oven will have a higher dome may make structural sense, but does not make thermodynamic sense.

Agreed, as it applies to smaller ovens. My oven is 28in in diameter, and has a height of 14in, nearly double what the golden ratio would dictate. I have no issue whatsoever with top heat.

John

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Bill/SFNM

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Re: WFO Interior Height
« Reply #5 on: May 25, 2011, 10:41:11 AM »
John, this is what I have been finding when raising the floor of my small oven - the heat from the fire/coals, assuming you are running an active fire, has vastly more impact than anything coming down from the dome.

PizzaPolice

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Re: WFO Interior Height
« Reply #6 on: May 25, 2011, 12:37:56 PM »
How odd!  I was talking to the EarthStone folks about this very thing last week at the Chicago NRA.  The big oven they had on display (6000#) had a very high ceiling.  The guy countered with the fact that is is designed to cook all manner of food but the smaller ovens are lower and more conducent to pizza.  They seemed to know you Bill.

JConk007

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Re: WFO Interior Height
« Reply #7 on: May 25, 2011, 12:55:44 PM »
Does anyone know the ratio of the Stephano ovens ? they seem a bit high but man they cook like a dream!
JOhn
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Jackie Tran

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Re: WFO Interior Height
« Reply #8 on: May 25, 2011, 12:56:38 PM »
So the question is whether an active flame arching over a low dome versus a higher one make a difference?  Assuming you have a heat saturated oven in both instances.

PizzaPolice

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Re: WFO Interior Height
« Reply #9 on: May 25, 2011, 01:41:50 PM »
Another stop made @ the Chicago NRA was The ERS EuroRestaurantSolutions booth.  They featured a Marra Forni oven.  The oven was manned by renowned pizzaiolo Antonio Esposito.  The oven was a true brick Italian made wood burner.  Since it was in McCormick Place, they used natural gas.  The high speed flames shot through a hole in the floor like the devil himself popped to shake your hand.  The flames cause the brick to glow cherry red.  The didn't lick over the dome.  They just drilled that one spot.  As far as the "one Mississippi- two Mississippi" goes, I stuck my hand in and got to "one".  That was truly the hottest oven I have ever encountered.  The hairs on my fingers evaporated.  However, Chef Esposito stuck in a cheese pizza.  About 70 - 80 seconds.  Perfection.  Light leoparding and medium upskirt char.

So is it Low Dome Syndrome or the High Heat Drama?  Not sure.
Jeff Calwell, who was running the booth for ERS, affirmed what we all have been hearing.  It's the factor of four.  The Oven, The Heat, The Ingredients and The Pizzaiolo.

Btw, Chef Esposito has jumped ship from Caputo 00 to Pivetti 00.  The doughs were soft as a newborn's powdered cheek.

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Bill/SFNM

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Re: WFO Interior Height
« Reply #10 on: May 25, 2011, 01:42:17 PM »
How odd!  I was talking to the EarthStone folks about this very thing last week at the Chicago NRA.  The big oven they had on display (6000#) had a very high ceiling.  The guy countered with the fact that is is designed to cook all manner of food but the smaller ovens are lower and more conducent to pizza.  They seemed to know you Bill.

I'm not saying high is bad or low is good. I am saying a height requirement as a function of diameter is a fallacy. There is a delicate balance between all of the factors that include heat conducted to the bottom of the pie from the deck, heat radiated from the coals/fire to the sides and top of the pie, heat radiated down on the top of the pie from the dome and from flames arching along the dome, dough hydration, etc., etc. Getting all of these things just right so that all parts of the pie are cooked to perfection at the same time is a monumental challenge, especially for the small ovens in which temp gradients are more extreme. In my limited experiments with adjusting the distance between the deck and the dome in my oven, I've seen no benefit yet in baking the pie closer to the dome. Rotating the pie as it bakes and a quick lift of the pie to dome when necessary works just fine for the way I bake - a single pie at a time.

In a commercial setting where large numbers of pies are being pumped out with minimum fussing, I'm sure having the pie bake closer to the dome is very desirable, especially if the pie is relatively far away from the fire.

Chau, IMO the arching flames help concentrate a lot of heat in the dome which is mainly of benefit when the top of the pie needs a final blast. The way I configure my fire, the heat radiated from the coals/fire is the main source of heat for the sides and top of the pie.

PizzaPolice

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Re: WFO Interior Height
« Reply #11 on: May 25, 2011, 01:48:24 PM »
Quote
I'm sure having the pie bake closer to the dome is very desirable, especially if the pie is relatively far away from the fire.

Oh, I forgot.  Esposito was making just one at a time but he did place the pizza very close to the dome on the opposite side of fire.  The reflective heat charred on the dome (wall) side.
« Last Edit: May 25, 2011, 01:50:10 PM by PizzaPolice »

Jackie Tran

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Re: WFO Interior Height
« Reply #12 on: May 25, 2011, 02:01:50 PM »
Bill I only have had 2 bakes under my belt so I haven't paid too much attention, but do you find that the arching flames makes a difference to the top of the pie or not?  Could you get the same result by baking just an inch or two from the coals without or without the arching flames from above as far as the top of the pie is concerned?

Thanks,
Chau

Oh, I forgot.  Esposito was making just one at a time but he did place the pizza very close to the dome on the opposite side of fire.  The reflective heat charred on the dome (wall) side.

PP, that is very very fascinating.
« Last Edit: May 25, 2011, 02:03:28 PM by Jackie Tran »

Bill/SFNM

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Re: WFO Interior Height
« Reply #13 on: May 25, 2011, 02:24:13 PM »
Bill I only have had 2 bakes under my belt so I haven't paid too much attention, but do you find that the arching flames makes a difference to the top of the pie or not?  Could you get the same result by baking just an inch or two from the coals without or without the arching flames from above as far as the top of the pie is concerned?

Chau,

As I am want to say over and over and over and over again: every oven is different, every firing is different, and every stick of wood is different.

As far as my oven and the way I use it are concerned, flames arching across the dome are not a critical factor. In a single firing it is easy to try baking in 3 different scenarios:

1) Heat only from coals, minimal flames
2) Heat from both coals and flames from the side, minimal arching
3) Heat from coals and flames from the side, and arching from above

I really don't do #1 because I count on the flames to illuminate the pie so I can see what is going on. I could strap a flashlight to my head, but that would be altogether way too dorky.

Usually I'm baking with #3, but often I haven't paid enough attention to managing the fire and end up baking with #2. As you know, I'm not big on timing total bake times - I try to watch how the pie is reacting to the heat such as how long it takes for the edges to start to puff up and how rapid that expansion is and whether one part of the pie is cooking faster. I would say that there is little difference between #2 and #3 in this regard. If I have to lift the pie to the dome, I keep it there less time with #3.

If the oven is adequately fired, I try to bake as far from the fire as I can.

dellavecchia

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Re: WFO Interior Height
« Reply #14 on: May 25, 2011, 02:44:37 PM »
Oh, I forgot.  Esposito was making just one at a time but he did place the pizza very close to the dome on the opposite side of fire.  The reflective heat charred on the dome (wall) side.

There is a really interesting article on the Woodstone site by Enzo Coccia about how the classic placement of pizzas in a NP oven. They, too, are placed right up against the dome wall. It may be why NP ovens are soldier coursed, and then angled in - the "top" of the dome is very close to the pie towards the sides of the dome when cooked in this fashion.

http://www.woodstone-corp.com/cooking_naples_style_oven.htm

Chau - In regards to the flame size, try out some different approaches. More and more, since my oven is so much smaller there will be some differences in cooking technique. But a bigger oven is in the works!

John

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BrickStoneOven

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Re: WFO Interior Height
« Reply #15 on: May 25, 2011, 04:33:28 PM »
I could strap a flashlight to my head, but that would be altogether way too dorky.

BrickStoneOven

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Re: WFO Interior Height
« Reply #16 on: May 25, 2011, 04:36:36 PM »
Oh, I forgot.  Esposito was making just one at a time but he did place the pizza very close to the dome on the opposite side of fire.  The reflective heat charred on the dome (wall) side.

This is the way I find works well. The side dome is usually almost as hot at the center dome. So one side gets hit from the coals and the other from the wall. Then the flame over head helps with the crust coloration.

TXCraig1

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Re: WFO Interior Height
« Reply #17 on: May 25, 2011, 04:46:45 PM »
Oh, I forgot.  Esposito was making just one at a time but he did place the pizza very close to the dome on the opposite side of fire.  The reflective heat charred on the dome (wall) side.

I always assumed that Marco's 3.4 number had something to do with this observation. Specifically, if there a meaningful amount of reflected heat as suggested in the quote above (anyone?), there may be a mathematical basis for the ratio. If the dome is an ellipse (for simplicity, I'm ignoring the soldier course but the top of the fire is probably about at that level), then as the diameter/height ratio increases, the foci move toward the edge of the oven, and as the ratio decreases, the foci move toward the center. At a 3.4 d/h ratio, the foci are consistently about 82% of the distance from the center of the oven to the wall. Using a 50" oven as the reference, this is about -/+1" difference from the wall from 40" - 60" ovens.

I have no idea if this is right, but it makes intuitive sense that you would want to (i) have the fire and (ii) bake at about the focal distance to get the most even heat possible. This logic might also argue that small ovens should be a little taller than suggested by the 3.4 rule to move the focus in from the wall some (assuming you weren't making proportionately smaller pies). However, I also think I remember Marco saying 40" was the minimum size reccomended.

In the chart below, the blue line represents ovens with a 3.4 ratio. The numbers represent the distance from the center of the oven to the foci as a fraction of the oven radius.

CL
« Last Edit: May 25, 2011, 06:50:12 PM by TXCraig1 »
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Matthew

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Re: WFO Interior Height
« Reply #18 on: May 25, 2011, 04:51:04 PM »
This is the way I find works well. The side dome is usually almost as hot at the center dome. So one side gets hit from the coals and the other from the wall. Then the flame over head helps with the crust coloration.

Bingo!  I have found that using an fireplace grate on the fire side makes a big difference in heat & flame size from the increased airflow.

Matt

« Last Edit: May 25, 2011, 06:38:30 PM by Matthew »

Jackie Tran

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Re: WFO Interior Height
« Reply #19 on: May 25, 2011, 04:51:36 PM »
Bill, I realize all ovens bake a bit differently from one another.  Likely due to the difference in dome heights.    Thanks for detailing your different baking scenarios.  Really helpful for someone like me who likes all the details.

That's interesting that you guys are mentioning using the side wall as a heat source.  Just last night I was thinking for the next bake, I will have the fire closer to the middle of the oven instead of far left.  That will let me create a smaller oven within my oven sort of speak.  As of now, I bake 12" pies one at a time so I don't need the extra room in my oven.  I'll do this for the first few pies to continue learning about the NP style, then move the coals more left to bake my hybrid pies.

Thanks John, I plan to do just that.

Chau
« Last Edit: May 25, 2011, 07:15:18 PM by Jackie Tran »

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