Author Topic: An Open Call to Ceramic Engineers- Reverse Engineering Biscotto di Sorrento  (Read 14458 times)

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Offline TXCraig1

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I've cooked lots of Neapolitan pizzas on WG at 0.6 @ ambient temperature.  I'm sure they go up a bit as the temperature rises.  For my oven designs I'm pretty confident 0.69 @ 600C would be adequate.

Have you tried baking on a piece of Fibrament in your oven at 600C?
"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza."
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Offline shuboyje

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Craig,

My post last night was clear as mud.

What I was trying to say is WG low duty buff firebricks have a thermal conductivity of 0.6 when measured at ambient temperature.  I think it is safe to assume that at 900F+ the conductivity has risen a bit.  I've baked a lot of Neapolitan pizza on this material and am happy with the results.  I think a Castable material at 0.69 thermal conductivity measured at 600C would be VERY similar to the WG bricks, if not a little less conductive. 

Have you tried baking on a piece of Fibrament in your oven at 600C?

I've never purposely baked at 600C, but the few times I have it hasn't gone well.  Once I oil fired my first oven with an experimental oil burner running on waste cooking oil.  Pizza burned to charcoal in no time.  The other time was a few months ago in my coal oven when I go it crazy hot to do Neapolitan.  That time I was on top of it to not burn the pie, but the drying effect of the coal at that temperature produced a very odd pizza.

Fibrament has never entered the equation for me due to it's inability to operate in direct contact with flame.  That obviously won't fly in a wood oven.  I might be able to get away with it in my coal oven, but that is so small and square so doing a brick floor was a no brainer compared to an experimental, expensive, custom floor.
-Jeff

Offline TXCraig1

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Right after I posted, I jumped in my truck. As I drove off, it hit me what you were saying.

In my oven at 600C on the deck, you need to dome the pie after about 20 seconds. 15 seconds later it's done.
"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza."
Craig's Neapolitan Garage

Offline sub

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I was talking to an owner of a four grand mère F 1030C about the benefits of a Biscotto floor, and He put terracotta baseboards as a temporary mod to tryout.

He is quite happy with the result,

before that he was burning the bottom of his pies when the floor temperature was above 750-770°F.
« Last Edit: August 09, 2014, 06:45:21 AM by sub »

scott123

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Terracotta tends to be pretty low in conductivity, but it's also not very resistant to thermal shock, so I don't see it surviving all that long.

Offline shuboyje

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I was talking to an owner of a four grand mère F 1030C about the benefits of a Biscotto floor, and He put terracotta baseboards as a temporary mod to tryout.

He is quite happy with the result,

before that he was burning the bottom of his pies when the floor temperature was above 750-770°F.

AND those terra-cotta tiles are not easily available in the US.  I've worked on renovation project of old buildings with terra-cotta walls,  structural terra-cotta in the US is very hard to get and expensive. 

If anybody knows otherwise I'de love to know, they do look like a really nice material to build a neapolitan vent out of like the Italians do.
-Jeff

Offline stonecutter

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I've been looking for years too, for other masonry projects. I do have a couple companies that may do it, I'll check when I'm back in SC on Monday.
http://oldworldstoneandgarden.com/


When we build, let us think that we build for ever.
John Ruskin

Offline Iowamcnabb

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I've read the thermal conductivity of cordierite is 3 w/mk   Does this sound right?  I've not had burnt bottom problems on my makeshift oven using 1 and 1/4 cordierite?
« Last Edit: August 15, 2014, 11:35:30 AM by Iowamcnabb »

Offline TXCraig1

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I've read the thermal conductivity of cordierite is 3 w/mk   Does this sound right?

Yes, that is correct.
"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza."
Craig's Neapolitan Garage


scott123

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Cordierite can range in conductivity, depending on how it's manufactured.  It can range from 1.5 w/mK to 3 w/mK.  I have found that the lower conductivity generally corresponds with lower density cordierite.

Offline TXCraig1

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Please post an example of a cordierite stone/shelf meaningfully under 3 W/mK.

BTW - the thermal conductivity of Cordierite is 3.0 W/mK. While you may be able to structure a product in such a way that the conductivity of the product is lower, the conductivity of Corderite doesn't change.
"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza."
Craig's Neapolitan Garage

Offline Iowamcnabb

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Why are those of us using cordierite not burning the crap out of the bottom of our pies at 3.0 while others with less conductive bricks struggling?

Offline TXCraig1

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Why are those of us using cordierite not burning the crap out of the bottom of our pies at 3.0 while others with less conductive bricks struggling?

My guess is you don't have enough mass in the deck for it to be a problem. How hot is your deck before and after baking?
"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza."
Craig's Neapolitan Garage

Offline Iowamcnabb

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My guess is you don't have enough mass in the deck for it to be a problem. How hot is your deck before and after baking?

When I just had one 5/8 inch stone the pies would need to be domed after 15 seconds or they would burn.  When I placed a second 5/8 stone on top they didn't have to be domed at all launching at 800 to 850.  The deck is 700 or so 30 minutes after I've finished. 

Offline TXCraig1

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I meant before and after baking a pie. What is the temp when you launch and when you retrieve the pie - i.e. how much does the temp drop?
"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza."
Craig's Neapolitan Garage

Offline TXCraig1

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When I just had one 5/8 inch stone the pies would need to be domed after 15 seconds or they would burn.  When I placed a second 5/8 stone on top they didn't have to be domed at all launching at 800 to 850.  The deck is 700 or so 30 minutes after I've finished.

You have a heating element below the bottom stone, right? Sounds like the heat was passing quickly through it with one stone and burning the pies. Adding a second stone doubled the thickness which in and of itself halves the rate of heat transfer and also introduces an air gap which would drop the conductivity of the system (stone-air-stone) dramatically as compared to stone alone.
"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza."
Craig's Neapolitan Garage

Offline Iowamcnabb

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I generally launch the first pie at 820 or so and usually launch the second pie 5 minutes after the first at about the same temperature.  I'll check the deck this week right after the first pie comes out. 

I only have the one top element.  I decided against a bottom element in favor of really good insulation. 


Offline TXCraig1

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My guess is that the drop will be significant.
"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza."
Craig's Neapolitan Garage

Offline sub

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I' really happy with my terracotta stone in my G3Ferrari, no burn bottom or bad taste even at 970°F

My homemade clay stone is drying well.

Offline stonecutter

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Sub, what was your mix design for the tile?
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Offline MotoMannequin

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My guess is that the drop will be significant.

Jumping into an old thread here but I believe Craig is correct Cooking on a BGE with a stack of Cordierite stones over 1" thick, doing 2-minute pies with the stone in the 750ºF range, I found that I had to let the stone warm up for a few minutes after pulling a pie off, before it was hot enough to cook the next. Conductivity doesn't matter so much if there's not enough mass to hold temperature.

I'm in the planning stages for a low-dome brick oven in my back yard, and this thread has been a fantastic read. Thanks Sub!

I think I have answered all my burning questions, except for floor material, which I'm pretty stressed about. The our local building supply is unable or unwilling to provide any data on their firebricks. They're even trying to convince me to build out of clay bricks since that's what all their contractors do. The firebricks I think are fine for the dome, but I won't use them as floor material unless I can verify the conductivity somehow. Any suggestions? Heat up a brick and measure the rate of cooling? Does the weight of the bricks tell me all I need to know?

At this point I have no faith in the floor tiles that Forno Bravo sells.
« Last Edit: October 14, 2014, 01:42:00 PM by MotoMannequin »

Offline Tscarborough

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Use low duty firebrick like those manufactured by Whitacre-Greer in Ohio.

Here is their data sheet:

http://www.wgpaver.com/wp-content/uploads/2013/05/Product-Data-Buff-Firebrick.pdf


Offline Donjo911

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Not to confuse the matter.  This may not even be relevant however,  I was watching one of those Ancient Civilization shows. In this case, it was the Roman Empire. The explained how the Romans engineered aquaducts across long uneven terrain; building combounds and technique to assemble and upright giant columns and facades, etc.,  They spent a fair amount of time explaining the geology of Italy, the use of Volcanic ash, and other (I wish I could remember) Volcaninc soil, due to it's mineral make up and so on.  When I saw it - It sounded like what I have read is "Biscotto di Sorrento"  I remember them saying that it was the genius of the Romans along with the good fortune of being in a volcanic area that allowed them to develop these kind of "technologies."  I'll see if I can find it but they had a British Historical Geologist duplicate the method of creating the Romans' light but very strong materials - perhaps there are some bread crumbs to follow there?  Or is it Pizza crumbs?  I'll see what I can find.  I watch a lot of History, Nat Geo, etc. It was assuredly on one of those channels. 
Cheers,
Don
I have done wrong.. but what I did, I thought needed to be done.

Offline MotoMannequin

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Use low duty firebrick like those manufactured by Whitacre-Greer in Ohio.

Here is their data sheet:

http://www.wgpaver.com/wp-content/uploads/2013/05/Product-Data-Buff-Firebrick.pdf

Thanks TS. Looks like they have a dealer in San Rafael. I'll contact them.

Offline Neopolitan

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Re: An Open Call to Ceramic Engineers- Reverse Engineering Biscotto di Sorrento
« Reply #99 on: December 31, 2014, 03:38:57 AM »
Sorry Larry for answering this late ;D

but have You seen the firing  and operating temps of that white greer stone? 2000 degrees that is white hot.

Will reduce the backing time of the pizza considerably >:D

I don't understand that in this thread, the only One who was not just theorizing But triyng to produce something really engineering was not taking serious ???

I have A long But dusty relationship with ceramics, that Because of my build of a cob WFO is refired.

And as I am Very interested in Ancient engineering. I have and still study Roman architecture.there are Some references to the Roman concrete and mortars fascinating stuff, and without them having the natural recourses in their backyard (Campania) at Mt Vesuvius so they could start this revolution in building materials like sea waterproof concrete and fire mortars, I am convinced we wouldn't be discussing The Neapolitan Pizza on the web.

Engineers have failed recreating The Roman Pozzalano concrete, But Biscotto is still in production in Italy so can created still.

I know there is Clay, Lime-Chalk, Sabbia or Volcanic sand and ash,But also the choice of the particular river sand and water is important!

I would love to hear from that sole experiment by Sub?