An Open Call to Ceramic Engineers- Reverse Engineering Biscotto di Sorrento

[Tscarborough]

OK, I just talked to my contact at W-G, the vacuum process is used to reduce the air entrainment.  I also asked him about slabs, but that is not something they have plans to do, although he does stock 6x12x1-1/4 firebrick which will work nicely for my next project.

[Tscarborough]

Out of curiosity, I ran our numbers for firebrick last year and we sold nearly 100,000 fire brick.  That is a lot of fireplaces for somewhere where it doesn't even get cold!

[Tscarborough]

Here is for tufa:

http://books.google.com/books?id=51tphaprJTgC&pg=PA18&lpg=PA18&dq=tuff+physical+properties&source=bl&ots=gtBN4xrosl&sig=fdY7XNSb1Pm0APR-bWry3Sd9xcc&hl=en&sa=X&ei=OikuUa7pI4mm8gSf3IH4Dw&ved=0CEcQ6AEwAg#v=onepage&q=tuff%20physical%20properties&f=false

It looks like the Thermal Conductivity is between .2 and .3

[Serpentelli]

Why?  What positive do you see from a lower conductivity at the cost of strength?  I cook on these at traditional Neapolitan temperatures and get traditional Neapolitan results.  I see no positive out of an even lower conductivity.  With my experience and the data I now have on these If I could get them in larger slabs I would take them over Biscotto any day. 

I agree, I don't see anything out of the ordinary, but again, we have data from a major brick and tile laboratory at a major university that directly correlates to every cooking experience I have on this material.  For a couple years I have been baffled by people complaining about their firebrick hearths be too hot and burning while mine worked perfectly.  Now it all makes sense. 

Jeff,

I would love to see a picture of the interior of your oven, especially the cooking surface. Although another WFO is decades away, I'd like to know that I have the most suitable material when I do eventually build one down the road!

Thanks,

John K

[scott123]

Why?  What positive do you see from a lower conductivity at the cost of strength?  I cook on these at traditional Neapolitan temperatures and get traditional Neapolitan results.  I see no positive out of an even lower conductivity.  With my experience and the data I now have on these If I could get them in larger slabs I would take them over Biscotto any day.

Jeff, I'm not willing to trade conductivity for strength.  IF a particular chunk of Biscotto does actually clock in at .3 and will last, in a commercial environment for as long as a couple years, then I want that in a domestic option.

Now, bear in mind, my intentions go beyond Neapolitan oven owners.  It sounds like your W-G bricks could very well be the perfect domestic solution for John Q. WFO owner.  As far as deck ovens go, though, I have no idea that I'd ever find someone that needs .3, but if I can get a durable .3, I want it.  A few years back, I thought steel would be more conductivity than I'd need, and, more recently, I thought aluminum's conductivity was most likely way too high, but now I see both of these materials very differently.  As I consider .3, a part of me is saying that's ridiculous low and would most likely have no deck application, but... another part of me says 'you never know.'

Now that I see Tom's reference about Tuff coming in, on it's own, at .2 or .3, I'm pretty certain that .3 biscotto is a pipe dream. At this point, I'm not holding out much hope, but, if it turns out durable .3 can be done, I want it.

Btw, while we're talking about deck ovens, the best deck oven on the market, the Marsal MB, takes the top position because the low conductivity of the fibrament decks allows it to be be run at hotter temps while still maintaining good balance.  The W-G bricks have even lower conductivity than fibrament, and, since you're using them with direct flame, they are most likely far more thermally durable as well.  I, like you, would like to see these in larger sizes, but, other than that, these could easily blow fibraments out of the water and be the cornerstone for the next ultimate deck oven.

[Tscarborough]

FYI, I have replaced fibrament panels in a deck oven with W-G split firebrick and the owner really liked it.

[scott123]

FYI, I have replaced fibrament panels in a deck oven with W-G split firebrick and the owner really liked it.

That's sweet, Tom.  Here I am thinking about doing it, and you've already done it.

[shuboyje]

Btw, while we're talking about deck ovens, the best deck oven on the market, the Marsal MB, takes the top position because the low conductivity of the fibrament decks allows it to be be run at hotter temps while still maintaining good balance.  The W-G bricks have even lower conductivity than fibrament, and, since you're using them with direct flame, they are most likely far more thermally durable as well.  I, like you, would like to see these in larger sizes, but, other than that, these could easily blow fibraments out of the water and be the cornerstone for the next ultimate deck oven.

Once you get to certain point this just becomes to inefficient to be a commercially viable option.  If an oven needs a stone with the same conductivity as Tuff, which is used as an insulator(obviously not a good one), isn't this a case of the wrong oven for the job?  Putting massively oversized burners under and stone with low thermal conductivity all in the goal of getting a heat balance with more heat on top seems like a mess.

[Tscarborough]

They do not use the tufa as a block, they use it as an aggregate, along with other materials so that it is denser and has a higher modulus of rupture, better abrasion resistance, and (probably) a lower thermal coefficient of expansion.  The mix also would probably tend toward the higher end of thermal conductivity I would guess, because of the cementious material used (volcanic pozzolans).

[shuboyje]

So Tom, just to sum up this conversation.  If someone wanted to produce a Biscotto like product domestically, I'm guessing they would start with fly ash and lava rock?  That I would have never guessed, lol.

[Tscarborough]

Pretty much.  I have fly ash and access to a different type of tufa, maybe I will make a mix.