#21  
Old 01-09-2012, 12:40 PM
david s's Avatar
Il Pizzaiolo
 
Join Date: Mar 2007
Location: Townsville, Nth Queensland,Australia
Posts: 4,511
Default Re: Soapstone vs Firebrick ??

only just picked up on this thread.
We used to use soapstone as a material for sculpture, it is the softest stone you can get. Also known as talc stone it sands really easily producing talcum powder.

Regarding thermal conductivity, its reciprocal (direct opposite) is its insulating capacity (R value) so if you want to know how good an insulator something is then it is easier to look up its thermal conductivity.

Soapstone having a higher thermal conductivity than firebrick should therefore lose its heat faster than firebrick, requiring more underfloor insulation.

I believe that the porous nature of firebrick has a lot to do with its superior cooking ability. In the case of pizza and bread this porous nature sucks any moisture from the bottom of the dough resulting in a crispier crust, unlike the soggy crust you get if you cook pizza on a tray. Soapstone is not a porous rock so presumably you don't get this advantage.I would think it would result in less crispy crusts.
Reply With Quote
  #22  
Old 01-09-2012, 01:23 PM
Il Pizzaiolo
 
Join Date: Jun 2009
Location: So. Orange County, CA. USA
Posts: 1,155
Default Re: Soapstone vs Firebrick ??

My take on the porousity and crust is a bit different than David's. Right or wrong in logic, my feeling is that the stone and the crust create a layer of active steam that escapes out under the pizza, out the top and into the nice little bubbles in the crust, and in the end you get a crispy crust.

I used a 3cm soapstone pizza stone in my oven for a couple of years, mostly to bake bread on but also for the ones and twos pizzas from time to time. What I found is limited to the ability of my kitchen oven to reach more than 550F, but crispy crust wasn't really a problem.

What I found to be the culprit for soggy crust was over topping with wet sauce and cheese.. I feel that the advantage of the soapstone is getting the temps even on the floor and really being able to slam the heat into the pizza dough. The soapstone can hold more heat per weight and transfer more heat faster than the brick but brick is cheaper and twice the thickness 6cm vs 3cm.

I feel that in an oven where the volume of pizzas is high, the soapstone can heat charge faster than the brick and recover faster to the ideal pizza temps. In most of our ovens volume of pizzas out of the ovens isn't really the problem. The value for our ovens would be getting the heat into storage faster and getting an even floor temp. We might also expect to see a faster evening out of temperatures within the oven so, for instance, when you prep the oven for bread the amount of time to reach an environment where the dome and floor are close to the same temp is decreased. We might also see that, since the floor is non porous, the bread is steamed more fully because this is one less surface absorbinbg the steam.

I've read that brick is better than soapstone for true bread baking, I'm ok with this if it's so. The statments about bread on soapstone are that the bottom cooks too fast relative to the top crust. I don't know and haven't seen any first hand information on bread on soapstone except what I've done and I'm quite happy with the results.

I'm sure that the quality of the pizza and bread is more a function of the cooks knowledge and the ingredients.

Just my opinion..

Chris

Last edited by SCChris; 01-09-2012 at 03:12 PM.
Reply With Quote
  #23  
Old 01-10-2012, 03:16 PM
GianniFocaccia's Avatar
Il Pizzaiolo
 
Join Date: Jun 2009
Location: Disneyland, CA
Posts: 1,312
Default Re: Soapstone vs Firebrick ??

Last summer I got the IR thermometer out and compared the readings from a piece of firebrick and a slab of soapstone just like the floor my oven is made out of. Both pieces of material had been baking in the sun since morning and it was probably 1pm and close to 90F ambient temperature. The termperature of the firebrick was 111F and the temperature of the soapstone was 134F.

I take this to mean that the soapstone will operate at a higher temperature given the same volume of heat-loading. Does the color difference (firebrick=peach, soapstone=black) contribute to the difference? Probably.

Until recently, I had never heard that soapstone has been regarded as a superior insulating material, but it kind of makes sense when one considers it is used in the Tulukivi soapstone heaters.

It was my belief that the reason soapstone is not an optimum surface (The Breadbuilders by Alan Scott) for baking bread is because it operates at a higher temperature (like my sun test) than firebrick and burn bread bottoms before the top cooks.

I will certainly be testing this theory once my oven is completed (whenever that is), but part of my testing will be with fire management to equalize the dome and floor temps in order to get a perfectly-cooked loaf of bread. If I find that the floor or dome hasa to be a different temp than the other, so be it. I am looking forward to reporting these results more than any other aspect of my oven.

PS: I have a normal 2.5"-thick firebrick 'subfloor' beneath my soapstone and will also be interested to find out how the floor temp curve compares to the dome curve as the oven coasts, and will report that as well.
John
Reply With Quote
  #24  
Old 01-10-2012, 03:38 PM
david s's Avatar
Il Pizzaiolo
 
Join Date: Mar 2007
Location: Townsville, Nth Queensland,Australia
Posts: 4,511
Default Re: Soapstone vs Firebrick ??

if the soapstone has a higher thermal conductivity than the firebrick, it would be expected for the temp to be higher. It would also follow that the higher thermal conductivity would translate to it being a poorer insulator. One would expect then for its temp to drop faster. It would be interesting if you could also test this with you IR.

Last edited by david s; 01-10-2012 at 03:49 PM.
Reply With Quote
  #25  
Old 03-07-2012, 05:13 PM
Apprentice
 
Join Date: Mar 2011
Location: Ohio
Posts: 152
Default Re: Soapstone vs Firebrick ??

While at my longtime Granite supplier this morning, I asked if he had any Soapstone.
Seeing the product, I wasn't so sure.....it looks like Granite (with veins in it)...is that normal?

I have some pieces of Soapstone at home (antique warmers of some sort) and they are more of a solid dark gray color...

any advice or comment would be appreciated....

OH....and for a piece 43" by 43" 3cm was $340.... a little steep....but the smooth, seamless oven floor would be Nice!

Last edited by buckeyebreadman; 03-08-2012 at 02:57 PM.
Reply With Quote
  #26  
Old 03-08-2012, 02:59 PM
Apprentice
 
Join Date: Mar 2011
Location: Ohio
Posts: 152
Default Re: Soapstone vs Firebrick ??

Anyone?.....
Reply With Quote
  #27  
Old 03-08-2012, 03:21 PM
Il Pizzaiolo
 
Join Date: Jun 2009
Location: So. Orange County, CA. USA
Posts: 1,155
Default Re: Soapstone vs Firebrick ??

Some veining is normal. It's my understanding; from the research I've done, that for our use, a darker more homogeneous material is best. Soapstone is not a single mineral but a blend of several. The darker material is mostly serpentine and is harder than the lighter colored talc. The reason that more homogeneous is good for us is that the talc is weaker and expands at a different rate and to a different degree than does the serpentine and so after some number of heating and cooling cycles it will crack. Cracking isn’t so bad if the sub-base of the soapstone is flat and if the cracks don’t interfere with food in and food out. I can’t comment on pricing but would say that with a bit of effort you should be able to find excess material from some kitchen counter job at a really good price, after all its leftover from a job that paid for the material outright.

Chris
Reply With Quote
  #28  
Old 03-08-2012, 03:28 PM
Apprentice
 
Join Date: Mar 2011
Location: Ohio
Posts: 152
Default Re: Soapstone vs Firebrick ??

The scarey thing is that this IS a piece of leftover! I was hoping for a deal but he wants almost $50 sq./ft.
So, if it is in fact just another type of granite or marble....wouldn't ANY kind of granite or marble work in a WFO?
Reply With Quote
  #29  
Old 03-08-2012, 03:45 PM
Il Pizzaiolo
 
Join Date: Jun 2009
Location: So. Orange County, CA. USA
Posts: 1,155
Default Re: Soapstone vs Firebrick ??

Other materials will break down due to the heat. I think you should offer them half and walk away if they don't want $. I like the idea of the seamless or minimally seamed floor but I haven't found my brick floor to be a problem. Where I found I appreciate not having the bricks is in the entry area. This area gets spills and staining from the oven being used but doesn't ever get hot enough to burn these off. I tried Soapstone and really like it in the entry but it wasn't quite the right color for my area so I switched to a granite that matches the other materials in my oven / patio area. The minerals in the granite would breakdown in a hury in the fires of the oven.

John, aka GianniFocaccia has used Soapstone spectaculary in his oven as has Windage. John states that he is looking to increase mass in the floor and distribute the heat evenly to the bricks below. No matter what reason, it is spectacular. John's is on it's way to being one the F1s of WFOs on the site.



Chris
Reply With Quote
  #30  
Old 03-08-2012, 03:54 PM
Apprentice
 
Join Date: Mar 2011
Location: Ohio
Posts: 152
Default Re: Soapstone vs Firebrick ??

Much thanks Chris..........I'll check out the others you mentioned and go from there...

Bill
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Soapstone Hearth GianniFocaccia Finding Building Materials 12 05-28-2011 11:44 AM
Soapstone floor - Advice Beron Finding Building Materials 15 05-25-2011 11:47 AM
Vent/flue/chimney of pure firebrick kebwi Tools, Tips and Techniques 7 06-08-2010 11:17 AM
Using Soapstone and possible applications fshead325 Pompeii Oven Construction 2 09-26-2009 02:57 AM
Firebrick rating? rtnaw Getting Started 10 08-09-2007 11:10 AM


All times are GMT -7. The time now is 06:02 PM.

Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
© 2006/10 Forno Bravo, LLC