Soapstone vs Firebrick ??

[luca]

Re: Soapstone vs Firebrick ??

Interesting discussion! As it turns out, I just finished a barrel vault oven with a 18"x24" soapstone slab in the center of the cooking floor surrounded by firebrick, with an overall cooking surface of 24"x36". This is my 4th-5th cooking experience, and here's how it works; the soapstone slab has an enormous temperature gradient, measuring 868F at the edge of the fire, to 770F about 4 inches away from the fire, all the way down to 540F at the flue. Meanwhile, the firebricks on the edge of the soapstone range from 660F at the fire's edge, to 660 F 4 inches from the fire, to 560F at the flue. This means that I burn the bottom of my pizzas if I put them anywhere near the fire, so I have to cook them under the flue (650F seems to be the ideal floor temp). I have also used a wire grid under the pizza closer to the fire, and this prevents burning and lets the top cook faster, at a higher temp. Also, my soapstone cracked when I left the new fire on its surface, so now I start the fire and immediately move it to the back of the oven to avoid this problem. Since i live in Vermont where soapstone is cheap ($10/sf) I thought I'd try it, but I agree with those of you who point out that firebricks maintain an even temperature and are easier to maintain. I've considered removing the soapstone, but now that I know how to work with it, I'll keep cooking for awhile and see if there are any major benefits. Overall though, I'd advise staying with firebricks!

[buckeyebreadman]

Re: Soapstone vs Firebrick ??

Too far away for me, but a very kind gesture nonetheless. Thanks.

[skulptor007]

Re: Soapstone vs Firebrick ??

Hi there,

I'm a newbie to the site and pizza ovens,but I have been specializing in Soapstone since 2003 and have been a stone sculptor/tilesetter/stone fabricator since 1987.
I'm not sure if I can name my business, but I would be willing to donate some remnant soapstone pieces( mostly smaller pieces that could be made into bricks but I have a couple larger pieces that would make up a floor) to those sincere in educating themselves with it as long as they share their findings with the group here and dont use the pieces for profit,as I'm interested in building ovens using soapstone in the best capacity, hearth floors,walls or domes etc.

Those of you interested pm me.

Ciao!
Greg

[scott123]

Re: Soapstone vs Firebrick ??

Anyone interested in a soapstone oven floor might want to connect with windage in the commercial area and ask about his experience with his WFO oven floor.

Chris

I know people successfully using slate in ovens. Jamie Oliver has been known to recommend slate as a baking stone. Slate has a long history in oven use. This doesn't mean that slate is a viable choice for baking. It has a ridiculously low resistance to thermal shock.

Soapstone will always be a gamble. Windage might install a piece that lasts them a few hundred years, while someone in this forum might install a piece that lasts them a week. Mother nature has no quality control.

[SCChris]

Re: Soapstone vs Firebrick ??

John,
Re. the thermal break;

I did try the break with the soapstone and could have kept the SS in the entry area. The break made a substantial difference with the entry stone temps and the overall duration of heat retention. The only reason I swapped to granite was the warmer color of the granite was more in step with the overall area not for any functional reason. I was more comfortable with the soapstone at 3cm and that SS is not porous granite is more porous and needs to be sealed in a kitchen setting. I understand that oil and wine can stain and be noticeable in certain types.

Chris

PS I know I included a graphic somewhere but don't find it at the moment. What I did was to rip a piece of rigid insulation in a "L". The high end of the L sits against the firebrick floor of the oven, the bottom of the L is a platform for the entry area granite floor. The L provides a 1/2 inch break between the oven and entry stone. The material is slightly resessed to avoid any contact with any food, pans or implements. Wlively uses a inverted V to minimize the gap at the door and I don't remember that he uses anything but ash as the filler material.

[GianniFocaccia]

Re: Soapstone vs Firebrick ??

Buckeye,

Harbison-Walker (anhrefractories.com) sells 1'x2' firebrick tiles. They have distribution centers (might be open to the public like their Los Angeles facility) in Cleveland and Cincinnati.

Chris, I know you experienced an improved heat loss when you switched your entryway soapstone for granite. How is your thermal break configured and did you have this in place with the soapstone? The reason I ask is I have sourced a piece of 10-gauge stainless steel for the entryway floor but am afraid it will leak too much heat without a proper break. Still trying to figure this one out.
John

[SCChris]

Re: Soapstone vs Firebrick ??

The single seamless floor seems to be the major motivation for looking at Soapstone. I have a brick floor and don't find the seams a problem. I used 2" of CalSil rigid insulation board and used Whitaker firebricks directly on top of this so the floor is dead flat. Of the three varities of bricks available Whitaker seemed to be the most consistent at my brickyard. I replaced my brick entry with granite and like that this area resists staining and cleans up easly. This change allowed me to incorporate a heat break in the floor between the oven and entry.

Chris

[buckeyebreadman]

Re: Soapstone vs Firebrick ??

The cost is making me think twice.
Is there a supplier for larger slabs of Firebrick? My main reason for wanting Soapstone is the seamless floor.

[SCChris]

Re: Soapstone vs Firebrick ??

Anyone interested in a soapstone oven floor might want to connect with windage in the commercial area and ask about his experience with his WFO oven floor.

Chris

[scott123]

Re: Soapstone vs Firebrick ??

Chris, I, too, have a soapstone slab in my oven that I've been using for four years that has served me well, but the environment of a home oven is not the same as the direct flame environment of a WFO. While I think there are better materials for a home oven stone than soapstone, my comment above only relates to WFOs.

With the additional thermal stress from a direct flame, the cracks you might see in home oven will be fractures in a WFO.

Regarding using a cracked or a fractured stone, I think that is an especially bad idea. Veins are rarely perfectly straight faults, and when a stone cracks/fractures, there's no guarantee that the remaining edges of the stone will still be unharmed or that all damage will be visible. Any kind of crack/fracture introduces a high potential for shards/chips. If a chip of stone ever made it's way into an undercrust and you/your guest bit into it, it would wreak havoc on teeth.

I think the odds are highly in your favor that a shard won't make into your bread/pizza, but do you really want to take that chance?

Natural materials have too many potential variables to be viable in ovens. I'm well aware that some of these stones have a long history in this regard, but, thankfully, we no longer live in the dark ages and have modern materials whose consistency can be thoroughly engineered.

If you want to roll the dice, go for it, but I value my money, the quality of my pizza, my safety, my teeth and my piece of mind.

[SCChris]

Re: Soapstone vs Firebrick ??

Soapstone a natural material and is a blend of different minerals and because of this soapstone can be veined, this veining is not ideal for a WFO. Soapstone is used in some pizzerias, some of these burn coal and cook pizza at uber-high temps 900F+.
That Soapstone is not ideal for pizza is not necessarily true.

Defining pizza is like defining motor vehicles, the breth of pizza is wide to say the least and so the ideal methods and tools for cooking are also wide. If you want to transfer WFO heat Soapstone is superb at doing this. Soapstone is stable under WFO heat and non-porous so it’s easy to clean and so it’s ideal for countertops. It’s dense and holds heat well so a smaller volume will hold more heat than a brick, high thermal mass.

I‘d love to have a soapstone floor in my oven, but I don’t. I tried a soapstone entry but aesthetically I was better with granite. I have to agree that cost can be a huge turnoff, especially for us home builders but like you pointed out, not always. Conductivity is reported to be a problem with bread, I’m not a volume baker so don’t know, but if I were I think learning and knowing the WFO and bread doughs would likely make the Soapstone floor a moot point. Misidentification is huge, and part of this is that Soapstone varies from fingernail soft to medium hard. Obviously granite and marble is not at all like soapstone and using it in a WFO would be a disaster.

I think it’s a very cool material and as long as you can get it at a good price and it’s fairly homogeneous, go for it. I’ve seen Soapstone firebricks, and like firebricks these can be replaced if needed.

I had a soapstone pizza stone in my home oven for 2 or more years and baked hearth bread on it weekly. It has some cracks it but it has never failed. I also need to point out that where the material cracked is where it is veined. If it was a floor in a WFO these cracks would be less significant than the brick joints in a normal floor. I also want to point out that the additional mass in my kitchen oven made cooking ox tails and other braised meats a snap.

If someone has access to it and the desire to use it, go for it..

Chris

[scott123]

Re: Soapstone vs Firebrick ??

For anyone still thinking about buying soapstone to use as a hearth...

As you can see from the beginning of this thread, 2 years ago, I was a big fan of soapstone, but, over time, my feelings have changed. Dramatically. Soapstone is not a viable choice for use as a hearth in a wood fired oven.

Price

Soapstone is heavy and takes a lot of fuel to transport. The farther from the source, the more money is spent on fuel. It's also quarried in very few parts of the world. Here on the East Coast of the U.S., we get our soapstone from Brazil. In the U.S. very few distributors deal with the quarries directly. You have one or two wholesalers that take the stone off the boat and then many other smaller shops further inland. If you can deal with a distributor, the price tends to be reasonable ($10ish/sq. foot for remnants), but if you live further inland, you'll see a considerable markup. The wide disparity the members of the forum are seeing in prices isn't about honest/dishonest sellers, but geography/middlemen.

Even at the lowest price you can find ($10/sq. foot), it's still going to be more expensive than firebrick.

Conductivity

As has been previously discussed, soapstone's conductivity makes it less suitable for bread/pizza because the bottom tends to burn before the top. You can take steps to avoid this, but it's extra work. Soapstone's biggest strength is in settings where high hearth temps cannot be reached and dome temps/hearth temps are independently controlled (such as home ovens). For a WFO, a high enough hearth temp is rarely an issue.

Misidentification

Out of maybe 50 people that I know who have purchased soapstone for baking use, at least 10 were sold a different kind of stone and told it was soapstone. I've seen both granite and marble being passed off as soapstone. The wholesalers have no problem identifying it because it's all they deal with, but the smaller distributors, who deal with a much wider variety of stones, can frequently have identification issues. Add to this the fact that there are varieties of soapstone itself that are less suitable for oven use and you're complicating things even further. Marble and granite have extremely little resistance to thermal shock, making oven use a dangerous proposal. If someone's installing what they think is soapstone for a counter, but end up with marble, that's one thing, but using marble in a direct flame setting could have disastrous consequences.

Quality Control

Mother Nature has horrible quality control. When she deposits sediment over thousands of years, she's not thinking "how can I create a thermally durable material?" Even if you get lucky and get a 'real' piece of soapstone, it's still going to be a crap shoot. It can have visible or invisible fractures/weak points. It can have less conductive areas and more conductive ones. In Scandinavian countries, soapstone has a long history of oven use, so perhaps there's oven builders there that can look at stone and predict how it might stand up to oven use, but, for the rest of us, we're just rolling the dice.

So, summing up, stick to firebrick- an inexpensive, easy to identify, appropriately conductive (for a WFO) hearth material that's actually been engineered for direct flame use. The right tool for the job.

[buckeyebreadman]

Re: Soapstone vs Firebrick ??

Went to another Granite supplier.......$68/ft. YIKES!!!

[Mike D]

Re: Soapstone vs Firebrick ??

You can get big pieces of fire brick if your looking for less seams. They are really heavy but then you only have to put them down once.

-Mike

[david s]

Re: Soapstone vs Firebrick ??

I hear ya, DJO. I stopped by a steel company today that sells cutoffs to get a price for a piece (18"x26.5") of 10-gauge 316 restaurant-grade stainless steel for my entryway floor. To have it cut and two flanges bent 90* on the ends, I was quoted $142 (less tax). That comes out to $42.90/sq'.

Everyone wants to be a millionaire.