Granite as a cooking surface

[Andrew Beal]

Hi

Has anyone uses a slab of granite for the floor of their oven? I was thinking of laying common red bricks ontop of my concrete hearth with a layer of sand then the grannite slap on top. Fire Bricks are NZD$6.50 each over here and I have a piece of grannite big enough to cover the floor of the oven. I picked up about 60 second hand fire bricks for NZD$3.00 ea (Not enough). Has anyone made an oven using a combination of Fire Bricks and red clay type bricks? I was thinking of using the fire bicks for the top portion of the dome and the common red bricks (approx 60 years old and I have about 1600) on the bottom half of the dome. Do you think there maybe an issue with this. i.e different thermal expansion rates of the bricks causing cracking?

Your help is appreiciated
Cheers Andrew

[cynon767]

Originally Posted by Andrew Beal

Has anyone uses a slab of granite for the floor of their oven? I was thinking of laying common red bricks ontop of my concrete hearth with a layer of sand then the grannite slap on top. Fire Bricks are NZD$6.50 each over here and I have a piece of grannite big enough to cover the floor of the oven.

I have read about granite being highly unstable when exposed to heat and flame; apparently it pops, flakes, cracks, and even explodes under high heat. Blowtorches are used to create the look of "rough hewn" surfaces by heating the surface until pieces shatter away. Avoid.

Be sure to use as much insulation below the cooking floor as possible. Sand and brick don't count. Rather than layering concrete slab\brick\sand\granite hearth, consider concrete slab\insulation\brick hearth.

I picked up about 60 second hand fire bricks for NZD$3.00 ea (Not enough). Has anyone made an oven using a combination of Fire Bricks and red clay type bricks? I was thinking of using the fire bicks for the top portion of the dome and the common red bricks (approx 60 years old and I have about 1600) on the bottom half of the dome. Do you think there maybe an issue with this. i.e different thermal expansion rates of the bricks causing cracking?

The difference in expansion might be serious. I used 2 different firebricks, both from the same manufacturer, both nominally medium duty, just slightly different in texture and color, and had a crack through one of the bricks after my first few firings. I would shy away from using different bricks in the dome. You could use the firebricks for the floor, which will take alot of abuse with food sliding across it, and use the commons for the dome.

[tfasz]

I have heard of a number of folks using Soapstone for a cooking surface. It is also commonly used in fireplace hearths. Not sure it would save you any money though.

[dmun]

Soapstone is silly expensive: It makes NZ firebrick look like a bargain.

[blackjimmy]

I'd be pretty worried about it cracking under the heat. Also as far as I know granite is very impervious to liquid, which is one of the reasons it's so ideal for a kitchen worktop. I think a better surface is a very porous one like brick or terracotta which actually sucks the moisture away from the dough as it cooks, making a crisp crust. But I know some people on here have used successfully used soapstone which is even less porous than granite, so what do I know!

Personally I would save a nice piece of granite for a pizza preparation work-surface next to the oven (granite is great for dough and pastry prep because it stays cold and dough doesn't stick to it easily), and anyway it seems too nice to use for inside an oven!

If you do decide to go with the granite though, post your progress on the forum. It'd be very interesting to see how it worked out.