Pizza burns in new cordierite

[ivowiblo]

Hi!

I have a modified countertop oven with a stone that goes to 850°F. I do neapolitan-ish pizzas and everthing is beautiful. except for the fact that the stone broke and I'm having a hard time finding a good replacement.

The stone is cordierite and technically I bought another one from the same manufacturer but the performance is too different. I also used a different cordierite with the same results:

- my old stone will get to 850°F and the pizza bottom will be beautifully charred with small spots.
- the new stones will get to 850°F and burn the pizzas like they are tranfsering too much heat at once. the pizzas will stick a bit and even make a seal between the dough and the stone, making the rest of the pizza to blow like a baloon. the end result is a bottom that is burned on the border an completely clear in the rest. dialing back the temp won't do the tricka as they will be too pale. it's an all or nothing situation.

the old stone is grey but used to be yellowish as the new one. it is also outworn: while the new one is super smooth, the old one is rough and porous (how much cordierite did I ate in the last years??)

making some experiments I tried to burn the new stone using a torch and in the places where I was able to put a lot of heat, it turned grey. don't know if there was a change in the material or what, nor know if it will do a difference. I also put the stone in a regular oven for a couple of hours just to see any changes (there wasn't any).

The only thing I did with the old one is to bake many many pizzas in my regular oven and to make a lot of pizzas in the counter top oven, but don't remember having this issue not only once. but for sure I didn't start cooking at 850°F so maybe something changed with time and temperature. IDK

Any idea of what could be happening? Any advice? I'm trying to see if there's a way of season it but everything I found makes no sense (like putting oil in it)

Thanks!

[munselln8]

Not a cordierite expert by any stretch but my initial suspicion is that it is simply the "unseasoned" nature of your new stone. I recall that both of my stones were more difficult to work with when brand new. Wetter doughs would stick and I even had the "bubble phenomenon" once. My first thought is to just keep baking on it. If you bake any bread loaves directly on it, that helps too. Theoretically, once a bunch of oil gets in those microscopic crannies...maybe it will not burn the bottom??! Good luck!

[mosabrina]

850F is too hot for cordierite. Pizzas stick at those temps. I like my bottoms dark and 800-820F is pushing it.

Cordierite does not need seasoning. In all of the ovens I have my cordierite is factory color at all times because I always burn it off after each bake.

[nanometric]

Cordierite does not need seasoning. In all of the ovens I have my cordierite is factory color at all times because I always burn it off after each bake.

I've had a cordierite stone for nearly 20yrs and its color hasn't changed at all, apart from a few dark stains. I have not heard of a color change to gray - maybe OP's plate is not cordierite?

[Timpanogos Slim]

I would agree with the sentiment that above 750f or so, cordierite is more conductive than you really want. Fibrament or biscotto will give better results at neapolitan temperatures.

Stones get stained. I'm told by a friend who is a ceramics nerd that at about 1200f free carbon oxidizes directly to co2. Which explains how clean the cordierite in my outside oven got when i overheated it by a lot.

My folks' cordierite stone is about 35 years old and is still basically the same color, despite having absorbed an entire pound of butter in the mid 90's. Was a bit smoky for a while after that incident. 

[ivowiblo]

Thanks for your answers. I solved the issue!

so the big difference between my old cordierite and the new one is the texture. the old one was more rough due the use while the new one has a super smooth surface. so I brushed it with a metal brush and now it work lke a charm, supporting 450+°C

hope this helps someone

[nanometric]

I brushed it with a metal brush and now it work lke a charm

Glad it's working...and surprised a metal brush would have much effect on cordierite, which is much harder stuff than most metals. What type of brush did you use?

[Ischia]

What is the weight of the old stone compared to the new stone? Are the dimensions all the same?

[ivowiblo]

Glad it's working...and surprised a metal brush would have much effect on cordierite, which is much harder stuff than most metals. What type of brush did you use?

I'm attaching a sample picture of something similar to what I used

What is the weight of the old stone compared to the new stone? Are the dimensions all the same?

about the same. in fact, I bought it to the same manufacturer. the key difference is that the old one was super rough from the usage. now that I corred the new one, it performs superb.