Author Topic: Any Experience With Corderite? (Read 10384 times)

jefe · « **on:** May 14, 2007, 09:53:54 PM »

I am fairly new to pizza making. I am trying to decide whether to order a box of the Daltile Red Quarry Tiles or order a Corderite Kiln Deck.

My questions are
1. Are there different grades or types of corderite?
2. i.e. Would the corderite listed at the site below be safe to cook on?

Unfortunately I cannot post the link

to Sheffield Pottery but they have a 17" x 17" x 3/4" kiln shelf for $24

Thanks!

Pete-zza · « **Reply #1 on:** May 14, 2007, 10:23:29 PM »

jefe,

I believe this is the link you wanted to post: http://www.sheffield-pottery.com/Square-Cordierite-Kiln-Shelves-s/320.htm.

One of the few posts that I can recall on the forum on the subject of Cordierite shelves is this one:
http://www.pizzamaking.com/forum/index.php/topic,1488.msg13694/topicseen.html#msg13694
(Reply 21).

I know that Cordierite is a popular material for baking stones but don't have any specific advice on that material. I would call Sheffield and ask them the questions you posed. I would think that they have been asked those questions before.

Peter

jefe · « **Reply #2 on:** May 14, 2007, 10:54:54 PM »

Thanks Peter. I actually had seen that thread but did not come across any further information on cordierite. Most quarry tile users seem pretty enthusiastic about it. I know that some of the commercial ovens have cordierite decks so that's why I was interested in finding out. I'll give Sheffield a call and post what I can find out.

jefe · « **Reply #3 on:** May 15, 2007, 03:52:15 PM »

This was the reply I got from Sheffield:
"you can cook on a new kiln shelf. The downside is that they are designed to be poor absorbers of heat so not as good as say a pizza stone however much more durable than a pizza stone. Pizza stones are cone 6 or cone 10 stoneware so what you could do is cover a kiln shelf with a slab of stoneware clay ...fire the whole thing in a kiln and then you would have the ultimate cooker...
just a thought"

I wonder why they use this material in commercial pizza ovens?

November · « **Reply #4 on:** May 15, 2007, 04:18:10 PM »

Quote from: jefe on May 15, 2007, 03:52:15 PM

I wonder why they use this material in commercial pizza ovens?

Probably because you don't want the bottom of the pizza to burn before the top is finished baking. The goal is to bake top and bottom at the same rate. However, the specific heat capacity of Cordierite is actually pretty high at 1.465 J/g °C^-1, so although it conducts heat slowly, it can hold on to a lot of heat for its mass.

- red.november

jefe · « **Reply #5 on:** May 16, 2007, 08:38:27 PM »

So, this material would take a long time to heat up, but once it heated up it would stay hot for awhile?

If so, not sure if it's the best choice for use in a home oven.

November · « **Reply #6 on:** May 16, 2007, 09:10:09 PM »

Quote from: jefe on May 16, 2007, 08:38:27 PM

So, this material would take a long time to heat up, but once it heated up it would stay hot for awhile?

Rather than just saying it would take a long time to heat up, it might be useful to compare it to other well known materials. Stainless steel for instance, would heat up 5.4 times faster than Cordierite per the same amount of mass, but Cordierite has the capacity to hold 2.93 times more heat than stainless steel per the same amount of mass. Another ceramic, Alumina (Aluminum oxide), will heat up 11 times faster, but hold 1.94 times less heat. By comparison, Cordierite takes longer to heat up than these materials, but you have to consider that these materials transfer heat so quickly, you could end up burning the bottom of the pizza.

Based on its thermal properties, I don't see why it would take much longer than a normal pizza stone if it's of similar size and weight. If you tell me what temperature you want to bake at, I can tell you about how long it will take to heat up.

- red.november

jefe · « **Reply #7 on:** May 16, 2007, 09:20:16 PM »

Well, I have a no-frills Kenmore Electric oven that I turn up as high as it goes which is 550 F. It is not self-cleaning so that's as high as I think I can get it.

I don't know if using the broiler setting (element on top) would permit the oven to get hotter or not.

(FYI, I am currently using a Pampered Chef Pizza Stone but wanted to have a bigger "target" so I could increase the size of the pizza I am making.)

November · « **Reply #8 on:** May 16, 2007, 10:20:53 PM »

To raise the temperature of a 17" x 17" x 0.75" shelf made of Cordierite, from 68°F to 550°F, it would take approximately 38 minutes 53 seconds.

- red.november

jefe · « **Reply #9 on:** May 17, 2007, 11:06:07 AM »

Do you have any thoughts on how this would function for cooking pizza in a home oven?

November · « **Reply #10 on:** May 17, 2007, 11:49:38 AM »

jefe,

I have never used Cordierite for baking pizzas, but based on knowing its thermal properties, I don't see any reason why it couldn't be used. It is in fact used for that purpose anyway:

http://www.chefscatalog.com/catalog/product.aspx?item=12431&sourcecode=7w4pfd413

- red.november

jefe · « **Reply #11 on:** June 02, 2007, 09:46:55 PM »

Just following up. Got a 15" x 15" x 5/8" kiln shelf from Sheffield Pottery made of Cordierite. I wasn't sure if I needed to do the outgassing thing or not so I did just to be safe. The only other thing that concerned me was there was a number labelled on it with blue ink. I tried sanding it off but it seemed to go deep into the substance of the stone itself. It's only on 1 side so I tried not to cook on that area (but accidentally did anyway).

Anyway, the pizza came out good. The oven took a lot longer to heat up than it used to with only my pampered chef stone. In this case I cooked on the cordierite and put the old stone on the shelf above.

I'm not dead yet. So, I guess so far, so good.

November · « **Reply #12 on:** September 03, 2007, 07:42:58 PM »

Here is some pricing news for Sheffield Pottery's kiln shelves. Right now they are having an "overstock" sale on several of their shelves in sizes convenient for the home oven. I just picked up a 16" x 16" x 0.75" shelf for myself.

http://www.sheffield-pottery.com/SUPER-SALE-OVERSTOCK-Corderite-Kiln-Shelves-s/386.htm

http://www.unclesalmon.com/lib/images/products/cordierite_full.jpg

http://www.unclesalmon.com/lib/images/products/cordierite_corner.jpg

- red.november

November · « **Reply #13 on:** September 11, 2007, 09:55:47 PM »

In preparation for using the cordierite shelf for baking a pizza on tomorrow, I carbonized the bottom by mopping it with sugar-water and heating it in the oven at 600°F for about an hour. This is to darken it for more rapid radiant heat absorption. I will likely sugar-heat treat it a few more times before all is said and done. I will only treat the shelf this way on the bottom, as I want the top to remain as reflective as possible to benefit the rim of the crust not in direct contact with the shelf. Attached is an image of the contrast resulting from the first treatment.

- red.november

November · « **Reply #14 on:** September 17, 2007, 08:27:06 PM »

I just thought I would throw up an image or two of a pizza I baked tonight on the cordierite shelf. I have been baking on this shelf constantly since September 11, but I haven't stopped to take pictures of the products until tonight. Even tonight's picture taking was totally unplanned, so the images aren't really all that great due to a rushed setup. The pizza however was great. It simply had mozzarella cheese and baby portobello mushrooms (no sauce).

- red.november

abatardi · « **Reply #15 on:** September 17, 2007, 09:44:30 PM »

Looks great man. What temp were these baked at?

- aba

November · « **Reply #16 on:** September 17, 2007, 10:19:16 PM »

Thanks. The oven is set for 600°F, and the shelf hovers just above that after 40 minutes of preheating. This pizza was baked in about 3 minutes.

- red.november

EDIT: FYI, I didn't bother taking a picture of the bottom of the crust, so I rotated the pizza so that the part of the rim (cornicione) with the same coloration as the bottom directly faced the camera.

Matthew · « **Reply #17 on:** January 17, 2009, 09:54:33 AM »

Quote from: November on September 17, 2007, 10:19:16 PM

Thanks. The oven is set for 600°F, and the shelf hovers just above that after 40 minutes of preheating. This pizza was baked in about 3 minutes.

- red.november

EDIT: FYI, I didn't bother taking a picture of the bottom of the crust, so I rotated the pizza so that the part of the rim (cornicione) with the same coloration as the bottom directly faced the camera.

RN,

What is the optimal position for the shelf in the oven?
I currently use a fibrament stone but I am looking at purchasing a Cordierite-mullite shelf for my oven from a local pottery supply. It comes in 3/4" & 1" thickness. I am thinking the 1" is much better. Do you have any data to compare the 2 thicknesses?

Thanks,
Matt

November · « **Reply #18 on:** January 17, 2009, 11:06:22 AM »

Quote from: Matthew on January 17, 2009, 09:54:33 AM

What is the optimal position for the shelf in the oven?

It depends on what you're baking and how you want it baked. There are many threads on this forum that talk about stone or shelf placement.

Quote from: Matthew on January 17, 2009, 09:54:33 AM

I currently use a fibrament stone but I am looking at purchasing a Cordierite-mullite shelf for my oven from a local pottery supply.

I would keep the Fibrament stone unless there was something wrong with it.

Quote from: Matthew on January 17, 2009, 09:54:33 AM

It comes in 3/4" & 1" thickness. I am thinking the 1" is much better. Do you have any data to compare the 2 thicknesses?

Yes, the data you just provided. The 1" shelf is about 33% thicker than the 3/4" shelf.

- red.november

Matthew · « **Reply #19 on:** January 17, 2009, 03:10:14 PM »

I would keep the Fibrament stone unless there was something wrong with it.

- red.november

There is nothing wrong with the fibrament stone except the size, it only 13". I just purchased an 18" x 18" Cordierite-mullite kiln shelf, unfortunately they discontinued the 1" thick so I had to buy the 3/4". They also had the SC kiln shelves, the store owner discouraged me from buying it due to its fragile nature.

They also had a great deal on round 16" x 1/2" pure cordierite @$19 each. I'm thinking that 2 of these on top of one another would be great on an LBE.