Craig Martell on tue 13 jan 04
>I thought you had to glaze earthenware with a food safe glaze in order to
>eat or
>cook from it...am I missing something here?
Hi:
The terra cotta pieces I was talking about are just flat, round, clay slabs
that are used for baking and serving pizza. They only come in contact with
the underside of the crust and the clay isn't toxic. Nothing to be
concerned about with food safety.
regards, Craig Martell Hopewell, Oregon
Valerie Mann on tue 13 jan 04
I thought you had to glaze earthenware with a food safe glaze in order to
eat or
cook from it...am I missing something here?..I'm a novice with this so I
appreciate
this list very much
Hugs from snowy London town
Hello Ingeborg:
I guess the short answer here is that large platters are not real durable
for ovenware. I knew a guy who had a business making terra cotta Pizza
Bricks for baking pizzas and he did very well with them. No glaze, heavily
grogged, non vitrified earthenware that could take a lot of stress and had
a very low COE. Large, flat, vitrified ware doesn't adjust that well to
temp changes.
I think that platters would stand a better chance in the oven if some
mechanical factors were looked at carefully. Cross section of the piece
would be important in the respect of gain and loss of applied heat from the
oven. If the rims are too thin there will be faster heat gain and loss
there which could lead to quick failure. If the claybody isn't balanced
well and has formed enough cristobalite there will be loss from expansion
cracking problems. So, there should be enough spar in the body to
eliminate this. Glaze fit is also important. A crazed glaze will weaken
the piece from glaze cracks extending into the interface. A glaze that is
under slight compression, with no crazing, will make a much stronger piece.
If a potter is going to consider recommending platters for ovenware, an
"all of the above" approach would better the chances of survival over a
long period of use. I think that I would tell people to use the large
platters as a serving piece and heat food with other stuff that will
withstand the oven "in and out" ordeal. Cookie sheets work great for
apertifs etc and they are inexpensive and won't crack.
regards, Craig Martell Hopewell, Oregon
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Snail Scott on wed 14 jan 04
At 10:36 AM 1/13/04 -0800, you wrote:
>I thought you had to glaze earthenware with a food safe glaze in order to
>eat or
>cook from it...
You can eat or cook on almost anything; it's getting
it clean afterward that's the 'sticky' part with
earthenware!
Unglazed earthenware is widely used for cooking and
serving, but it will absorb what it holds. Whether
this is a problem or not is up to the user. It's less
sanitary and possibly unhealthy if used for meats,
but not a problem if used for many kinds of beverages,
or to hold foods that won't leave an icky residue.
Vegetable steamers, wine jugs, and 'romertopf' cookers
are common types of functional unglazed earthenware,
as well as the pizza-cooking 'stones' that started
this discussion.
-Snail
Valerie Mann on thu 15 jan 04
Well thanks for the responses...this is very interesting...when I took
ceramic
classes it was drilled in to us..fire at 03 for food safe and then use food
safe
glazes...glaze must always be used for foods...I would love to make a
pizza/bread stone.
Isn't that what they sell at those "Happy chef" parties or whatever they are
called?
I will browze through the clayart archives to see if there are tips on
making a
stone...'
Hugs from London town where we have a "ton" of snow...and soooo cold
At 10:36 AM 1/13/04 -0800, you wrote:
>I thought you had to glaze earthenware with a food safe glaze in order to
>eat or
>cook from it...
You can eat or cook on almost anything; it's getting
it clean afterward that's the 'sticky' part with
earthenware!
Unglazed earthenware is widely used for cooking and
serving, but it will absorb what it holds. Whether
this is a problem or not is up to the user. It's less
sanitary and possibly unhealthy if used for meats,
but not a problem if used for many kinds of beverages,
or to hold foods that won't leave an icky residue.
Vegetable steamers, wine jugs, and 'romertopf' cookers
are common types of functional unglazed earthenware,
as well as the pizza-cooking 'stones' that started
this discussion.
-Snail
.
Andrew Sugden on thu 15 jan 04
It's not any inherent toxicity of the clay that's a concern rather the
open pore structure of porous bodies permitting entry of bacteria. These
will multipy - feeding on the food placed on - and can then contaminate
the next meal.
Whilst some people have suggested that the modern world is becoming too
sterile, and a little bit of dirty is of benefit by strengthening our
immune system, surely we all would want to eat clean and uncontaminated
food. Any ware that comes in contact with food should be impermeable; be
it from a vitreous body or a glazed surface.
From a cold & wet Cornwall,
Andrew
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