After preparing and partially boiling vegetables and meat, they were then
put in a large glass bowl and it was placed on top of a gas hob to bring
them to
the boil. That was prior to placing it in the oven to make an oven
casserole.

This practice has been done by me quite a few times before. I've always
assumed that a Pyrex bowl can be placed on a gas ring and the contents
boiled, because someone I know has Pyrex glass saucepans, that they use to
boil things in.

However the wife doesn't think that these glass bowls should undergo this
kind of treatment on top of the gas rings.

Today using a smoky dark coloured glass bowl which I don't think I've used
before,
but I really thought it was an oven proofed bowl. It suddenly completely
collapsed into pieces as I placed it in the oven. What a mess.........

My question is not whether this was really an oven proofed glass dish, since
i guess we will never know for sure.

But is the wife right in saying this is a very *risky* procedure, putting a
pyrex glass bowl over a gas ring to boil things? Even though i always start
on
the minimum heat so as to minimize any strains on the glass. So would
you think that this is safe to do, or not? Thanks.

On Mar 14, 9:14 am, "john south" > wrote:
> After preparing and partially boiling vegetables and meat, they were then
> put in a large glass bowl and it was placed on top of a gas hob to bring
> them to
> the boil. That was prior to placing it in the oven to make an oven
> casserole.
>
> This practice has been done by me quite a few times before. I've always
> assumed that a Pyrex bowl can be placed on a gas ring and the contents
> boiled, because someone I know has Pyrex glass saucepans, that they use to
> boil things in.
>
> However the wife doesn't think that these glass bowls should undergo this
> kind of treatment on top of the gas rings.
>
> Today using a smoky dark coloured glass bowl which I don't think I've used
> before,
> but I really thought it was an oven proofed bowl. It suddenly completely
> collapsed into pieces as I placed it in the oven. What a mess.........
>
> My question is not whether this was really an oven proofed glass dish, since
> i guess we will never know for sure.
>
> But is the wife right in saying this is a very *risky* procedure, putting a
> pyrex glass bowl over a gas ring to boil things? Even though i always start
> on
> the minimum heat so as to minimize any strains on the glass. So would
> you think that this is safe to do, or not? Thanks.

google is your friend

Jim K

john south wrote:
> After preparing and partially boiling vegetables and meat, they were then
> put in a large glass bowl and it was placed on top of a gas hob to bring
> them to
> the boil. That was prior to placing it in the oven to make an oven
> casserole.
>
> This practice has been done by me quite a few times before. I've always
> assumed that a Pyrex bowl can be placed on a gas ring and the contents
> boiled, because someone I know has Pyrex glass saucepans, that they use to
> boil things in.
>
> However the wife doesn't think that these glass bowls should undergo this
> kind of treatment on top of the gas rings.
>
> Today using a smoky dark coloured glass bowl which I don't think I've used
> before,
> but I really thought it was an oven proofed bowl. It suddenly completely
> collapsed into pieces as I placed it in the oven. What a mess.........
>
> My question is not whether this was really an oven proofed glass dish, since
> i guess we will never know for sure.
>
> But is the wife right in saying this is a very *risky* procedure, putting a
> pyrex glass bowl over a gas ring to boil things? Even though i always start
> on
> the minimum heat so as to minimize any strains on the glass. So would
> you think that this is safe to do, or not? Thanks.
>
>
>
IANAE but apart from a specific glass saucepan, I 'wouldn't have dreamt
of putting a Pyrex bowl directly on a gas hob. We regularly use ceramic
ovenproof dishes, but again, I would not have considered putting them
directly on the hob. Just my two-penneth FWIW.

"john south" > wrote in message
...
> After preparing and partially boiling vegetables and meat, they were then
> put in a large glass bowl and it was placed on top of a gas hob to bring
> them to
> the boil. That was prior to placing it in the oven to make an oven
> casserole.
>
> This practice has been done by me quite a few times before. I've always
> assumed that a Pyrex bowl can be placed on a gas ring and the contents
> boiled, because someone I know has Pyrex glass saucepans, that they use to
> boil things in.
>
> However the wife doesn't think that these glass bowls should undergo this
> kind of treatment on top of the gas rings.
>
> Today using a smoky dark coloured glass bowl which I don't think I've used
> before,
> but I really thought it was an oven proofed bowl. It suddenly completely
> collapsed into pieces as I placed it in the oven. What a mess.........
>
> My question is not whether this was really an oven proofed glass dish,
> since
> i guess we will never know for sure.
>
> But is the wife right in saying this is a very *risky* procedure, putting
> a
> pyrex glass bowl over a gas ring to boil things? Even though i always
> start on
> the minimum heat so as to minimize any strains on the glass. So would
> you think that this is safe to do, or not? Thanks.

I'm with your wife on this one!

I know has Pyrex glass saucepans, that they use to
boil things in.

However the wife doesn't think that these glass bowls should undergo this
kind of treatment on top of the gas rings.My question is not whether this was really an oven proofed glass dish, since
i guess we will never know for sure.I 'wouldn't have dreamt
of putting a Pyrex bowl directly on a gas hob. We regularly use ceramic
ovenproof dishes, but again,But is the wife right in saying this is a very *risky* procedure, putting
a
pyrex glass bowl over a gas ring to boil things? Even though i always
start on

In article >,
"john south" > writes:
> After preparing and partially boiling vegetables and meat, they were then
> put in a large glass bowl and it was placed on top of a gas hob to bring
> them to
> the boil. That was prior to placing it in the oven to make an oven
> casserole.
>
> This practice has been done by me quite a few times before. I've always
> assumed that a Pyrex bowl can be placed on a gas ring and the contents
> boiled, because someone I know has Pyrex glass saucepans, that they use to
> boil things in.

Pyrex doesn't imply a particular type of glass. Originally it was
borosilicate glass, but it's now just used as a well-known trade
name to sell various different types of glass. Different companies
use the name differently in different parts of the world.

Borosilicate glass tends to be used for higher temperature applications,
although I don't know what glass saucepans are made of.

Even soda-lime glass (used for most glass applications) shouldn't melt
in an ordinary domestic oven. Sometimes it's toughened - did it break
like a toughened windscreen shattering?

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Gabriel wrote:
> In article >,
> "john south" > writes:
>> After preparing and partially boiling vegetables and meat, they were then
>> put in a large glass bowl and it was placed on top of a gas hob to bring
>> them to
>> the boil. That was prior to placing it in the oven to make an oven
>> casserole.
>>
>> This practice has been done by me quite a few times before. I've always
>> assumed that a Pyrex bowl can be placed on a gas ring and the contents
>> boiled, because someone I know has Pyrex glass saucepans, that they use to
>> boil things in.
>
> Pyrex doesn't imply a particular type of glass. Originally it was
> borosilicate glass, but it's now just used as a well-known trade
> name to sell various different types of glass. Different companies
> use the name differently in different parts of the world.
>
> Borosilicate glass tends to be used for higher temperature applications,
> although I don't know what glass saucepans are made of.
>
> Even soda-lime glass (used for most glass applications) shouldn't melt
> in an ordinary domestic oven. Sometimes it's toughened - did it break
> like a toughened windscreen shattering?
>
The key is the expansion rate. If one part is much hotter than another,
as can happen with gas when the bit with water in stays at 100C but eh
bit above water goes higher, thermal expansion can crack the top off in
a neat ring.


Pyrex is a low thermal coefficient of expansion glass. That's all.

So you can pour boiling water into it and it wont crack.

On Mon, 14 Mar 2011 09:14:27 -0000, "john south"
> wrote:

>But is the wife right in saying this is a very *risky* procedure, putting a
>pyrex glass bowl over a gas ring to boil things? Even though i always start
>on the minimum heat so as to minimize any strains on the glass.

http://www.snopes.com/food/warnings/pyrex.asp

On 14/03/11 09:14, john south wrote:

> Today using a smoky dark coloured glass bowl which I don't think I've used
> before,
> but I really thought it was an oven proofed bowl. It suddenly completely
> collapsed into pieces as I placed it in the oven. What a mess.........
>
> My question is not whether this was really an oven proofed glass dish, since
> i guess we will never know for sure.

Au contraire mon ami. We know about it's oven-proof status. What we
don't know is whether it was designed to be so.

>
> But is the wife right in saying this is a very *risky* procedure, putting a
> pyrex glass bowl over a gas ring to boil things? Even though i always start
> on
> the minimum heat so as to minimize any strains on the glass. So would
> you think that this is safe to do, or not? Thanks.

I wouldn't do it. The type of glass pan that can be put on direct heat
is a comparatively new invention. Pyrex has existed a lot longer than that.


--
Bernard Peek

On 14/03/2011 11:09, Bernard Peek wrote:

>
> ... The type of glass pan that can be put on direct heat
> is a comparatively new invention.

Maybe, but glass test-tubes and conical flasks have been used over
Bunsen burners for a very long time.

--
Reentrant

On Mar 14, 12:03*pm, Reentrant > wrote:
> On 14/03/2011 11:09, Bernard Peek wrote:
>
>
>
> > ... The type of glass pan that can be put on direct heat
> > is a comparatively new invention.
>
> Maybe, but glass test-tubes and conical flasks have been used over
> Bunsen burners for a very long time.

Your point being....?

Reentrant wrote:
> On 14/03/2011 11:09, Bernard Peek wrote:
>
>>
>> ... The type of glass pan that can be put on direct heat
>> is a comparatively new invention.
>
> Maybe, but glass test-tubes and conical flasks have been used over
> Bunsen burners for a very long time.
>
Much thinner walls. less likely to crack.

"Tim Streater" > wrote in message
...
> In article >,
> Reentrant > wrote:
>
>> On 14/03/2011 11:09, Bernard Peek wrote:
>>
>> >
>> > ... The type of glass pan that can be put on direct heat
>> > is a comparatively new invention.
>>
>> Maybe, but glass test-tubes and conical flasks have been used over Bunsen
>> burners for a very long time.
>
> Relatively thin glass though. And I don't think you heat them up empty. Or
> do you? - I heated a mixture of flowers of sulphur and potassium
> permanganate in a test tube once on a little burner at home. Nothing much
> happened for a while, then there was a "thunk" and all the mixture shot
> out as a plug, through the window I'd left open just in case.
>
> --
> Tim


There is a difference between oven proof and flame proof. They are made
and tempered differently.

On 3/14/2011 7:09 AM, Bernard Peek wrote:

> I wouldn't do it. The type of glass pan that can be put on direct heat
> is a comparatively new invention. Pyrex has existed a lot longer than that.
>
>
Back in the 1950s, my mother had a Pyrex saucepan, complete with
detachable handle. It was used on a gas hob nearly every day for
decades. It _was_ sold as a saucepan. Her Pyrex bowls were were not
intended for direct heat cooking.

S Viemeister wrote:
> On 3/14/2011 7:09 AM, Bernard Peek wrote:
>
>> I wouldn't do it. The type of glass pan that can be put on direct
>> heat
>> is a comparatively new invention. Pyrex has existed a lot longer
>> than that.
>>
>>
> Back in the 1950s, my mother had a Pyrex saucepan, complete with
> detachable handle. It was used on a gas hob nearly every day for
> decades. It _was_ sold as a saucepan. Her Pyrex bowls were were not
> intended for direct heat cooking.

Exactly. It might even have a symbol or warning on the bottom of
that bowl that it's not to be used over an open flame.

nancy

"john south" > wrote in message
...

> But is the wife right in saying this is a very *risky* procedure, putting
> a
> pyrex glass bowl over a gas ring to boil things? Even though i always
> start on
> the minimum heat so as to minimize any strains on the glass.

Even minimum heat involves a naked gas flame so would be very hot (try
holding your finger over it!). And being more localised might result in even
more stresses.

Trying using a microwave oven instead. Or a different vessel.

--
Bartc

On Mar 14, 9:14*am, "john south" > wrote:
> After preparing and partially boiling vegetables and meat, they were then
> put in a large glass bowl and it was placed on top of a gas hob to bring
> them to
> the boil. That was prior to placing it in the oven to make an oven
> casserole.
>
> This practice has been done by me quite a few times before. *I've always
> assumed that a Pyrex bowl can be placed on a gas ring and the contents
> boiled, because someone I know has Pyrex glass saucepans, that they use to
> boil things in.
>
> However the wife doesn't think that these glass bowls should undergo this
> kind of treatment on top of the gas rings.
>
> Today using a smoky dark coloured glass bowl which I don't think I've used
> before,
> but I really thought it was an oven proofed bowl. It suddenly completely
> collapsed into pieces as I placed it in the oven. What a mess.........

What a prat....

On Mar 14, 9:14*am, "john south" > wrote:
> After preparing and partially boiling vegetables and meat, they were then
> put in a large glass bowl and it was placed on top of a gas hob to bring
> them to
> the boil. That was prior to placing it in the oven to make an oven
> casserole.
>
> This practice has been done by me quite a few times before. *I've always
> assumed that a Pyrex bowl can be placed on a gas ring and the contents
> boiled, because someone I know has Pyrex glass saucepans, that they use to
> boil things in.
>
> However the wife doesn't think that these glass bowls should undergo this
> kind of treatment on top of the gas rings.
>
> Today using a smoky dark coloured glass bowl which I don't think I've used
> before,
> but I really thought it was an oven proofed bowl. It suddenly completely
> collapsed into pieces as I placed it in the oven. What a mess.........
>
> My question is not whether this was really an oven proofed glass dish, since
> i guess we will never know for sure.
>
> But is the wife right in saying this is a very *risky* procedure, putting a
> pyrex glass bowl over a gas ring to boil things? *Even though i always start
> on
> the minimum heat so as to minimize any strains on the glass. * * So would
> you think that this is safe to do, or not? * *Thanks.

Sorry to go off topic, and not wanting to hijack the thread, but why
did you do it? Was it to try to cut down on the time it would be in
the oven?

On 14/03/2011 09:14, john south wrote:
>
> the minimum heat so as to minimize any strains on the glass. So would
> you think that this is safe to do, or not? Thanks.
>

You should get an induction hob. They are idiot proof in that respect!

As students we learnt that pinching half pint jugs from the bar to make
coffee in was a waste of time. Though I recall someone having one that
did last for some time.


--
Michael Chare

On Mar 14, 1:20 pm, Michael Chare >
wrote:
> On 14/03/2011 09:14, john south wrote:
>
>
>
> > the minimum heat so as to minimize any strains on the glass. So would
> > you think that this is safe to do, or not? Thanks.
>
> You should get an induction hob. They are idiot proof in that respect!

and some steel/iron casseroles & pans...

Jim K

In article >, star09558
@mail.invalid says...

> But is the wife right in saying this is a very *risky* procedure,
putting a
> pyrex glass bowl over a gas ring to boil things?

Yes.

RTFM

http://www.pyrexware.com/index.asp?pageId=28

Janet

john south > wrote:

>But is the wife right in saying this is a very *risky* procedure, putting a
>pyrex glass bowl over a gas ring to boil things?

Absolutely. Never put thick glass on a flame. Did you ever take
chem lab? The beakers and such that you place over a bunsen burner
are all thin glass.

Steve

Steve Pope wrote:
> john south > wrote:
>
>> But is the wife right in saying this is a very *risky* procedure,
>> putting a pyrex glass bowl over a gas ring to boil things?
>
> Absolutely. Never put thick glass on a flame.

Um...
http://www.amazon.co.uk/Visions-2-5L...0115322&sr=8-3


> Did you ever take
> chem lab? The beakers and such that you place over a bunsen burner
> are all thin glass.

I think the type of glass has more to do with it. Clearly though, pyrex
*bowls* are not designed to be put directly on a flame.

Tim

On Mar 14, 2:14*am, "john south" > wrote:
> After preparing and partially boiling vegetables and meat, they were then
> put in a large glass bowl and it was placed on top of a gas hob to bring
> them to
> the boil. That was prior to placing it in the oven to make an oven
> casserole.

> My question is not whether this was really an oven proofed glass dish, since
> i guess we will never know for sure.
>
> But is the wife right in saying this is a very *risky* procedure, putting a
> pyrex glass bowl over a gas ring to boil things? *Even though i always start
> on
> the minimum heat so as to minimize any strains on the glass. * * So would
> you think that this is safe to do, or not? * *Thanks.

The heat stress from applying a flame to a glass bowl is much higher
because the high temperature is much higher: 3500F for a methane
flame vs 500 at most for the oven.

Pyrex made a "Visions" line of glass saucepans -- try to find one of
those.

On Mon, 14 Mar 2011 09:14:27 -0000, "john south"
> wrote:

> But is the wife right in saying this is a very *risky* procedure, putting a
> pyrex glass bowl over a gas ring to boil things? Even though i always start
> on the minimum heat so as to minimize any strains on the glass. So would
> you think that this is safe to do, or not? Thanks.
>
I have a Pyrex double boiler, that is fine with that kind of heat -
but unless you're using laboratory grade material, risky is putting it
nicely. You do love living dangerously! I hope you're prepared for
some kitchen cleanup and a possible trip to the hospital if you
continue your half-witted practice of exposing home grade Pyrex bowls
to a flame.

--

Today's mighty oak is just yesterday's nut that held its ground.

In article >,
says...
> I have a Pyrex double boiler, that is fine with that kind of heat -
> but unless you're using laboratory grade material, risky is putting it
> nicely. You do love living dangerously! I hope you're prepared for
> some kitchen cleanup and a possible trip to the hospital if you
> continue your half-witted practice of exposing home grade Pyrex bowls
> to a flame.
>

And if it's "new" Pyrex, don't bother anyway.

--
Skipweasel - never knowingly understood.