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Jackson
Known Hero
Random Spirit Lover
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posted December 15, 2011 08:03 AM |
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Glass Bakeware!
Borosilicate vs. soda lime glass. I really wish there was more information.
http://www.consumerreports.org/cro/magazine-archive/2011/january/home-garden/glass-cookware/glass-cookware/index.htm
Discuss, please.
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Tsar-Ivor
Promising
Legendary Hero
Scourge of God
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posted December 15, 2011 09:26 AM |
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Thanks, now I know what I'm getting my brother for christmas.
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"No laughs were had. There is only shame and sadness." Jenny
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Corribus
Hero of Order
The Abyss Staring Back at You
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posted December 15, 2011 04:19 PM |
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Edited by Corribus at 16:41, 15 Dec 2011.
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Borosilicate glass has lower coefficient for thermal expansion (almost 3x lower). Which means, it is less susceptible to sudden changes in temperature. This is primarily because it is a harder material by virtue of the fact that it contains stable boron-oxygen chemical bonds. When solids change temperature, they also change volume. Materials with low coefficients for thermal expansion (Pyrex) change their volumes only a little - materials with high coefficients do the opposite. The amount of stress a material is exposed to is related to the rate at which the material changes volume. When a material like soda lime changes temperature suddenly, the volume change is also sudden, and any defects in the glass will cause catastrophic material failure due to the high stress forces applied.
Practically, this means that ordinary glass (soda lime) will shatter if it's really hot and is cooled very quickly - such as exposing it to a cold counter top, cold water, or even cold air from opening an oven door. I have had this happen to me once when I was using a baking dish I thought was Pyrex and in fact was just cheap soda lime. My wife was baking a chicken in the oven and had set it over the glass dish. The drippings collecting in the glass dish started to burn so she wanted to add some water. Thing literally exploded - sounded like a shotgun blast - and glass went everywhere.
I said to her, "Well, there's a hard lesson in thermal expansion coefficients."
I've also had some glass containers shatter when pouring (stupidly, because I'm a chemist and should know better) boiling water into them to brew tea. Always brew your tea in metal or plastic containers. 
Your solutions:
Use a high quality borosilicate glass (Pyrex) which is much less susceptible (but not impervious) to thermal expansion.
Never heat a glass baking vessel in the oven if it doesn't have anything in it. Since water (and food) has a high specific heat, it can absorb a lot of the energy that would otherwise go into changing the temperature of the glass when you remove it from the oven.
If you need a vessel to just collect drippings, use metal. Though metal actually has a higher thermal expansion coefficient than glass (much higher, in fact), metal is a much stronger (less brittle) material and can therefore tolerate rapid volume changes without posing a thread to your health.
EDIT: You can read more about it here.
EDIT2: As for the posted link: people don't understand how much stress sudden temperature changes put on a material. Pyrex is not INVINCIBLE. It's just more resistant than regular glass. Even Pyrex should not be exposed to huge and sudden temperature changes - 350 degree oven to a 65 degree countertop - that's a huge temperature gradient. Also, all that stress adds up over time - after many uses, the material can get fatigued, which means a Pyrex dish that wouldn't fail when new could easily fail when it's 5 years old. In general, unless I'm baking a casserole or a pie, I never put glass in the oven.
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I'm sick of following my dreams. I'm just going to ask them where they're goin', and hook up with them later. -Mitch Hedberg
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Jackson
Known Hero
Random Spirit Lover
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posted December 16, 2011 02:40 AM |
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Hey, thanks for the insightful post, Corribus!
The conclusion I'm drawing is that if I simply use my glassware with care and within the safety limits, that I should have little to worry about.
Still, it's such a bummer to learn that even glassware carries with it dangers greater than simply dropping them... But for me, the draw to glass is that it doesn't leech chemicals into your food, unlike, well, everything else...
Even stainless steel, which many people regard as the safest material to cook in, leeches nickel into your food.
Iron, another favorite, leaches (obviously) iron...
And it just gets worse from there with things like aluminium and Teflon...
Hey, maybe a raw food diet IS the best way to go. 
By the way, Corribus, American Pyrex is unfortunately not made of borosilicate. Well, their chem gear is, but not their bakeware. European Pyrex bakeware, on the other hand, is still made of borosilicate, and I'm thinking about importing. 
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blizzardboy
Honorable
Undefeatable Hero
Nerf Herder
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posted December 16, 2011 05:41 PM |
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Well, if you've got a thing for glass, the whole explosion thing can be avoided well enough if you don't take it out of the oven immediately. A lot of baking recipes will tell you to let it sit in the oven for several minutes anyway. I don't bake with glass, but when I'm baking a cake or something after I turn off the oven I'll crack it open, just so some of the heat filters out and it doesn't continue to cook significantly, or you just remember to turn off the oven a few minutes prior to when it should be done.
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"Folks, I don't trust children. They're here to replace us."
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Corribus
Hero of Order
The Abyss Staring Back at You
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posted December 16, 2011 06:31 PM |
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Edited by Corribus at 18:33, 16 Dec 2011.
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@Jackson
Quote:
The conclusion I'm drawing is that if I simply use my glassware with care and within the safety limits, that I should have little to worry about.
You have little to worry about as long as you don't bake with or otherwise heat empty glassware.
Quote:
Still, it's such a bummer to learn that even glassware carries with it dangers greater than simply dropping them... But for me, the draw to glass is that it doesn't leech chemicals into your food, unlike, well, everything else...
I use glass "tupperwares" because they last longer and don't scalp colors and flavors like plastic containers do. I don't worry too much about leeching from plastics, at least in commercial processed foods, because (in the US at least), any commercial food packaging material has to be demonstrated safe by an enormous amount of acquried data in order to be approved for use by FDA. I certainly wouldn't store or heat foods in plastics that aren't intended for foods. Otherwise, I don't worry about it.
As for this:
Quote:
Even stainless steel, which many people regard as the safest material to cook in, leeches nickel into your food.
Iron, another favorite, leaches (obviously) iron...
And it just gets worse from there with things like aluminium and Teflon...
For any type of metal cookware (pots and pans) the important thing is to keep the cookware in good condition. Don't use really abrasive cleaners and if there are large gouges or scratches, it's probably time to replace. Aluminum (unless its anodized) is usually used in cheaper pots and pans, and aside from not performing nearly as well as steel or copper as far as heat distribution goes, aluminum is also far more reactive. Anodized aluminum is much better. I wouldn't worry about steel or iron at all. These metals aren't toxic in small amounts and are far less reactive than aluminum.
Teflon is somewhat different. Being a plastic, it is prone to decomposition, but only at high temperatures (generally over 500 F). I use Teflon all the times and my rule of thumb is this: don't heat a Teflon pan with nothing in it, and don't use a Teflon pan if you've brought an oil to its smoke point. Since the smoke point of most oils is below 500 F, as long as the oil isn't smoking, the Teflon coating isn't hot enough to decompose. Obviously, never stick a Teflon pot (hell, any pot) under a broiler. Also, if you notice any scratches or gouges in the surface of a Teflon pot or pan, it's time to throw away.
Quote:
Hey, maybe a raw food diet IS the best way to go.
Well, then you have to worry about pesticides.
Quote:
By the way, Corribus, American Pyrex is unfortunately not made of borosilicate. Well, their chem gear is, but not their bakeware. European Pyrex bakeware, on the other hand, is still made of borosilicate, and I'm thinking about importing.
American Pyrex bakeware is made of tempered soda-lime glass. What's important in materials properties isn't only the chemical composition but also the way the material is forged. Which is to say, not all soda lime glasses are created equal, just like all polyethylene plastics are not equal. A lot depends on the conditions at which it is melted and cooled - crytallinity, density, etc. are all affected by these processes.
You might find this link helpful:
http://www.pyrexware.com/index.asp?pageId=30
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I'm sick of following my dreams. I'm just going to ask them where they're goin', and hook up with them later. -Mitch Hedberg
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OmegaDestroyer
Hero of Order
Fox or Chicken?
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posted December 16, 2011 08:30 PM |
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What kind of men sit around and waste their time discussing things like bakeware!?
Pff... not real men. No sir. You people make me sick.
On a completely unrelated note, my 12-inch anodized aluminum springform baking pan came in today! Homemade cinnamon rolls for Christmas morning ftw!
____________
The giant has awakened
You drink my blood and drown
Wrath and raving I will not stop
You'll never take me down
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Corribus
Hero of Order
The Abyss Staring Back at You
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posted December 16, 2011 08:50 PM |
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I never claimed to be a real man.
Currently my favorite cookware is enamel-coated iron. Expensive as hell but it has the heat carrying capacity of cast iron with the easy of use of Teflon. You can heat it on a stove or bake with it in the oven. Easily the best thing I've ever purchased for making food.
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OmegaDestroyer
Hero of Order
Fox or Chicken?
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posted December 16, 2011 09:55 PM |
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I would love to get my hands on a nice copper pan. Unfortunately, I don't have the kind of money need to purchase copper cookware. 
____________
The giant has awakened
You drink my blood and drown
Wrath and raving I will not stop
You'll never take me down
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MacMasterMC
Known Hero
Resurrected Loreweaver
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posted March 19, 2012 11:19 AM |
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DOUBLE RESURRECTION!
Ahem, why would you want copper cookware?
And in regards to your concern with iron cookware, leeching iron into your food, like cast iron actually does, is not harmful really in any way, and for most people out there, is a positive thing. A lot of people have an iron deficiency that they do not even know about/are aware of, and generally we can all use a little more iron in our diets.
I appreciate the concern with what you leech into foods, though, as some kinds of materials are rather nasty. Like has been said regarding teflon, if damaged get rid of-well, teflon is quite toxic, so I am hesitant to want to use it whether or not its new, since it really is rather a simple thing to scratch almost any kind of cooking material.
At least with iron, our bodies need it anyway and most of us don't get enough, so the leeching is actually desirable. It is why I hope to eventually get a fair number of cast iron cookware pieces, as it also adds a positive flavor to a rather large number of foods. Have you ever had cornbread made in a cast iron skillet? It tastes very good!
____________
...a shimmer in the woods, with
an expectant feel to the air...
...a figure takes shape...
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Corribus
Hero of Order
The Abyss Staring Back at You
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posted March 19, 2012 02:21 PM |
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Copper has excellent heat conduction, and looks rather flashy. I think pots made completely of copper are overrated. A quality stainless pot with a good copper lining on the bottom is sufficient.
Regarding Teflon: Teflon is inert and nontoxic. Decomposition products may not be (which is why you don't heat it too hot). Also some of the additives used to manufacture it are known to be carcinogenic. However EPA has declared no connection (that they have found) between routine use of teflon coated pots and any cause for concern.
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I'm sick of following my dreams. I'm just going to ask them where they're goin', and hook up with them later. -Mitch Hedberg
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MacMasterMC
Known Hero
Resurrected Loreweaver
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posted March 19, 2012 03:40 PM |
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Quote:
However EPA has declared no connection (that they have found) between routine use of teflon coated pots and any cause for concern.
And we know just how accurate and thorough the US government is when it comes to public safety *gets handed something from offscreen* oh wait! They DON'T! LOL
____________
...a shimmer in the woods, with
an expectant feel to the air...
...a figure takes shape...
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Ghost
Undefeatable Hero
Therefore I am
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posted March 26, 2012 12:28 AM |
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I do not have glasses, I use cast iron and clay. Each day with a good food, if you want, thanks
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Fight MWMs - stand teach
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