Original research
Pyrex sold in Australia is two different glasses under one name, and they fail in different ways. The distributor publishes the rule that tells them apart — ten years means French borosilicate, two years means American soda-lime. Almost nobody knows to look.
If you own Pyrex, you own one of two completely different materials. They look identical, they carry the same brand, they sit on the same shelf — and they break in different ways.
There is a way to tell them apart, and it is not on the box. It is the warranty.
Pyrex, Corelle, CorningWare, Snapware and Visions are distributed in Australia by Global Kitchen Brands. Their Pyrex support page states it plainly:
And their own comparison of the two, which is fair and worth quoting in full: “Soda lime is slightly more resistant to impact breakage than borosilicate, and borosilicate is more resistant to extreme thermal changes than soda lime.”
Neither is better. They fail differently. Soda-lime survives being knocked; borosilicate survives being moved from the freezer to a hot oven.
Pyrex was originally borosilicate everywhere. The American licence moved to tempered soda-lime decades ago while the European licence stayed borosilicate, and the brand is now owned by different companies in different markets. Australia imports from both. So the word Pyrex tells you who made it, not what it is.
Two products, one brand, one distributor, one website.
The Cook & Freeze 4L storage dish says “Made from high quality borosilicate glass”, states “Made in France”, and publishes a full thermal specification: −40°C to +300°C, with thermal shock resistance to 220°C. Ten-year warranty on the glass. That is a complete, checkable answer and it scores 68 on our materials rubric.
The Originals 4.5L oblong baking dish says “Durable high-quality tempered glass” and “Made in USA”. It never uses the word soda-lime. You have to take “Made in USA”, carry it to the support page, and apply the rule yourself.
Its care instructions are the tell, if you know to look: “Avoid extreme temperature changes” and “Always preheat oven before inserting glassware”. Those are exactly the instructions soda-lime needs. The page gives you the precaution and withholds the reason.
Worth knowing separately: that dish is explicitly not for stovetop, grill, toaster oven or air fryer. Given how many Australian kitchens have gained an air fryer in the last three years, that is a restriction a lot of people are unknowingly breaking.
Pyrex’s “Zero Plastic” range is the one product in our entire table where the food-contact surface and the lid are the same declared material: “The base and the lid are made from borosilicate Pyrex glass, all made in France.”
Nothing to leach, nothing to degrade, nothing to swap out when a chemical falls from favour. It scores 77, the highest of any food storage container we have scored in Australia. Our one complaint is the name: it is called Zero Plastic and the seal is not disclosed, and a glass-on-glass lid still needs a gasket.
Pyrex is unusual only in that the answer exists somewhere. Across the 57 glass products we have scored, just 16 — 28% — name the glass chemistry at all. The rest say “tempered”, or “heat resistant”, or simply “glass”.
Three that are worth naming, because the gap between the claim and the disclosure is wide:
The pattern is consistent and slightly absurd: makers will specify the plastic and hand-wave the glass, when the glass is the part being put in the oven.
Credit where it is earned. Seed & Sprout publishes “semi-tempered soda lime glass” — naming the chemistry and the treatment level, which nobody else does. And Kmart names borosilicate on a $9 lunchbox, while its own $20 oven-rated glass storage set does not name the glass at all. The template can do it. It is a per-product decision.
Check the warranty before you buy Pyrex. Ten years is French borosilicate. Two years is American soda-lime or Chinese borosilicate. It is printed on the packaging and it is the only reliable signal.
If you go freezer-to-oven, you want borosilicate. That is the whole reason the distinction exists. If your dish mostly gets knocked about in a cupboard, soda-lime is genuinely the tougher choice.
Preheat the oven, always. Sliding cold glass into a heating oven is the failure mode both materials share, and it is what every manufacturer’s care instruction is quietly warning you about.
Do not put glass storage in an air fryer unless it says so. Air fryers heat fast and unevenly, which is precisely the condition glass dislikes. Pyrex Originals names the air fryer as an exclusion; most brands have not updated their guidance at all.
Every glass product we have scored, with what each maker does and does not say, is on our food storage page and the Australian edition. The rubric is here.
New scores, brands that finally answered, and any rule change that affects what you can buy. The list is not open yet — email us and we will add you when it is.