Dishes marketed under the Pyrex name are no longer borosilicates. The brand name was sold off (and in fact the company that bought it was recently discussed in HN as they also bought Instant Pot, and have gone bankrupt).
When you hold it in the hand, real borosilicate glassware is very easy to distinguish from other glassware, because it is noticeably less heavy.
Borosilicate is more durable than regular glass. It's generally less prone to shattering, and it's also more tolerant of rapid temperature changes.
As far as microplastics go, I don't think it's any better than regular glass, but its properties do make it more suitable for the things we may want to replace plastic for.
In general. But less durable from physical shock (not temperature shock) than tempered soda lime glass which is what new pyrex is.
New pyrex Is Not Boro.
Pipe makers used to show off their boro pipes by Throwing them at the ground.... Something you could never dream of doing with traditional glass (soda lime).
Why do you folks keep saying this?
At least google it first.
Yes.
> New pyrex Is Not Boro.
I never made the claim that it was. I was very clear and said tempered soda lime glass is more resistant to physical shock than regular borosilicate glass. I am not comparing borosilicate glass to regular soda lime glass. I've cracked a Chemex before dropping it too hard on a counter. I had a tempered glass coffee table when I was a kid and that survived kids standing on it, plates dropped on it, you name it.
> Why do you folks keep saying this?
Personal experience and articles like this: https://www.nytimes.com/wirecutter/blog/tempered-vs-borosili...
> At least google it first.
At least learn to properly read what I wrote.
You sure about that? I always heard that borosilicate was significantly less durable (30% is the figure I remember, not sure if that's 30% less or 70% less) and all the thermal shock resistance came from lowering the CTE.
I don't know if that was a half truth from a soda-lime salesman or if nostalgia googles are giving borosilicate credit it does not deserve.
That pipe lasted 20+ years until I lost it, meanwhile I broke at least 10 pipes of thicker normal glass. I dropped it in the sink and on the floor countless numbers of times when I braced myself for the sad cleanup, but it always survived.
About half of the glassware that I have been using has been from borosilicate glass and the other half from tempered soda-lime glass. I would have used only borosilicate glass, but it is more difficult to find every size and shape that one may want in borosilicate glass.
Even if not frequently, glassware has been dropped from time to time on floors or in kitchen sinks. Such shocks would have shattered traditional glass, but in most cases both borosilicate glass and tempered soda-lime glass survive.
From an approximately equal number of shocks during the years, I have broken a single borosilicate glass object, a double-walled drinking glass with extremely thin walls, while I have broken somewhere between six and ten tempered glass objects.
The only reason why someone may say that for a certain type of glassware borosilicate glass may be less durable is because it is frequent to make borosilicate glassware with thinner walls, because of its better toughness, while the objects made of tempered glass are invariably made with thick walls, to reduce the risk of breakage.
At equal wall thickness, there is no way for a tempered glass object to be more durable than a borosilicate object.
Moreover I have never seen a borosilicate glass object damaged by thermal shock, but I have broken a tempered glass teapot when attempting to cool it after boiling water in it.
Boro got heavy use in scientific glassware for more than one reason (durability, neutrality, etc)
Soda-Lime glass is the standard glass your think of and it's weak af.
Pipe makers would show off their Boro pipes by throwing them at the ground and having them bounce and stay intact.... Theres a reason that was the way to show off the product compared to traditional glass pipes...
The downside of borosilicate that no one seems to mention is that it is a good bit more fragile when it comes to mechanical shocks. So, if you accidentally hit it with something while it's in the sink, there is a much higher chance that it shatters there.
They're still glass (tempered soda–lime glass), which is what the OP was talking about, so you're just being needlessly pedantic without adding anything to the discussion.
Also, Pyrex is still borosilicate in Europe, since soda-lime is hard to get there.
In that case, I'm not sure whether the borosilicate is obviously the better choice. My biggest concerns is not having the container break in my lunchbox rather than the thermal shock. Which is generally more durable to physical shocks, borosilicate or tempered soda-lime? And then, for the given durability, which is more cost effective?
The chances of being not damaged by a shock depend both on the material and on the wall thickness.
Because they are intrinsically less resistant, the tempered glass objects are typically made with thicker walls.
The end result is that the borosilicate glass objects with thin walls have about the same mechanical shock resistance like the tempered glass objects with thick walls.
Nevertheless, because the soda-lime glass has greater density than borosilicate glass, combined with the fact that the tempered glass objects have thicker walls, makes the tempered glass objects much heavier.
Their great weight makes the tempered glass objects more prone to being dropped during handling.
The borosilicate glassware is more expensive, but the difference is not significant, especially for objects that may remain usable for an entire human lifetime, if used carefully. I have never hesitated to buy some borosilicate glassware because it was too expensive. The main problem has always been that there are few suppliers so it may be difficult to find the exact size and shape that you search.
How is soda-lime glass “hard to get”? The main reason why it's still borosilicate here is because the brand has been licensed to a different company, and their management hasn't chose to stop selling borosilicate.
I'm just going by what Wikipedia says:
"Since the closure of the soda–lime plant in England in 2007, European Pyrex has been made solely from borosilicate."
Something like 30 million plus of glass was made in the EU27 in 2007 in over 200 facilities, nearly all of it would be soda lime glass (i.e. "normal glass"). https://climate.ec.europa.eu/system/files/2016-11/bm_study-g...
In Europe, Pyrex still uses borosilicate glass because it's better and because Europeans are more discerning consumers than Americans. That's my theory anyway. American pyrex cheaped out by switching to soda lime glass.
Wikipedia disagrees with you:
"Since the closure of the soda–lime plant in England in 2007, European Pyrex has been made solely from borosilicate."
Europe makes huge quantities of soda lime glass for a myriad of other applications, soda lime glass simply isn't hard to get in Europe. Wine bottles to windows, all that stuff is soda lime glass; borosilicate glass is a specialized glass that isn't used for most things besides cookware, labware, and sometimes lenses.
We do have glass in some of the windows, you know.
I wouldn't want to trust my casserole in the oven to soda lime glass though. Best to have real pyrex aka borosilicate glass for that.
For the past 15 years there has been a trend of private equity buying brands and destroying them.
Why does this keep making them money? What is this "failure capitalism"?