Modern US-made Pyrex is made of soda-lime glass, which is vulnerable to "thermal shock" (shattering from sudden temperature changes). To get glassware that is truly superior in heat resistance, look for borosilicate glass or lithium quartz.
Best Borosilicate Glass Pyrex Alternatives
Neither is strictly "better," as they excel at different things. Borosilicate glass is superior if you need high resistance to extreme temperature changes (thermal shock). Tempered Pyrex is better if you want a dish that resists physical impacts, like accidentally dropping it in the sink.
Soda-lime glass is a practical nontoxic option too. Just beware that soda-lime glass may break more easily but is also less expensive. Again, beware that decorative glass—glass with glazes or enamel, is colored, and lead crystal (or crystal)—may leach toxic chemicals or heavy metals.
Pyrex manufacturer Corning transitioned away from borosilicate glass in the United States starting in the 1950s—and officially finalized the shift across all consumer lines when the brand was sold in 1998—for three main reasons:
Yes, borosilicate glass is completely non-toxic. Because it is chemically inert and non-porous, it does not leach harmful chemicals (like BPA, lead, or phthalates) into your food or drinks, even when exposed to extreme heat or acidity.
CorningWare was discontinued in its original form because its manufacturing process—which used a nearly indestructible, heat-shock-resistant ceramic called Pyroceram—became too expensive to produce. Because the cookware was famous for never wearing out, sales eventually slumped, prompting the brand’s owners to pivot to cheaper stoneware.
No, the glass body of Pyrex does not contain or leach microplastics. However, the standard storage lids are made of plastic, meaning they can degrade and release microparticles over time.
No, it is not safe or recommended to use 40-year-old Tupperware (from the 1980s) to store food. Older plastics degrade over time, posing significant health risks.
Ans - Borosilicate glass is more resistant to destruction compared to conventional soda-lime glass, notably regarding thermal stress and impact. However, it is not fully unbreakable and can still break if subjected to excessive force or quick temperature shifts.
Pyrex can last a long time. If you have Pyrex that's still in good condition (i.e., no cracks or chips in the glass), don't throw it away. Give it away or donate it to a thrift shop.
You can tell if glass is borosilicate by looking at its color, performing an oil refraction test, or checking the brand. Borosilicate is highly resistant to thermal shock, meaning it won't shatter when subjected to sudden temperature changes.
Yes, you can safely boil water in borosilicate glass because it can withstand extreme temperature changes without cracking, making it ideal for pouring boiling water directly into a borosilicate glass container or bottle.
When looking for the "healthiest" glass storage containers, the gold standard is high borosilicate glass paired with BPA-free plastic, silicone, or stainless steel lids. Borosilicate glass is highly resistant to thermal shock, won't leach chemicals like lead or phthalates, and doesn't absorb food odors or stains.
NO - Do not use Pyrex® glassware on the stovetop (open flame, electric burner), under the broiler, in a toaster oven, or on a barbecue grill.
Below, Jolene shares eight of the most valuable Pyrex pieces you can own, as well as what makes each so sought after:
Starting around the 1950s, Corning began making Pyrex out of thermally tempered soda–lime glass, instead of borosilicate glass, due to lower manufacturing costs.
Just as before, this feature makes borosilicate glass the ideal material for making sustainable glass bottles. These bottles are long-lasting and don't contain any BPA which could damage your health. Fourth, borosilicate glass is resistant to acid, while soda-lime glass is much less so.
Neither is strictly "better," as they excel at different things. Borosilicate glass is superior if you need high resistance to extreme temperature changes (thermal shock). Tempered Pyrex is better if you want a dish that resists physical impacts, like accidentally dropping it in the sink.
The healthiest containers for storing food are glass, stainless steel, and ceramic. These materials are inert, meaning they won't leach harmful chemicals like BPA, phthalates, or PFAS into your meals—even when exposed to heat.
Anything That's Wet or Damp. You probably know where we're going with this one. "Anything wet or damp is not great to store in a plastic bin with a lid, as this will trap moisture and create mold," Hord says. Let damp or wet items dry out before storing them, or opt for a breathable storage bin material.
You do not need to throw away all of your plastic containers. However, you should discard any that are heavily scratched, warped, stained, or smell. Old plastics (pre-2010) may contain harmful chemicals like BPA, and heated plastic can leach microplastics and chemicals into food.
Modern Pyrex isn’t as durable because the manufacturer switched the material from highly heat-resistant borosilicate glass to soda-lime glass. This change makes the bakeware much more susceptible to shattering from "thermal shock" (e.g., placing a hot dish on a cold counter).
Mice and rats are determined scavengers and will easily eat through most food storage containers such as paper, cardboard and plastic in short order. The most effective containers to keep rodents out are made from metal.
Modern, plain clear glass Pyrex is completely non-toxic. However, older vintage colored bowls and patterned dishes frequently contain high levels of lead in their exterior paint.