Pyrex is the brand name of a type of glass cookware made from borosilicate and soda lime that comes in many sizes, colors and patterns. In recent years, Internet rumors claimed that Pyrex was more prone to shattering or exploding in hot ovens because Pyrex changed their recipe. However, Pyrex changed their glass recipe back in the 1940s. Dramatic Internet stories of exploded food-laden Pyrex casserole dishes only surfaced in the last decade.
How Pyrex Breaks
Pyrex is not invincible. It is a type of glass, remember. Glass breaks for two main reasons:
- Sudden dramatic temperature changes
- Damage to the Pyrex itself, even if that damage is microscopic
If you want to avoid your Pyrex shattering in the oven, then you need to avoid subjecting your products to extreme temperature changes and to avoid damaging them. Even scratches or thread-line cracks can cause uneven distribution of heat, which leads to extreme temperature changes.
Avoiding Sudden Temperature Changes
It’s easy to avoid sudden temperature changes with your Pyrex. Follow recommendations from World Kitchen, Pyrex’s manufacturer:
- Never place Pyrex directly from the freezer or refrigerator into an oven.
- Never place Pyrex into a cold oven and then turn the oven on. This is too much of for the glassware to handle. Always place Pyrex into a pre-heated oven.
- Never place a hot Pyrex product directly from the oven onto a countertop or table. Always place it on a towel, cooling rack or potholder.
- Never place a hot Pyrex product into the sink for cleaning. Let it cool off first.
- Never place Pyrex in a toaster oven, over a campfire or on a hot plate. This causes an uneven distribution of heat and may cause it to break. Yes, decades ago Pyrex marketed a popular line called Flameware but you can’t place Pyrex over an open flame or directly onto a heat source.
- Place water or broth on the bottom of a chunk of meat or vegetables like asparagus spears. Although lasagna will cover the bottom of the Pyrex dish evenly, a chicken will not. The water or broth helps create an even amount of heat.
Always check a piece of bake ware for damage such as chips or scratches before placing food in it. Obviously, dropping a Pyrex piece will damage it. But there are not-so-obvious ways of damaging Pyrex, including how to store and clean it.
Clean room-temperature Pyrex with dishwashing liquid and hot water. Avoid abrasive cleaners like bleach or wire wool brushes whenever possible because they can scratch. Never place vintage Pyrex (really, really old) in a dishwasher. Never heat up the Pyrex piece before cleaning it, notes Pyrex collectable website Pyrex Love.
Avoid piling Pyrex items on top of each other, unless they are designed to fit together, such as a set of three different-sized bowls. It’s best to store lids separately from the dishes or bake ware rather than stack the items on top of the lids. Pyrex Love notes that eBay sellers often show photos of their Pyrex items upside down. This can easily chip the tops.
- Snopes.com. “Exploding Pyrex.” http://www.snopes.com/food/warnings/pyrex.asp
- Pyrex Love. “Pyrex Care and Storage.” http://www.pyrexlove.com/pyrex-care-and-storage/
- Pyrex Love. “Pyrex Cleaning Tips.” http://www.pyrexlove.com/how-to-clean-pyrex/