Pyrex is a popular brand of glassware that has been around for over 100 years. When it first became famous, Pyrex glassware was primarily used to make ovenproof dishes and containers for food storage. But now, with the rise in popularity of microwaves and instant gratification, people are asking if cold pyrex that’s been sitting in the freezer can be microwaved right away?
This blog post will go into detail about whether or not this is possible and what might happen if you do try to microwave cold Pyrex.
Can You Microwave Cold Pyrex?
As a general rule, you shouldn’t microwave cold pyrex. This is because, like any glassware, Pyrex glassware is susceptible to thermal shock. This means that sudden temperature changes can cause the glass dishes and containers to crack or shatter. Added to the fact that today’s Pyrex is made with tempered glass, not borosilicate glass, this makes it more susceptible to an abrupt temperature change.
Originally, Pyrex glassware products were made with borosilicate glass, which makes them much more resistant to thermal shock than tempered glass. This makes borosilicate glass safe to microwave. But at some points in the past, the manufacturer changed their formulas and has started using tempered glass to make their products.
The reason why the company changed over to tempered glass was unknown, but it is likely because borosilicate is much more expensive to produce and difficult to dispose of. The fact is that many companies have made this same change with their glassware products, so it’s not something unique to Pyrex products alone.
Although tempered glass can handle thermal shock better than regular soda-lime glass can, it’s not as durable to such stress as borosilicate. When placed under thermal shock, tempered glass can crack and shatter much more easily than borosilicate can.
This means you should never place cold pyrex glass from the freezer directly into a microwave oven or preheated conventional oven; vice versa, never place a hot Pyrex dish directly in the freezer.
Is It Safe to Microwave Pyrex Dish?
Contrary to microwaving cold Pyrex, it is okay to microwave a Pyrex glass that has been sit at room temperature for some time. The company itself has backed up this claim by saying that its products are made to be used in microwaves and can be heated up without any problem.
If you’re unsure about the safety guidelines of your particular glass Pyrex dish, you can find information right on the bottom of your product. All Pyrex products have a marking on the bottom that says whether it’s microwave-safe or not.
Is It Safe to Microwave Food in Pyrex Glassware?
According to the manufacturer, all of its products are BPA-free. The FDA itself has determined that tempered glass, the material used to make Pyrex, is Generally Regarded As Safe (GRAS). GRAS designation indicates that experts have determined that the products have no side effects on human health and are safe to use.
Although microwaving food in glass Pyrex dishes is generally safe, it’s still important to be mindful of how you handle your foods to keep them safe.
Referring to the USDA, to keep bacteria at bay, within 2 hours of microwaving, you should ensure no food has been left. If there are leftovers, they must be refrigerated right away. Throw away anything that has been left at room temperature for longer than 2 hours. (1)
Different Types of Pyrex Dishes and Their Microwave Safety
Pyrex has a number of different products that include glass dishes, bowls, and even vintage dishes. Here’s a rundown of what you can and can’t put into a microwave.
Pyrex Glass Jug
Pyrex glass jug is probably the best dish from the Pyrex collection that you can use in microwaves due to the borosilicate material that it was made from. This makes the product stronger and more resistant to thermal shock than other Pyrex products.
It features a convenient handle that offers a sure grip, which will keep you from spilling your products. The glass jug also comes with a lid to keep your food in the fridge or freezer fresher for a longer period.
The lid can also be used as a convenient way to transport your meals with ease. In addition, it is easy to clean and a necessity for anyone that loves cooking with Pyrex glassware products.
There are many Pyrex glass bowls that will work great in your microwave for heating up your food. Clear Pyrex glass bowls are the best options because they’re somewhat transparent and allow a peek into what’s cooking inside without having to open the door and steam up your kitchen.
Pyrex glass bowls come in a variety of sizes and shapes. Some are shallow, while others have higher sides for holding different types of food or for when you want to use them as serving dishes. All can be placed directly on microwave racks.
Some Pyrex bowl lids do have lids with them, and most of these lids are microwave safe.
Most of these vintage Pyrex dishes have been made from borosilicate. As I stated earlier, this type of glass is much stronger and less prone to thermal shock than the newer Pyrex. Furthermore, vintage Pyrex is usually made much thicker than its modern counterparts.
How Do You Microwave Cold Pyrex?
There would be nothing worse than cooking something in your microwave, only for the Pyrex dish to crack and splatter your food all over the inside of your appliance. If you are microwave a cold Pyrex product, the chances are that it will most definitely crack or even explode, leading to some hot mess in your microwave.
So if you’re going to be using Pyrex dishes as containers or to reheat cold food, the best way to microwave cold pyrex is to let the chilled container come up to room temperature. This will ensure that it is heated gently rather than allowing the dish to heat up rapidly and risk thermal shock from sudden changes in temperature.
Safety Tips for Using Pyrex Glassware
Here are some tips for handling Pyrex glassware dishes.
- Bring to room temperature. If you are going to be microwaving cold Pyrex dishes, make sure that they have been brought up to room temperature. Let it sit out for a while, while you are preheating the oven or the microwave to make sure that they warm gradually and won’t crack from thermal shock.
- Avoid placing hot glass dish directly on stovetop. Many stovetops include a metal plate between the burners and the surface of the countertop to protect it from heat damage. Although stovetops are designed to withstand heat, placing hot glassware directly on the stovetop may result in breakage. To prevent this from happening, you can place your hot Pyrex dish on top of a potholder, cooling rack, or dry cloth before placing it directly on the stovetop.
- Never microwave an empty Pyrex cup. I know this may seem like an obvious one, but just to be sure you know it: never microwave a Pyrex cup without anything in it.
- Don’t use glass cookware for high heat cooking. Glass is not the best material for cooking dishes that require high heat since it can break easily if you are cooking something that requires high temperatures. This involves cooking with a stovetop, broiler, and toaster oven.
- Don’t pour hot liquids directly into Pyrex glass. This is one of the cardinal rules of using glassware. If you are pouring hot liquids into Pyrex glass, you run the risk of cracking your glass!
- Don’t place hot glassware on a cold surface. This is another one of the cardinal rules for using glass. If you place hot glassware on a cold surface, it may crack due to thermal shock that occurs when two different temperatures meet.
- Check for cracks before putting your Pyrex in the microwave. Check every time you use it to make sure that your Pyrex dish doesn’t have any cracks. I know that most of us don’t want to do this, but it’s better to be safe than sorry by checking every time to ensure that your Pyrex dish is in good condition.
- Be aware of oven temperature and power levels. When you are heating Pyrex in the oven, be aware of the oven temperature and power level. Pyrex recommends that your dish shouldn’t be heated at more than 450 degrees F, anything more than this will cause the glass to break.
- Don’t cook a dry dish in Pyrex glassware. A good rule of thumb is to always add a little bit of liquid (even if it’s just a little bit) to protect the bottom of the Pyrex dish from getting too hot.
- Use oven mitts to handle hot cookware. Whether you are using Pyrex dishes or any other kind of cookware, make sure that you use oven mitts to handle hot cookware.
Can You Microwave Pyrex Lids?
It’s safe to microwave Pyrex lids since they are made of the same material as the dishes and containers they sit on.