Yes! You can microwave glass. However, not all glassware is microwave safe. In general, what you wanna look for is a microwave-safe label that indicates that the food storage is made of heat-resistant glass that can handle extreme heat and sudden temperature change.


Read here to find out whether you can microwave tupperware.


Can You Microwave Glass - Pyrex food container


Is Glass Microwave Safe?

The easiest and safest way to figure out whether or not your glass food storage or utensil is safe to use in microwave is by referring to the manufacturer’s label or instructions. Most anything you can buy will have a clear text or symbol that definitively identifies a microwave-safe glassware.


If there’s no clear indicator that the item is heat-resistant, then we strongly advise making bold assumptions. If the label is unclear or missing, then do not risk using the said glass to heat food or prepare a special dish with your microwave.


Can You Microwave Glass - microwavable glass containers

What Type of Glass is Microwave Safe?

Manufacturers widely use Borosilicate glass to make microwave-safe glass dishes. Notably, the well-known glassware brand, Pyrex, uses a blend of Borosilicate to make its microwave-safe products.


Tempered glass and soda-lime glass, which account for 90% of the world’s manufactured glass, are also safe for microwave use. However, since they don’t have the durability and resistance of Borosilicate glass, these two are only recommended for reheating food.

What Kind of Glass Can You Not Microwave?

Virtually any other type of glass that isn’t Borosilicate is questionable for microwave use. And so, when in doubt, look out for the microwave-safe labeling from the maker before further microwave application.


Can You Put a Cold Glass Dish in the Microwave Oven?

You can typically microwave cold glass that is labeled microwave-safe. For precaution, you can let the glass container reach room temperature before offering it up to the microwave oven. What you want to avoid here is putting freezing glass containers through your microwave. This can lead to unpredictable reactions that can damage your glassware or the oven itself.


Can You Microwave Glass - microwave-safe glass bowl, container

Will Glass Break if You Microwave it?

Over-exposure to microwave radiation will certainly break most types of glass dishes. The exception would be Borosilicate and microwave-safe tempered glass which have stronger resistance, and therefore, can withstand more rigorous microwave use.


On the other hand, you may encounter glass with tiny air bubbles trapped in the surface. For the record, this can mean that the glass didn’t cool off evenly, which led to some sort of imperfect or vulnerable finish. While the glass is safe for general use, we advise using it to reheat food in your microwave oven.


How Long Can You Microwave Glass For?

It varies on the type of cookware and material, but in general, you can use your microwave to prepare or reheat food for up to three (3) minutes.


Can You Microwave Glass - Standard household microwave

How to Know if Glass is Microwave Safe?

For starters, examine the labeling and instructions provided by the manufacturer to know if your glass containers are safe for microwave oven. In the absence of such references, you can perform a simple test.


To begin, fill the glassware with water and microwave them for at least thirty (30) seconds. If the glass stays cool to the touch and the water is slightly warm, it’s likely safe to use in the microwave. Otherwise, if the glass becomes hot, remove it immediately and avoid using it with the oven.


Can You Microwave Mason Jars?

A lot of new mason jars these days are classified as microwave-safe, but since older versions may be made of weaker glass, it remains optimal to check the label to verify whether your item is indeed safe for microwave use. As a reminder, you should keep the jar open when using a microwave to reheat food.


What are Mason Jars?

Mason jars are essentially glass jars used for food preparation or as drinking glasses. On a side note, these jars are also used as decor to emulate a vintage or rustic aesthetic. Mason jars are often mistaken to be made of tempered glass, although they are, in fact, made with annealed glass, which has weaker properties. Still, you can use mason jars with a microwave for simple reheating or cooling purposes.


Freezing Food in Mason Jars

You can freeze food in mason jars although you may want to refrain from filling it to the brim since food can expand under freezing temperatures.


If you plan to microwave the frozen food for later, it’s important to first let it thaw overnight before placing it in a microwave. Placing frozen glass in the microwave oven can cause the item to crack or even explode.


Conclusion on Microwaving Glass

A microwave oven is a quietly powerful kitchen appliance that must be handled with care at all times. While it’s tempting to microwave glass tupperware or any glass bowls that we first set our sights onto, we have to remember that an eye test is never enough to determine whether a glassware is microwave-safe or not. As such, it’s always in our best interest to check product labels or do a simple 30-second water test to make sure that our dishes are safe for subsequent microwave application.


Read here to find out whether you can microwave ziploc bags.