The microwave is one of mankind’s greatest achievements. Bringing something from cold to hot in a matter of minutes or seconds makes it easy to cook meals, heat leftovers, and save time. That said, you can’t just put anything in the microwave. So, you might be wondering: can you microwave glass? The short answer is yes, you can microwave most glassware in the microwave.
Unfortunately, it’s not always a simple yes or no. In fact, there are situations where you should never microwave glass. It comes down to what type of glass it is, if the glass is colored, and how cold the glass is before placing it in the microwave. The good news is that we’re here to help. We’re going to take you through everything you need to know about microwaving glass, this way you don’t end up with a microwave full of glass shards.
Read on to learn more.
What Types of Glass Are Microwave-Safe?
Most types of glass designed for cooking and eating are microwave-safe. The best way to know if the glass is microwave-safe is to check if it has the microwave-safe logo. The logo resembles a microwave with a few curvy lines that represent heat. If the glass item you’re looking to microwave has this logo it’s safe to use in the microwave.
Is Regular Glass Cookware and Bakeware Microwave-Safe?
Regular glass cookware and bakeware are typically microwave-safe. To determine if it’s safe you can check to see if it has the microwave-safe label. Most glass items for eating, cooking, and baking will have the microwave-safe logo. The only time these items are not microwave safe is if the glass contains air bubbles (they can expand when heated and shatter glass). If you’re not sure if your glass item has air bubbles you can use our simple test below to find out.
Is Colored Glass Microwave-Safe?
When glass is colored with dyes and other chemicals it’s not safe to microwave. When heated chemicals within the glass can enter your food and contaminate it. While this won’t cause your glassware to shatter, it can lead to health risks associated with cancer. That said, some dyes can add air bubbles into the glass that causes it to expand and crack heated.
Is Pyrex Glass Microwave-Safe?
Pyrex glass is safe to microwave. It’s made from soda-lime glass, which can handle rapid changes in temperatures and prolonged exposure to high temperatures. In fact, pyrex is one of the best glass types for ovens because it can handle the heat for hours on end without cracking or shattering.
Is Glass With Metal Trimming Microwave-Safe?
If you have glass plates or cups with metal trimming you should never put them in the microwave. Metal-trimmed glass is not safe for the microwave because the metal can cause sparks. Depending on the type of food you have in the microwave this can lead to fires and other dangers.
Most types of glass used for cooking and eating are safe but we always recommend checking for the microwave-safe logo or using our glass test below.
Microwaving Frozen Items on Glass
Microwaving frozen items on glass is dangerous if not done properly. While synthetic glass (Pyrex) and traditional glasses for cooking and baking are safe to put in the microwave, rapidly changing their temperature can cause the glass to shatter.
Instead of putting frozen items directly into the microwave on a glass plate, make sure you let what you’re microwaving defrost in the refrigerator. You don’t need to have it reach room temperature but it’s best to make sure it’s not frosty entering the microwave. Another method to defrost the glass quickly is to place it in an inch of water. The water will transfer heat to the glass and help it reach room temperature faster.
We always recommend avoiding taking the glass from the freezer and placing it in the microwave. While it seems convenient it can leave you with a mess to clean and possible injuries if you’re not careful.
Can Microwave Melt Glass?
Microwaves can’t melt glass. The melting point for glass is between 900 degrees Fahrenheit and 1,600 degrees Fahrenheit. Microwaves don’t have the power to produce that much heat. You can put glass in the microwave for hours (if you have the time) and it won’t melt.
Glass is suited to handle high temperatures and cold temperatures. You’ll only encounter problems if you change the temperature of the glass rapidly.
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Microwave-Safe Test for Glass
You can typically learn about whether or not glass is safe for microwaves from the logo but some containers might not have the logo or it could be hard to see. While checking for the logo is the best way to tell if the glass is safe, there is a home test you can do yourself to determine how well the glass will hold up in the microwave.
It’s a three-part test that shouldn’t take you more than 5-10 minutes.
The first step is to find glassware that you’re unsure about. If you have glassware that doesn’t have the microwave-safe logo it’s a good candidate for microwave-safe testing. Feel free to test plates, bowls, mugs, and anything else you’re curious about. That said, we recommend sticking with cooking or baking items because not all glass is made the same. Glass used in other products might contain air bubbles that expand and shatter glass when rapid temperature changes occur.
For the next step, you’ll want to turn your microwave up to its highest heat setting. Most microwaves use wattage to determine how hot they get. The average wattage range on microwaves you’ll find in homes is 600-1,200 watts. Depending on what microwave you have, your highest wattage setting will vary. As an example, if you have a 1,200-watt microwave make sure it’s turned up to 1,200 watts.
The next step is to grab another glass item. With the second glass item, make sure it’s microwave safe so you don’t have any unexpected variables in the experiment. Fill the glass up with water and place it on top of the glass item you’re testing.
Once you have both items, place them in the microwave on the highest setting. While you can use whatever time you desire, we recommend setting the timer to one minute or less (to prevent the glass from shattering if it’s not microwave-safe). Let the microwave run its course and then remove both glass items from the microwave. If the glass filled with water is hot and the glass piece that it’s resting on is also hot then it’s not microwave-safe. On the other hand, if the glass of water is hot but the plate is cold then it’s microwave-safe.
Testing glassware this way is safe, effective, and reliable.
The microwave is a staple item in almost every kitchen. It makes cooking hassle-free and saves you time and energy. That said, you need to handle your microwave and glass cooking items with care. Placing the wrong type of glass in the microwave can ruin your meal, damage the microwave, and cause injury if you’re holding it.
If you’re ever unsure about a glass item’s safety in the microwave make sure to use our test.
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