Microwaves are a great way to heat up food and beverages, but there are a few things you should know when you're deciding which bowls or mugs to use. It's important to know how long it will take your item to heat up—and how long it will take for that heat to break the glass. To help give you peace of mind, here's a handy guide on the right way to check if your glass is microwave-safe:
Microwaves are tricky and it's easy to misjudge if a container is microwave-safe.
Here are some things to keep in mind:
- Microwaves heat up water. The purpose of the microwave is to heat up water, not food. Foods contain water, so they heat up too, but only because they're full of that hot liquid.
- Glasses and other items made out of glass can break when heated in a microwave. There's a reason why most dishes aren't made out of glass: it breaks easily! If microwaves cause glassware to shatter while heating water inside the dish, imagine what would happen if you tried heating your food in the same dish without breaking it into pieces first!
So how do we know whether or not our glasses are safe for use with microwaves? The easiest way is by using common sense: if you put anything that looks like solid metal or plastic (like an empty bottle) in your oven at home during baking time then do not put it into your microwave for heating purposes either - these materials don't take well being exposed frequently over long periods of time at high temperatures due their molecular makeup which can lead causing damage over time when subjected repeatedly exposed such conditions."
Microwave radiation heats up water, which causes the glass to vibrate.
That's why you shouldn't heat plastic containers in the microwave because they can melt. The same thing happens when you use a glass or mug that isn't microwave-safe: it breaks because of how much it vibrates while being heated by microwaves.
So how do we know if a glass is microwave-safe? There's an easy way to test it! Fill up your glass with water and place it on top of some paper towels in your microwave, then heat on high for 90 seconds (or whatever time necessary). If the glass doesn't crack, then congratulations – it's safe!
The thick the glass, the less likely it is to heat up and to crack.
In the first place, thick glass is more likely to withstand heat. It's a good conductor of heat and can take the temperature without cracking or breaking. A thin glass will crack or break at a lower temperature than thicker ones would.
Glass is one of the best materials for microwave-safe materials because it has low thermal expansion coefficient (it doesn't expand as much). This means that if you heat up a thick piece of glassware in your microwave, then let it sit outside your microwave for awhile and come back to check on it later, you'll find that it hasn't expanded like other materials would have done after being heated up so much at such high temperatures.
A good test is to put water in the bowl or mug and microwave it for one minute.
If the water is warm, but you can hold it without burning your hand, then it's probably fine. If it's cold, then it's not going to get hot enough to break. In that case, you'd be better off using something else with more substance (like a plate).
If your item is cold after one minute, it's not going to get hot enough to break.
In the case of glass and ceramics, your items will only heat up if they're already hot to begin with. To test whether or not an object is microwave-safe, put it in the microwave with a cup of water. After one minute, take it out and see if it's warm. If it's not warm at all after one minute (or even two), chances are you can safely use your item in the microwave without worrying about breaking it.
If you've tried this method but still aren't sure about how hot your object is getting, try using a digital thermometer to get an accurate reading on how much heat is being generated inside of whatever you're testing.
If it's warm, but you can hold it without burning your hand, then it's probably fine.
To check if a glass or mug is microwave-safe, first test with water. If you can heat a glass in the microwave and hold it without burning your hand, then it's probably safe to use for hot drinks.
Next, test with your hand. If you can hold a mug (or other object) for about 15 seconds in the microwave before it gets too hot for comfort, then it should be fine for heating up coffee or tea in the future.
Finally, heat up an empty dish or plate using the "microwave" setting on your microwave oven until there is no more steam coming off of its surface (about 10 seconds). Then remove from the oven and place a small amount of cold water into the center of this dish/plate; if this water starts to boil within one minute after taking out of oven then there should not be any problems with heating liquids like coffee/tea inside this container either!
The same process applies when testing glasses and mugs as well: fill them up with cool water—but not ice cold!—and place them inside your microwave oven at full power until they reach around 150 degrees Fahrenheit (65 degrees Celsius). Once heated thoroughly toss out any remaining liquid but keep these containers safely stored away so they don't lose their strength over time while being used regularly.
When in doubt, play it safe!
If your container is not marked as microwave-safe, don't use it in the microwave. Remember: when in doubt, play it safe!
And remember that microwaves can cause a lot of damage to other items besides your glass or mug. So if you're cooking something in the microwave, make sure there aren't any other plastic items nearby which could melt and stick to your food when they get hot.