Can You Microwave Glass? (Or KABOOOM?!?)

A microwave with glass plates next to it

You're smart to ask"Can You Microwave Glass?" before popping a glass dish into the microwave only to find out later it was dangerous and there was a chance of it exploding which at best will ruin your food and at worst damage your microwave...or you!

If you’re a lover of quick and easy meals or someone who loves to reach for leftovers in the fridge, then the microwave will be your best friend.

However, finding suitable storage or dishes to heat your food in the microwave can sometimes be a struggle. 

Glass from the outside seems like a great option for food storage, it’s fairly heat resistant, it can be easily shaped when creating it, it doesn’t react or leech into the food you're cooking in there and the transparent appearance allows you to see your food whilst it cooks.

You may have a tasty casserole leftover in a glass dish ready to be reheated, but you’ll need to read on to find out if it’s safe to go directly in the microwave or if you’ll need to find something else to heat it up in.

The short answer is "sometimes" but don’t get ahead of yourself and risk it before reading the whole article to make sure you’re in the green as not all glass dishes are created equal and you don't want a disaster on your hands...

Check your labels

Before microwaving anything in any glass containers, you’ll want to check the exterior of them or if you still have the original packaging, for any microwave safe symbols or labels.

If you’re unsure what this looks like, then it just looks like an outline of a microwave outline, or you can give it a google if you’re still unsure.

There may also be an engraving on the base of the glass dish which states whether it is microwave-safe or not.


We can’t determine that every glass item without a microwave-safe logo will be safe to put in the microwave.

Cheap and fragile glass items may not be able to withstand the heat of the microwave, so may shatter, so you may want to take note of the items you use before making any decisions. 

On the other hand, you can carry out this short experiment to see whether your glass items are safe or not.

Put some of the drink or food (we recommend using something you’re not hoping to eat) into a cup and then place the cup into the glass container (do not pour contents into the glass container) and put on high power for 1 minute.

Carefully feel the glass and the cup and if they are hot, then it is not microwave-safe and you should try to find something else.

If it is only the food or drink inside that is hot whilst the glass exterior is regular temperature, then it should be safe to use.

If you placed your cup into the center of the glass container, then the area around it may feel warm, this means it is still safe.

A microwave with glass plates next to it

Do Not Microwave Glass In This Instance...

If your glass dish has been in the fridge or freezer for a while then you should not put it straight into the microwave or into high temperature for that sake.

Glass is very vulnerable to temperature shocks, so going from a frozen temperature to scalding heat can cause the glass to crack and explode everywhere.

If you want to heat something up from frozen, then you’ll need to let your food in the glass dish thaw at room temperature and then put it in the microwave.

To speed up this process, if your glass dish has a cover, you could thaw it under cool water and slowly turn it warmer until it’s tepid (not hot), this will leverage the temperature without being such a drastic change.

Do not just place your glass dish into hot water to thaw, that will also cause it to split and explode (as Soup does in the microwave).

If you’re really stuck on time and dead set on using the microwave to thaw your food, then you can try and do so on the lowest power and removing it every minute or so to stir.

Do this until your food moves more freely around the dish and all frost is gone. If the dish still feels frozen cold on the outside, do not then put it on full power to heat up fully.

If your dish has silver, gold, or metal looking rims on the edges then we don’t recommend putting it in the microwave as it could cause it to spark and catch on fire.

What else should I not microwave?

If you’re going to use plastic containers then you’ll want to see that they are BPA-free and microwave safe before using them as they can change shape at high temperatures and if not chemically safe, can leach into your food and cause health problems.

Do not put any brown paper bags into the microwave as they will catch on fire and if left unattended could make your microwave catch on fire. The same goes for metal takeout containers, they will cause the microwave to spark.

If you want to reheat leftover takeout then place the food onto a ceramic or glass bowl and not in the takeout box. If you’ve got a styrofoam tray or takeout box then you will want to avoid putting this in the microwave as well. 

So Can You Microwave Glass Or Not? 

Once you’ve found out if your glass container is microwave safe, you can mark underneath with a permanent marker to save you some time in the future.

Ceramic and glass do tend to be the best options for heating up things in the microwave due to being fairly heat resistant and they also do not contain harmful substances like BPA (check BPA free steamers) that some plastic containers can.

There are brands out there that specialize in glass cookware that is suitable for the microwave, you could look at brands like Pyrex and OXO who offer everything from storage containers with lids to family-sized casserole dishes.

We hope this answered all your questions regarding microwaving glass.

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