It can sometimes be difficult to tell what can go in the microwave. Even things that look identical might no be the same, when it comes to microwaving it. It is useful to know which common households items can go in the microwave. Glass can heat up quickly and is often convenient when reheating or cooking food.
Many kitchen items are made of glass. It is natural to wonder if you can put glass in the microwave. Can you reheat food in a glass bowl? heat up a cup of tea in a glass? The answer is, unfortunately, it depends. Some types of glass can and others can’t.
Many times, it will be stamped on the bottom if it okay to go in the microwave. You have probably seen the symbol before. It is two squiggly lines. Although it is not always the case, so it can be worth knowing which types generally can go in the microwave. We will also show you how you can test this later in the article.
In this article we will go over the most important things you need to know when it comes to microwaving glass. We will go through some common types that can (and can’t) go in the microwave. We also mention some things you have to keep in mind, such as the temperature of the glass.
Can cold glass be microwaved?
We mentioned in the beginning, that the temperature of the glass plays a role. In general, you have to be careful when heating a cold or frozen glass. This is no matter if you do it with a microwave or otherwise.
Heating a cold glass too quickly can result in it shattering. This can be quite dangerous and should be avoided if at all possible. There are some things you can do to avoid this. Such as running it under water with a cold temperature and slowly using warmer water. We recommended doing this before putting it in the microwave. It only takes a minute or two, but can make the whole thing a lot safer.,
If you insist on microwaving it from the beginning do the following. Start with small intervals such as 10 seconds and see what happens. This will make the heating more gradual and allow you to check if the glass is about to shatter. If there is also food in the microwave, try to stir it every interval. This will distribute the heat more evenly, which can also help avoid the glass shattering.
In case all that is too much trouble, you can just leave the glass out for 5 minutes. This should raise the temperature a bit. Remember to wipe any condensation off of the glass, as that will affect the glass in the microwave.
Is Glass Microwave Safe?
The worst thing that can happen when you microwave glass, is that it explodes. This will only happen if you use a cold glass or a type not meant to go in the microwave. It is not a guarantee that it will happen. So just because it worked one time, does not mean you should try it again.
A quick test if you want to test a glass. If it can’t take you pouring boiling water in it, then it will also shatter in the microwave. You should also never microwave any empty glass container or cup.
Does glass melt in the microwave
There is no risk of the glass melting in the microwave. The heat it takes to melt glass is far higher than what any normal microwave can produce.
What kind of glass can you put in the microwave
By now you are probably wondering which types of glass can go in the microwave and which can’t. Below we have compiled a list of the most common types that can be microwaved:
- Anything that is stamped microwave safe
- Pyrex glass (but don’t heat it too quicky or it might shatter)
- Glasses that you have thoroughly tested
- Most tempered glass
The following can’t go in microwave:
- Glass with any form of color
- Glass with any ink on it (like writing) that is not specifically meant to be microwave safe
- Any glass with metal parts
- Glass ceramics
The lists are above might seem a bit vague to you. It can be hard to tell what type of glass your cookware is made of. Generally speaking, most things that meant to be used in cooking will be made of tempered glass. This also ensures that if it shatters, it will go into many pices and not big (and dangerous) shards.
Other common things such as glass plates, glass jars and other things are not quite as easy to tell. Many times if the glass jar is came with a product and not bought seperately, it can’t go in the microwave.
Why not every glass can be microwaved
You might wonder what makes different types of glass able to be microwaved. It has to do with how it is made and how careful the manufacturer is to remove air bubbles in the glass.
Usually when glass is made, there will be tiny air bubbles in it (that you can’t see). When you microwave it and heat up the glass, these tiny air bubbles will expand. If they expand too much the glass will shatter.
Tempered glass undergo a process to make this less of an issue and also to strengthen the glass. It will be more durable and not break into shards.
How to test if glass is microwave safe
Testing if some glass can go in the microwave can be a good idea. Although it is not 100% accurate, it can be a good indicator if the glass can be microwaved. If your glass is on our list of types not to put in the microwave, then don’t do it no matter what this test might suggest. Note that there is a risk of the glass shattering even performing this.
To do this you will need some glass that you know for sure can go in the microwave. Fill this with some water. A cup will be enough. Put this in the microwave along with whatever glass you want to test. Do not pour water in the glass you are testing. Microwave this for 30 seconds. Try to touch (or feel the heat from it) the glass you are testing. If it is hot (not just a little warm) then it is not safe to microwave. If you can’t feel anything after 30 seconds, you can try and give it another 30 seconds.
A short summary
You have hopefully learning more about which glass can go in the microwave and which cannot.
If the glass is specifically made as cookware, it will often be safe to microwave. In this case, the manufacturer sometimes stamps this on the bottom. If there is any metal, coloring or ink on the glass, it might not be safe.
You might still be in doubt, but you can find out with a simple test that we have described above. In any case, if the glass is very cold, you should always make it room temperature before you put it in a microwave.
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