Warning! Water Can Explode in the Microwave

Exploding Water in the MicrowaveHeating water in the microwave can actually be dangerous. A man decided to have a cup of instant coffee, so he heated a cup of water in the microwave. When the timer went off, he removed the cup from the microwave and noticed that the water had not boiled. Just then, the water literally “blew up” in his face. His whole face was blistered with first and second degree burns, which left some permanent scaring and damage to his left eye. While at the hospital, the doctor attending him stated that his is a fairly common occurrence. Water (alone) should never be heated in a microwave oven. Why?

Read the full explanation of Exploding Water in the Microwave

This phenomenon is known as superheating. It can occur anytime water is heated – especially if the cup or bowl is new. What happens is that the water heats faster than the vapor bubbles can form. If the cup is very new, then it is unlikely to have small surface scratches in it that provide a place for the bubbles to form (called nucleation sites). Without bubbles, the water cannot release the heat that has built up, the liquid does not boil and it continues to heat up past its boiling point. If the water is bumped or jarred, it’s enough of a shock to cause the bubbles to rapidly form and the result is an exploding liquid that is scalding hot. One solution is to place a wooden stir stick or something non-metallic in the water to help diffuse the energy as it’s heating in the microwave.

While sharing this story with audiences, I’ve learned that many people have had similar experiences but never understood why the water just blew up. It’s an important piece of science to share with others in hopes of preventing a potential disaster.

44 thoughts on “Warning! Water Can Explode in the Microwave”

  1. Hmmmm… Ive heard of this before but i didnt belive that it could actully happen. So what that says that if a new cup is used to heat water its lickely that the water will explode. This is very interesting I think ill look upon this

  2. This just happened to me today at work! Heated up a mug for tea, noticed it wasn’t boiling and boom- right up the left side of my neck and face. About 2 tbsp of water left in the mug. True! Stopping for aloe vera on the way home.

  3. dont know if its true..but will find out …is microwave a health risk? i always use it to make tea..but lookin at u.s.a where baby boomers and society has grown up on microwave food, i dont see them affected now in life..those who used it in the 1980’s in usa japan etc..so doubt tht my mom is correct in saying microwave heating is bad for you, with the radiation etc..

  4. Not sure about microwave ovens posing any health risks. I’m sure there’s plenty of stuff on the internet on both sides. Sorry I don’t know more about it.

  5. This is absolutely true! I have seen it happen. I have also had it happen to me. The first time it happened, it wasn’t water… it was soup. Bell went off, microwave stopped running. Opened the door, grabbed a napkin and some crackers, spoon. Then reached in to grab the soup, touched the little handle of the edge of the cup and blam, with 10 or 11 other employees watching, the soup shot straight up, covered the entire inside of the microwave, flooded out the front. Second time was just water in prep for ramen noodles. Same thing, touched it and sploosh, boiling water everywhere… burned me and actually shot out of the oven onto my shirt, pants and shoes.

    Believe it or you’ll likely pay a price for ignorance.

  6. I’ve had this happen. Scared me to death! I’d never heard of it before. I wanted to boil a cup of water, and I set the timer for 2 minutes. At the end, it hadn’t boiled at all, so I added more time. It still didn’t boil. I was looking through the window on the door to see if it was boiling, and all of a sudden… BOOM! It was enough force to fling the microwave door open. The cup jumped up and hit the top of the microwave, the sat back down straight up. It never turned over, but it was empty. All of the water shot out violently inside the microwave, and much of it sprayed out through the open door. I’d never seen anything like this before! That’s why I came to the internet to search to find out why this happened. Apparently, it’s fairly common! BE CAREFUL!!!

    1. The same thing happened to me!The microwave no longer works. I was concerned about leaking radiation. Do you know if it’s possible that radiation could have leaked out from the microwave because of this explosion?

  7. Interesting phenomenon…it works with eggs too as I found out! Wanna try, take a styrofoam cup, crack an uncooked egg into it, discard the shell, microwave on high for 1 minute…in approx 45 seconds, your microwave will be goo-ed with half cooked egg matter…enjoy!

  8. This just happened to me. I put 8oz of water into a pyrex glass microwaveable jug and I heated it for about 3 minutes. When I opened the microwave to remove the water I noticed it was not boiling. I didn’t think much of it, so I reached in and picked up the jug by the handle. The water exploded out of the jug and scalded my arm. I never knew this could happen. I have now learned from reading in the internet to put a wooden spoon in the water to prevent this from happening.

  9. Diana — I going to have Dr. Gordon Linberg who is a burn specialist on as a guest on 9NEWS on Monday to discuss this very issue. I’ll be sure to post the streaming video on the blog.

  10. This is a real problem. The American Burn Association (ABA) has identified scald burns from superheated liquids in microwaves as a target for a new public awareness campaign. These burns are dramatic and traumatic because they often affect the face and hands of the burn victim. Fortunately, these burns rarely need grafting; however, they are extremely painful and in children these burns often lead to hospitalization for wound care and pain control. The best way to avoid these burns is to place a wooden coffee stirrer in the liquid when heating it and also to let all heated liquids cool for a few minutes inside the microwave before removing them.

    If you receive one of these burns, and especially if it covers the face or hands, seek a burn care specialist for care. Initial treatment for the burn can be performed in an ED or at a doctor’s office, but a burn specialist should see the burn within 24-48 hours after the injury, especially if the face is involved. If the eyes are involved, an ophthalmologist should be consulted immediately. Both burn units in the state of Colorado are open 24 hours a day/ 7 days a week/ 365 days a year. There is one in Greeley, CO and one at the University of Colorado in Denver.

  11. This is not an “urban myth”. It’s real and it’s painful. My son-in-law had to go every day to get his wound cleaned and rebandaged, then every other day.
    We took a picture of the burns on his hand right after it happened. I posted it on my blog, feel free to check it out. Not pretty!

  12. This phenomenon is not merely confined to the microwave but it could also happen on the stovetop or whenever you are heating a very pure liquid up.
    Tips: Avoid heating up either distilled or de-ionized water. These types of water have less ionic content than normal tap water. If your dish can stand it, put some salt in before boiling, this will increase the ionic content of the water and make it less likely to superheat.

  13. I’ve never heard of this before, but why can’t people just not super-heat their water? Why does tea or coffee or soup have to be SO hot?

  14. my daughter was making a poached egg in the microwave today when she took it out it blow p on her face she has blisters and her two eyes are burned we are just going up to the hostpital. she is in so much pain.

  15. This happened to me at work this morning. I had already heated a cup (not new) of water but forgot about it. When I finally went back to the microwave I had to reheat the water as it was only warm and not hot enough for my tea. I set the microwave for two minutes and was watching the cup so I could stop the microwave when I saw the water start to boil. At about one minute of time the water exploded out of the cup. I had never seen anything like this happen before and I have been boiling water in this manner for years.

  16. My son stuck a hard-boiled egg into the microwave to heat it up, and the egg exploded. Thing is, the microwave itself blew a fuse or something and there’s no power now. There’s no reset button, or anything. Anyone have any ideas?

    Thanks, if you do.

    Mike.

  17. My son put a hard boiled egg into the microwave to heat it up (no shell). The egg exploded with a terrific bang. Now the microwave has no power. There isn’t a reset key or anything. Any suggestions? Thanks in advance.

  18. I have also had this happen to me but not with water. I was heating up milk to make creamy cocoa. I was standing there waiting for the bubbles to start so that I would know when the milk was hot enough to add the chocolate powder into it. It never did boil so I opened up the microwave to see if it was hot enough by stirring the milk using a metal spoon. I guess the milk had formed a skin on top that did not let the heat escape and when I stuck the spoon into the milk it shot straight up out of the mug onto my hand and the inside top of the microwave and down onto the turntable. It scared me to death but fortunately it only burned a couple fingers and that’s all. I have never heated milk up in the microwave since.

    1. this happened to me this morning, put a cup of milk in, but it didnt boil, so i gave it a bit longer, when i took it out it looked like the milk had seperated, i put a spoon in to stir it but it just exploded in my face.. quick reactions was to put cold water on the burns, got a couple of small blisters, but i guess it could of been a lot worse..! wont be doing that again..

  19. For anyone who thinks this cannot happen, my wife is presently at an Eye Surgery center with her mother. Her mother was removing a cup of microwaved water behind me in the kitchen, when the cup exploded, leaving steaming water and embedded shards of glass in the ceiling and walls. My wife just called from the hospital to say that her mother has lost her right eye totally to the flying glass and scalding water and her left has but a minor chance of recovering from the scalding should a cornea transplant become feasable sometime in the future.

  20. This happened to my father on the weekend, but with milk! He put his mug in the microwave with cold milk, like he has done for a long time. He saw it starting to bubble so stopped the microwave, reached in and took it out and as he did it exploded, scalding his forehead and a little into the scalp!
    The mug was still in tact and my father is currently in seeking medical assistance for his burns.
    Yes, indeed it does happen and not just with water!

  21. I was boiling and egg this past week and decided to use my microwave to do so. I cracked the shell and made a small hole so the egg would cook completely. Well when I went to take the egg out I saw that a soft spot in the egg was kind of pulsating. Now I figured this was just because water had actually gotten into my egg. So I took the tip of a knife with the plan to poke the spot and let out the water. The egg was still in the water i had boiled it in. Before I could think twice the tip of the blade touched the egg and it blew up in my face. I now have first degree burns on the right side of my face as well as second and first degree burns on my right hand and upper and lower right torso. Just an FYI for those who still think if you crack the shell after its started to boil to release the build up thats a LIE!!! Please note even though the microwave company’s have yet to have the warnings placed hard boiled eggs don’t get made in it. EVER!!!

  22. This just happened to us over Christmas !! We filled 1 cup of water in a 2 cup (glass) container. The glass container was not new. The water did not boil, so we started it again for 30 more seconds. The water exploded, still in the microwave, blew the door wide open , and water was everywhere in the kitchen. Could have been a very dangerous experience for us. We learned a great lesson.

  23. Water just exploded in my microwave..
    I had water in there and boiled it just fine, and while it was heating, I went back to my room and forgot about it.. I came into the kitchen a few HOURS later, noticed the water in there.. Picked up the cup, swirled it around a bit, and put it back in for the usual time.. I go back to preparing the thing that needed the water when I heard a BOOM. Before I turned around, I already knew what had happened. My water’s exploded before after heating a second time. I just figured that it was over heated.. This time, since it was there for HOURS, I didn’t think it would happen again. Well, it did. So I came to the internet in search for an answer.

  24. This just happened to me. I was microwaving water (filtered) in a Pyrex measuring cup to make couscous. It hadn’t boiled in the time I expected it to so I set the microwave for another 20 seconds. It still hadn’t boiled, but I figured it must be hot enough so I took out the cup and poured the couscous in. Immediately it exploded: boiling water and couscous scattered all over the kitchen and all over me, hardly any was left in the cup. Thankfully I had my glasses on; the boiling water spattered against my glasses. I received minor burns to my hands. I won’t be trying to boil just plain water in the microwave anymore — will either add some salt or a wooden stirrer to it.

  25. Hi steve, i was curious if you knew what it was that caused DI water to explode. It was brought up in a safety training video but that video is out of date. I work in a laboratory and was curious how someone figured that out. I want to say it had to do with cleaner or fire extinguishers, but i can’t recall.

  26. I had a similar but different experience with this. I was swapping out an old microwave with a new one. As a cleaning trick I learned, I put a corelle bowl filled with water to boil it to steam the insides of the microwave for easier cleaning. It worked fine, I saw the water boiling after about 2 minutes when I stopped the timer, took the bowl out and cleaned up the old microwave with ease.

    Next, after swapping out the old microwave with the new one, I put the same bowl with the same water (which was now cold) in the new microwave to clean it too. In less than a minute the water exploded inside the microwave while it was still running. I was worried that I had a defective microwave before reading this site.

    Apparently the first boiling made the water less able to release its vapor the 2nd time around.

  27. I have been looking for un answer after my incident with boiling water in a Pyrex cup.It is really dangerous to boil water in a microwave. I just boiled water as usual and for the first time the water in the cup exploded to the point that opened the microwave door and it almost hit me. Lucky I was by myself at the kitchen.

  28. Wow! isn’t it amazing how many people have experienced exploding water since this phenomenon was posted.

    Guess what, just this very morning, my microwave oven started vibrating when I had radio one on and it wasn’t even switched on.

    And only 30 minutes ago, I heard music coming from it.

    Has anyone got any idea what’s happening?

  29. I just had this happen to me a few minutes ago. I was microwaving a cup of water for coffee in a just-washed glass and it exploded on me when I tried to take it out. Luckily, the water only left light burns on my arms. Now I know what causes this and I’ll make sure to pay attention next time!

  30. This happened to me last night. I have boiled water alot in the microwave thousands of times. I used a white corningware container. I usually use a glass container, like a measuring cup. I was going to make some tea. It didn’t even boil, but was hot enough, but took it out anyway, turned around and boom. It burned my neck, chest area, under my chin, around my lip area, on right side of my eye. I wear glasses and water was all over my glasses, but one drop must of gotten in my right eye, cause it was bothersome through the night. I used aloe vera cream with a pain pill and it helped. This morning it feels like a sunburn, but no blistering. Thank God. I will be using a tea kettle from now on.

  31. this happened to me Saturday night. I was heating up water in a pyrex measuring cup (not new). The water didn’t boil. When I opened the door of the microwave, it exploded, hitting me on the right side of my face/forehead and left shoulder. I immediately wrapped ice cubes in a dampened baby soft washcloth and started dabbing my face. My face didn’t blister; however, the water that went through two layers of clothing (fleece and knit) made a blister on the top of my shoulder. It was a miracle that I didn’t suffer more severe burns, which I credit to the application of those ice cubes!

  32. A dangerous yet amazing phenomenum
    Just a hunch, but I suspect the not-new cups had been washed in the dish-washer, making them very clean (very low contaminent levels)and the water may have been filtered (or milk very low fat).

    Perhaps people can confirm this?

    Strange how this is most common for thos who heast the liquid for a second time (in one case with hours between).

    Surely either the energy of the erruption could be harnessed (on a larger scale) or the ability to produce and contain superheated water without high pressure can be exploited by the power industry??

    Quick – Run to the patent office!! ;)

  33. Just this morning i had this happen to me. so i was putting the water i use for my oatmeal. same old flow. when i microwaved it the first time it bubbled,then stopped. i took it out and drained the water. i refilled the measuring cup and put it back in. so i microwaved it AGAIN for six minutes. it was not doing any thing. HOWEVER, when it was three minutes into it the water suddenly spontaneously evaporated and the microwave door slammed open. scalding hot water got ALL over the place. i got a little burn mark on my hand. i cleaned it up and i did not have any breakfast,sadly :( and get this: my dad blames i put something in the water to make it do that. i did not. i don’t get it. i always put in water in the microwave for six minutes. i don’t see why it would do that now. gosh, i am ticked off at my dad for blaming me for what the microwave did!! ):< I used the measuring cup a hundred times for this purpose and it NEVER DID THIS BEFORE!!!!

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