Boiling Water in a Microwave - Dangerous

Received this email recently:

A26-year old man decided to have a cup of coffee. He took a cup of water and put it in the microwave to heat it up (something that he had done numerous times before). I am not sure how long he set the timer for, but he wanted to bring the water to a boil. . When the timer shut the oven off, he removed the cup from the oven. As he looked into the cup, he noted that the water was not boiling, but suddenly the water in the cup 'blew up' into his face. The cup remained intact until he threw it out of his hand, but all the water had flown out into his face due to the build-up of energy. His whole face is blistered and he has 1st and 2nd degree burns to his face which may leave scarring.

He also may have lost partial sight in his left eye. While at the hospital, the doctor who was attending to him stated that this is a fairly common occurrence and water (alone) should never be heated in a microwave oven. If water is heated in this manner, something should be placed in the cup to diffuse the energy such as a wooden stir stick, tea bag, etc... , (nothing metal).

GeneralElectric's Response:

Thanks for contacting us, I will be happy to assist you. The e-mail thatyou received is correct. Microwaved water and other liquids do not always bubble when they reach the boiling point. They can actually get superheated and not bubble at all. The superheated liquid willbubble up out of the cup when it is moved or when something like a spoon or tea bag is put into it.

To prevent this from happening and causing injury, do not heat any liquid for more thantwo minutes per cup. After heating, let the cup stand in the microwave for thirty seconds! Before moving it or adding anything into it.

Here is what our local science teacher had to say on the matter: 'Thanks for the microwavewarning. I have seen this happen before. It is caused by aphenomenon known as super heating. It can occur anytime water is heated and will particularly occur if the vessel that the water is heated in is new, or when heating a small amount of water (less than half a cup).

What happens is that the water heats faster than the vapour bubbles can form. If the cup is very new then it is unlikely to have small surface scratches inside it that provide a place for the bubbles to form. As the bubbles cannot form and release some of the heat has built up, the liquid does not boil, and the liquid continues to heat up wellpast its boiling point.

What then usually happens is that the liquid is bumped or jarred, which is just enough of a shock to cause the bubbles to rapidly form and expel the hot liquid. Therapid formation of bubbles is also why a carbonated beverage spews when opened after having been shaken. '

If you pass this on you could very well save someone from a lot of pain and suffering.

Wow. . Thanks for sharing...

The information in this email can be considered a valid warning for microwave users. However, like many email forwards of this nature, it also contains anecdotal information that lessens its credibility. The "26-year old man" is not identified, nor is the "local science teacher". There is no way of verifying if these are real people or just fictional constructs added to drive home the point. Also, there is no way of confirming if someone from General Electric actually responded in the manner outlined since no name or contact details are supplied. Unfortunately, this unverifiable information, along with the dubious exhortation to "pass on" the message, may convince some recipients that the email is just another bogus warning.

In spite of these factors, microwave users would certainly do well to heed the advice in the email.

ferita, I agree with the points you are making. However if these types of "warnings" makes one aware of dangers or such(depending on the message) then people can use their own judgement. I often put jars of water in the microwave to help get the labels off. I think I will find a little wooden spoon to put in it from now on!

It appears that this is indeed true!

http://www.snopes.com/science/microwave. asp

Yip true from experience, as the cup sides are smooth the bubbles have nothing to form against, so once the energy get to a certain point it just "jumps". Have you noticed that you can get bubbles forming in liquid a lot quicker if you leave a spoon in it or move it? ? ? ? ? ?

reminded me of the time I took an aconite mug out of the microwave and it shattered.

I opened the door, microwave stopped and put my hand in with a metal bangle on my wrist and BANG!

Regardless of the anecdotal elements of the first posting, the warning concerning liquids heated in a microwave is perfectly valid. I have seen this happen several times, thankfully without causing injury to anyone.

I have also known the same thing to happen when making fudge in a microwave and of course, any mixture containing a large quantity of sugar can cause severe injury and possibly permanent scarring.

Thank you for posting this in the Recipes board, lulu239. We all need these reminders occasionally.

Excellent information lulu. You need to be congratulated for bringing itto the attention of anyone who reads this thread. I have long known how dangerous boiling cups of water in the microwave can be when I saw a work colleague get her hand totally burnt. It was many years ago now and there was no internet to go and ask why so knowing the reason for that event is most illuminating.

My colleague took her cup out and put in a metal spoon and the whole lot just blew up in her hand.