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Author Topic: Why do eggs pop in the microwave?  (Read 14661 times)

KG Marite

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Why do eggs pop in the microwave?
« on: 21/11/2011 01:01:01 »
KG Marite asked the Naked Scientists:
   
Hey Chris

I wanna know why eggs pop in the microwave. And how do you avoid it?
Regards

KG Marite

What do you think?
« Last Edit: 21/11/2011 01:01:01 by _system »


 

Offline CliffordK

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Why do eggs pop in the microwave?
« Reply #1 on: 21/11/2011 02:51:35 »
I think it has to do with uneven cooking of the egg in the microwave (inside-out), and creating steam pockets that do not easily escape, or are relieved.  The proteins in the egg may seal around these steam pockets creating a trapping force that can create mini-explosions.

The eggs can explode both inside and outside of the shell, so cracking it isn't enough.

I believe there is a microwave hard boiled egg cooker that you can purchase if you wish.

If you wish to cook a hard boiled egg without the special cooker, it is possible, BUT BE PREPARED TO CLEAN YOUR MICROWAVE IF SOMETHING GOES WRONG!! If you wish to cover, make sure you don't get a good seal, but rather leave some room for expansion.

What I've had best luck with is:
  • Always use eggs that are a couple of weeks old.  Over time the eggs will loose a little moisture.  Those eggs a few weeks old have a somewhat larger air pocket which will help with the expansion.
  • Use a pin or something to puncture the shell into the air pocket at the fat end of the egg.
  • Take a ½ or ¾ cup of water and bring it to a boil in the microwave.
  • Add your egg.  Water must cover the egg.  It should bubble out a bit from the air pocket you punctured.  Put it back into the microwave
  • If the egg floats, it is pretty old.  It may not be a sign of decay, but it probably isn't the best boiling egg.
  • In my microwave it will take about a minute or so to get it cooked. 
  • Sometimes I can cook straight-through for a minute.  However I generally find it best to cook for 20 seconds or so, let it set for a few seconds seconds, perhaps gently stir after it has set for a few seconds, and repeat.  A low heat temperature setting may effectively do the same thing.
  • Keep in mind that portions of the egg could be "ready" to explode, so sometimes touching it can set it off.  Thus, it is always best to wait a few seconds before stirring or handling.
 

Offline RD

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Why do eggs pop in the microwave?
« Reply #2 on: 21/11/2011 12:15:05 »
BUT BE PREPARED TO CLEAN YOUR MICROWAVE IF SOMETHING GOES WRONG!!

and have the number of your local hospital handy ... http://www.guardian.co.uk/football/2009/may/15/kirk-broadfoot-egg-explosion-rangers
 

Offline Don_1

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Why do eggs pop in the microwave?
« Reply #3 on: 21/11/2011 17:31:52 »
BUT BE PREPARED TO CLEAN YOUR MICROWAVE IF SOMETHING GOES WRONG!!

and have the number of your local hospital handy ... http://www.guardian.co.uk/football/2009/may/15/kirk-broadfoot-egg-explosion-rangers

Now that's what I call getting egg on your face!
 

Offline Geezer

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Why do eggs pop in the microwave?
« Reply #4 on: 21/11/2011 18:49:42 »
What happens if you boil them in a pressure cooker? Does the increased pressure stop them exploding? Would a four minute egg be done in one minute?
 

Offline CliffordK

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Why do eggs pop in the microwave?
« Reply #5 on: 21/11/2011 19:38:07 »
BUT BE PREPARED TO CLEAN YOUR MICROWAVE IF SOMETHING GOES WRONG!!

and have the number of your local hospital handy ... http://www.guardian.co.uk/football/2009/may/15/kirk-broadfoot-egg-explosion-rangers

Now that's what I call getting egg on your face!
Oh...
Did I forget to mention Safety Glasses or Goggles?

Your internal pressure should dissipate within a few seconds.  However, if the problem is STEAM...  then the issue is that boiling an egg in boiling water on the stove...  you don't get the egg above the boiling point of water, and thus no steam pockets. 

In the microwave, you can get localized areas with temperatures above the BP of water, and thus internal explosive steam pressure.

Once the egg cools to below the BP of water...  or the temperature homogenizes to below the BP of water, then it is no longer explosive.  Since I microwave the egg in water, the temp will rapidly decrease to below the BP of water where it is safe.
« Last Edit: 21/11/2011 19:52:06 by CliffordK »
 

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Why do eggs pop in the microwave?
« Reply #5 on: 21/11/2011 19:38:07 »

 

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