Hard egg with shell in microwave. The cientific method

QUESTION . When you try to make an egg with a microwave without removing the shell, the most common is that the egg bursts and makes a mess messing up the whole egg oven duror crumbled and broken shell. Why does it burst in the microwave, and instead, does it burst when we boil it with boiling water?

FACTS . An egg is not a totally watertight object. There are pores in the shell that allow the exchange of gases between the inside and the outside. When heating an egg, the following phenomena occur:
a) The interior liquids are intended to expand and occupy more space.
b) The shell dilates, but not as much as liquids would.
c) The gases in the upper part of the egg increase its pressure.
d) The increase in pressure generated by all of the above causes the gases to exit partly through the pores, allowing the expansion of the liquids.
e) When the coagulation temperature of the clear and yolk proteins reaches approximately 65ºC, there should also be small changes in density, of which I do not know the magnitude.
f) When inside the egg reaches temperatures somewhat higher than 100 ° C, part of the water of the egg white and the yolk will vaporize, and this steam will have to leave the egg through the shell.

HYPOTHESIS . Since the microwave heats up faster than boiling water, the speed of steam generation inside the egg will be higher with the microwave. The pores of the shell will not let so much water vapor flow as the one generated inside, increase the internal pressure of the egg and finally burst.

PREDICTION . If we use a microwave with the possibility of regulating the heating, and we program a minimum power and a long time, it will cook the egg as if it were in a water bath, and it will not explode.

EXPERIMENT . I put a raw egg with a shell, of medium size (class M, between 53 and 63 g) in a dish, under a glass in case it explodes, and I put it to cook in the microwave in the P-20 position (a 20 % of the full power of 900 W), for eight minutes. Every two minutes I check the surface temperature of the egg to touch. I stop the experiment two minutes after condensed water has appeared on the inside surface of the glass vessel that covers the egg. At that time a small fissure had appeared in the shell, which also happens with eggs made with boiling water. The egg is easily peeled and fully cooked inside.

CONCLUSION . The hypothesis has been verified. You can cook an egg with the microwave provided it is done at low power and with long times.

BUT ... at the moment of splitting the egg with a knife, the egg bursts! The phenomenon is more complex than the previous explanation. By coagulating the white and the yolk, the white one acts as an impermeable membrane that does not let the water vapor that forms in the yolk escape. Probably the explosions of whole eggs in microwaves are due to both causes: the rupture of the shells by the internal pressure, and mainly the increase of pressure inside the yolk. The texture of the cooked yolk has become grainy, which is indicative of too long cooking time.

RECOMMENDATIONS . If you want to make a hard egg with the microwave, you have to remove the shell, beat the egg and put it in a glass, or in a silicone utensil like the recently Lékué company has patented to make cubic eggs, but without peel. They have nothing to do with the genuine cubic eggs explained a while ago.

Peel a hard-boiled egg without breaking it? Stop wasting time thanks to these tricks

Learning to boil an egg is a simple and easy feat to master
In the process they are leaving small bites, but there are several tricks
Image: iStock
Learning to boil an egg is a fairly simple and easy process to master, but when it comes to peeling it ... It's another story. However, if you have ever encountered this problem, there is a great diversity of tricks to peel the hard eggs without breaking them.

Once you have mastered the cooking time to make hard boiled eggs, you must learn to peel them without breaking them. We have all seen ourselves in this situation at some point in our lives; There is nothing worse than to peel a hard egg and discover that in the process there are small bites remaining. It can become an extremely frustrating feat, but there are several tricks to peel without breaking the clear.

Put it in a glass of water
This is probably one of the most effective methods. It consists of introducing the egg into a glass of water and adding a small amount of water. Next, you just have to vigorously shake the glass for 20 seconds so that the shells break. Once you have done this, you will see that it will be easier to peel them.

One of the fastest and most effective ways to peel a hard-boiled egg without breaking the clear is to remove a small piece of shell at each end and then blow hard. The egg will shoot out, so it is important to place one of our hands on the bottom.

With a spoon
As with the previous trick, in this case we will also have to remove a small piece of shell at each end of the egg and then carefully insert a spoon between the egg white and the shell. The pressure of this metal tool will cause the shell to come off easily.

Roll with one hand
Another of the best tricks is to gently hit and roll the boiled egg with the palm of your hand on a cutting board or other hard surface. This blow and circular movement cause small cracks in the crust, which ultimately helps the shell membrane to easily peel off the egg white.

Under water
Once cooked and cold, you should hit the egg several times on a flat surface. Then, dip it in cold water and start peeling it, you will see how it is very easy to remove the peel.


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