Why does the eggshell crack when I hardboil an egg?

Question

Sometimes when I boil an egg, the shell cracks. Does that mean the egg is old? I know how to boil the perfect texture and color egg but lately the shell has been cracking. In the past, I've never had that problem. I didn't change the way I cook it.

When I boil eggs, I put them in the pot first, add the water, and bring it to a boil. Once it begins to boil, I turn the heat down and after 6 minutes, I shut the flame off, pour out the water and put cool water in the pot to prevent the egg from getting overdone. (By the way, it cracks while it is boiling, not when i put the cool water in it) The yolk comes out perfectly yellow and good texture. So I don't think it's so much that my heat is too high. It's gotta be something else. Oh yeah, not only does the shell crack, but sometimes the egg white sticks to the shell when I try to peel it. Why is that? I've made perfect eggs where that didn't happen but every once in a while it does.

No I am NOT overcooking them. If I was overcooking them, the yolk would be nasty grey/green. My yolks are always yellow!

Answer 1

The egg expands, as it heats, faster than the shell. To prevent the shell from cracking, Take a large safty pin and poke a small hole in the large end of the egg, piercing the shell.
Good luck
Hope

Answer 2

Q: Why do shells stick to hard-boiled eggs? How can I peel them easily?

A: We've seen a lot of questions recently about hard-boiled eggs. For some, the problem is the shells sticking, others want to know how to prevent that "green halo" from forming around the yolk. Fear not, if you cook your hard-boiled eggs properly the yolks will be a beautiful yellow and the shells will slip right off.

First, let's address the issue of eggs sticking to shells. To prevent this, use eggs that are a week to 10 days old. Older eggs have a different pH from new eggs, which researchers say affects peeling. We also find that cooling eggs immediately after cooking in an ice bath makes them easier to peel.

But really, what good is an easy-to-peel egg if it is going to have that ugly green center? The green is made by the iron in the yolk combining with the sulfur in the white. Heat is a big foe of this chemical reaction. The longer you cook eggs, the more likely you are to end up with that green ring. The trick is to cook eggs just until the yolk is set without overcooking them. Removing the eggs from the hot water to an ice bath immediately after cooking will also help prevent the green from forming.

The best way to make easy-to-peel hard-boiled eggs with pure yellow centers is to place the eggs in a pot of cold water and add a teaspoon of salt. Place the pot on the stove and bring to a boil. Cover the pot and remove from heat and let sit for 13 minutes. Drain the eggs and immediately place in an ice bath until completely cooled. Drain and enjoy your perfectly cooked hard-boiled eggs.

–Food Network Kitchens

Answer 3

Hi, I boil eggs a bit differently and I get real good results but to answer your question about the cracking. If the eggs are cold when you add them to the water( according to my method) they do crack, but not all. Some shells have weak spots in them and you can see air bubbles comeing out of the cracks when the water gets hot. Now if youv'e ever had a "rotten" egg, its not rotten. Its an egg that a hen sat on anf it just began to turn into the begining stages of a chick, however small it may be, and the egg wont cook right.
The crack issue is because of the temp of the egg/water and the integrity of the shell as well.
Hope this helps. Regards, Ammoconfidential

Answer 4

I'm not sure why they crack, but I know a trick to stop them from being ruined if they do (which means it doesn't matter if they crack):
It sounds random, but put a match in the water before adding the eggs! I think it's something to do with what the tip is made of, but it stops the egg white from running into the water. I have also tried the vinegar technique but once or twice I found that it flavoured the egg!

Answer 5

Put cold eggs in cold water. Turn heat to medium and let the water *just* start to boil. Then turn off the heat, cover the pot, and walk away for 10 minutes. They are cracking due to the temperature extremes.

Answer 6

I think that might mean the water is boiling too much. Try adding a pinch of salt, or turning down the heat a bit when you put the egg in.

Answer 7

If you put the eggs in the pan with cool water to start, the eggs have a chance to change temperature without bursting as they come to a boil.
**To find out if an egg is old you try to float it in cool water. As an egg ages, an air pocket forms in one end as it loses moisture (ever boiled and egg and had a divot on one end?, That's an older egg) The air pocket makes the egg stand up on one end in a glass of water.
**To keep the yolks from turning muddy green, cool the eggs promply in a bowl of ice water, otherwise the yolks turn muddy green as they cool over a long period of time.

Answer 8

you're bringing to boil over too high heat. also, when peeling eggs hit the top of the egg on counter and the bottom slightly harder. this releases the egg from the shell all the way around. it's the "science" behind that fancy egg peeling thing on tv

Answer 9

Start off the eggs in cold water and put salt in it, bring to a boil, turn off, and cover until cooked.

Answer 10

Not sure, but I shake a little salt into the water, put the eggs into the cold water, and that seems to avoid cracking.