Q: When I boil eggs, the shells crack. How can I prevent this?

Here are a few things you might try in order to avoid having the shells crack when you boil eggs:

• Visually inspect the eggs before cooking.  If possible, avoid using eggs with fine surface lines that may crack during cooking.  Always discard eggs that are already cracked.
• Start the eggs off in cool water.  The sudden thermal shock of going from a cold refrigerator to  hot water may be enough to cause cracks to occur.
• Place the eggs gently into the pot.  Don't drop them in.  Hitting against the bottom of the pan can cause cracks .
• Cook the eggs just below a  simmer.  The agitation of eggs being tossed around in water at a rolling boil can cause cracks, too.

There is no strong evidence, according to Harold McGee (On Food and Cooking: The Science and Lore of the Kitchen), that piercing the end of the egg makes much of a difference to whether or not the shell cracks.

To learn how to peel the eggs once you have hard-boiled them, go to Peeling Hard-Boiled Eggs.

One final note.  I am a huge fan of the Norpro Egg Rite Egg Timer, or any of a number of similar products.  It is an oblong plastic item that you place into the pot with your eggs when you start cooking them.  About halfway inside is a scale with the lines marking 'Soft', 'Medium', 'Hard'.  As the eggs cook, the inside of the Egg Rite changes color, moving from the edge toward the center.  When the color change reaches the line showing the degree of doneness you are looking for, take the eggs off of the heat.  The Egg Rite lets you see what is going on inside the egg without having to crack it open!