Re: Why are some hard-boiled eggs easier to peel than others?

The American Egg Board feels the biggest single factor is the freshness of 
the egg involved. See: http://www.aeb.org/faq/general-faq.html#peel.

Here are some pointers to make eggs which peel easily:

1. Use eggs which are at least 10 days old. Older eggs have membranes next 
to the shell which start degrading, bonding them less tightly to the 
shell. This is a phenomenom similar to "aging" of meat to make it more 
tender.

2. Start the eggs in cold water and bring to a boil. This prevents the 
shells from being shocked with heat.

3. After cooking, shock the eggs with cold water to assist in peeling ease.

4. Store eggs with pointy-end upright to maintain the airspace at the top.