A fresh egg feels heavy while an older egg feels light in weight because it has more air inside. Test the egg and find out if the egg is rotten before you cook it.
Step 1: Fill bowl Do the float test: put the egg in a deep bowl of water. If it sinks straight to the bottom, it's fresh. If it floats, it means it's old, but may still be safe to eat. Proceed to the crack test.
Step 2: Put egg in bowl Crack a floater into a bowl and give it a sniff: if it gives off an unpleasant odor, throw it out.
Step 3: Watch the egg No odor? Examine the egg white: a pink or iridescent appearance means it's spoiled. Don't worry about red spots -- they represent blood vessel ruptures that occurred at the time of ovulation and have nothing to do with safety or freshness.
TIP: A cloudy egg white means the egg is very fresh; a clear egg white means the egg is aging.
Step 4: Crack egg Disregard the color of the yolk -- it varies in accordance with the hen's diet. And a green ring on a hard-cooked yolk simply means you overcooked it.
FACT: When a hard-boiled egg is difficult to peel, it means it's very fresh.