How to Hardboil an Egg

Several techniques make it possible to hardboil eggs without cracking the shells.
Several techniques make it possible to hardboil eggs without cracking the shells.
2007 R/F cd2


Q. How do you keep eggs from cracking when hardboiling?

A. There are a couple things to try that may prevent cracked eggs, according to Shirley O. Corriher, author of Cookwise: The Hows and Whys of Successful Cooking (HarperCollins, 1997). Eggs crack because gases within the egg expand as they are heated, and they attempt to escape through the porous egg shell.

Changing the egg's temperature by quickly bringing cold, refrigerated eggs to a boil forces the gases to expand too rapidly, breaking through the shell and causing cracks. To slow down that process, Corriher, a chemist and food stylist, suggests bringing eggs to room temperature before cooking.


You could also let the eggs soak in hot tap water for four or five minutes before cooking. This minimizes the difference in temperatures between the eggs and the cooking water and causes the gases to escape more slowly.

Corriher suggests letting eggs stand in hot water for four minutes; drain, add more hot water and let stand four minutes more. Lower eggs into boiling water and immediately reduce heat to a very low simmer. Simmer, uncovered, about 15 minutes. Rinse under cold water.

To cook cold eggs in cold water, Corriher suggests placing eggs in a saucepan large enough to hold them in one layer. Cover with 1-1/2 inches cold tap water and bring to a boil. Turn heat to low, cover, and cook 30 seconds. Remove from heat and let eggs stand in cooking water for 15 minutes. Rinse under cold water.

Other tips: Eggs close to their expiration date are more likely to crack, because eggshells become less permeable as they age. Use fresh eggs for hard cooking whenever possible. Also, "hardboiling" is a misnomer: Eggs should be cooked at a low simmer, not boiled.

Q. What can I do to make sure I'm safely using eggs in cooking?

A. By now, everyone is aware of the dangers of salmonella, a bacteria that causes a type of food poisoning. Although only a very small percentage of eggs are contaminated with salmonella, it is important to handle all eggs safely when cooking.

  • Keep eggs refrigerated. If a recipe calls for room temperature eggs, remove only the number of eggs needed and let them stand on the counter for 30 minutes before using. Also, buy eggs only from stores that keep them refrigerated.
  • Do not eat raw eggs. Avoid lightly cooked eggs. Whites should be set and yolks should be thickened. A temperature of 160 degreesF kills salmonella.
  • After handling raw eggs, wash your hands before touching other food or equipment. Keep equipment and counter surfaces clean.

For more information on cooking with eggs, see: