How to hard boil and soft boil eggs perfectly (without turning the yolk green)

by Marge Perry on July 31, 2011

The other day, a student in one of my ICE (Institute of Culinary Education) classes asked me how long it takes to cook a soft-boiled egg. Actually, she may have said it correctly and asked for how long she should soft-cook an egg.

It is an important distinction. You don’t want to actually boil an egg– regardless of whether you want it soft, medium or hard. Unless, that is, you are having a Dr. Seuss party and want to make green eggs. Boiling eggs or cooking them for too long  turns the surface of the yolk green, thanks to a reaction between the sulfur in the white and the iron in the yolk.

The method for cooking eggs soft, medium or hard is the same; only the time changes. But before I describe the method, I want to tell you about the draw-backs to a couple of common methods.

Egg Cooking Don’ts

* Don’t bring water to a boil before adding eggs: placing an egg in boiling water changes the temperature of the egg too quickly and can result in cracked, leaking shells.

* Don’t boil eggs: As discussed above, this can lead to green-rimmed yolks. Vigorous boiling can also cause the shells to crack and the eggs to leak.

To choose how long you want your egg cooked, see the pictures below the recipe.

“Cooking time” below refers to the amount of time the egg sits in the covered pot.

Soft-boiled Egg

Cooked 3 minutes

Yolk is a thick liquid; white is mostly solid with some soft areas near the center

Soft Boiled Egg (3 minutes)

Medium-boiled egg

Cooked 12 minutes

This is my “hard-boiled egg” of choice. The white is firm; the yolk is firm but not dry. Note the slightly darker areas of the yolk: it is not wet, but it is not completely dry, either.

Lightly hard-boiled egg (12 minutes): Firm but not dry

Hard-boiled egg

Cooked 15 minutes

No moisture in the yolk; slightly dusty quality. White is firm throughout, again with no sign of moisture– but not rubbery.

Hard-boiled egg (15-minutes): firm and dry throughout

{ 13 comments… read them below or add one }

Leave a Comment

Previous post:

Next post: