The Effects of Boiling

When you boil a raw egg in water, heat causes the proteins in both the yolk and the white to start moving around at a high speed until they eventually split apart. It is this porosity that enables a raw egg to be boiled in its shell, as the 7,000 tiny holes allow the transfer of the cooking water in and out. As the proteins reorganize themselves, the egg white turns its characteristic opaque white color while the yolk firms up but still maintains a gelatinous texture. The longer you boil a whole raw egg, the more the water evaporates from the yolk, until it reaches a point where it has a thick, dry, pasty consistency.

Boiling in the Shell

The process of boiling a raw egg in its shell produces different results depending upon how long you cook it. A traditional soft-boiled egg, which appears on many breakfast tables, is the result of boiling the egg for five to seven minutes, then removing it immediately from the pan. You can remove the entire shell before eating or break off just one end of the shell and eat from it in a special egg cup designed for that purpose that keeps the shell upright. For hard-boiled eggs, allow 12 to 15 minutes of cooking time, remove the eggs from the boiling water and plunge them into cold water to stop the cooking process. This helps to prevent darkening of the yolk.

Poaching Eggs

Poaching means boiling an egg out of its shell and cooking it just until the white is set and the yolk still liquid and runny. You can do this in an ordinary saucepan by bringing about 2 inches of water to a boil and gently sliding the raw eggs in. The eggs will start cooking immediately, and if they're fresh, the whites will maintain a uniform shape. Poach the eggs for two to four minutes, depending upon how runny you like the yolk. You can also poach eggs in a special pan that has individual cups, but the eggs don't touch the water, so it's not strictly poaching.

Why Cook Eggs

Raw eggs can contain many different types of bacteria which can be destroyed by boiling, as the temperature at which water comes to a full boil is 212 degrees Fahrenheit, which is hot enough to destroy disease-causing organisms like salmonella. If the whites and yolks of your boiled eggs are firm, they are safe to eat. In a dish that contains eggs, the American Egg Board advises that the dish is safe once it has reached an internal temperature of at least 160 degrees F. If you want to eat eggs that are runny but you are worried about the health risks, buy pasteurized eggs.