Listen up, cooks. You may not be a gourmet chef at some fancy restaurant, you may even have trouble deciding when to remove that steak from the charcoal, but at least you know how to hard-boil eggs: 10 minutes in boiling water. Right?
WRONG! Go to your room. Ten-minute eggs have whites like rubber and graying, dry, yucky yolks.
It turns out that time in the heat has nothing to with making a tasty, palate-pleasing egg. It's all about the temperature!
The contents of an egg are proteins and water (yolks have fat as well), and when you cook them those proteins uncurl into strands that, at some point, depending on the particular type of protein, bind together into a mesh that traps water droplets, keeping the eggs soft and tasty. The temperature alone determines when this happens for the egg's various proteins! You can cook the eggs over night, for Pete's sake, as long as the temperature remains correct.
For instance, cooking eggs in the oven at precisely 149F (for whatever time) will give you an egg with whites "as delicately set and smooth as custard, and the yolk is still orange and soft." Bake them at 153F, and the yolk has begun thickening up. Do it at 158 F, and the eggs have a rather firm yolk but still have tender whites. For still-firmer eggs, try cooking at 167F or 176F. But boiling at 212-degrees? Way too hot. Hence the rubbery whites and dry yolks!
This from writer Patricia Gadsby in an article called "Cooking for Eggheads" published in 2006 in Discover magazine. She interviewed a French scientist studying "molecular gastronomy," a discipline that studies the science of cooking food rather than the art of doing so. She says she sure liked the eggs.