Boiling eggs may sound like the simplest thing you could possibly cook, but if you’ve ever boiled an egg you’ve probably run into problems at one time or another. The challenges with boiling an egg generally fall into two categories: cooking the egg, and peeling the egg. Despite following a set of directions precisely you might have found your eggs under/over cooked, or perhaps when you tried to peel the egg it ended up looking like the surface of the moon.
The good news, is that both of these problems are easily resolved with a little understanding behind the science of eggs. Read on and you’ll be boiling perfect oval eggs whether you prefer them hard-boiled or soft in the center.
The first thing you have to understand is that the egg yolk sets at a much lower temperature than the egg white (70 degrees C vs 80 degrees C). Since the heat source (boiling water) is outside the egg, the egg cooks from the outside in. In theory this means that by the time yolk is set, the white has also reached it’s higher setting temperature.
The problem is that since the boiling water is significantly hotter than the setting temperature of the egg, it’s very easy to zoom past the desired temperature. Because the temperature is rising so fast, it’s difficult to pinpoint exactly when to stop the cooking to get the egg exactly how you like it. The problem with most boiled egg instructions is that they create a formula (put eggs in cold water, bring to boil, boil for X minutes) assuming you put the exact same size and temperature of egg into the same amount of water in a the same pan on the same stove… Well you get the idea.
But you can get a much better control over the cooking just by adopting a different approach.
Put refrigerated eggs in a heavy bottomed pot and cover with cold tap water so they’re covered by about 1″ (2.5cm) of water. Bring the water to a full boil (100 degrees C) over high heat, and then remove the pot from the heat. Let the eggs cook the rest of the way using the residual heat in the water. As the temperature of the egg rises, the temperature of the water will fall, which will give you a much wider window when your egg is perfectly cooked.
For how long though? Well, there a number of factors that need to be taken into consideration, but let’s assume large eggs, out of the fridge, being cooked at sea level (or at least, not at the top of a mountain), 4 eggs to a suitable pot.
2 minutes – The white isn’t fully set and the yolk is totally raw
4 minutes – The white is fully set, but the yolk is thick and runny
6 minutes – The white is fully set, and the yolk is mostly set, but still a little runny in the middle
8 minutes – The white is fully set, and the yolk is set, but tender
10 minutes – The white is fully set, and the yolk is fully set
Remember to transfer your eggs to cold water as soon as you take them out of the pot to stop the cooking immediately. Otherwise, your eggs will continue cooking even after you’ve taken them out of the water.