Boiling eggs appears simple, but anybody who has peeled a hard-boiled egg and discovered a peculiar green ring around the yolk knows it is not always so. While the egg is still edible, the green ring is commonly regarded as a symptom of overcooking, which many people find unappealing. So, how long should you boil eggs to achieve the right result? And how do you avoid that unappealing discoloration? Let us break it down.
The answer depends on whether you prefer soft, medium, or hard yolks. Here is a basic guide to boiling huge eggs: Soft-boiled eggs (with somewhat runny yolk): 6-7 minutes. Medium-boiled eggs (jammy yolk) take 8-9 minutes. Hard-boiled eggs (completely cooked yolk): 10-12 minutes. Begin with eggs in a saucepan filled with cold water. Bring the water to a boil over medium high heat. When it reaches a boil, turn off the heat (or lower to a medium simmer), cover the pot, and begin timing.
What causes the green ring around the yolk? The greenish-gray ring is formed by a chemical reaction between sulfur and iron in the egg. When eggs are cooked for too long or at too high a temperature, the sulfur in the egg white combines with the iron in the yolk, resulting in ferrous sulfide, which turns green. It’s absolutely nontoxic and has little effect on flavor, but it can be visually unpleasant, particularly when making deviled eggs or salads. Do not overcook the eggs.
Stick to the stated cooking time: 10-12 minutes is sufficient for hard-boiled eggs. Overcooking for more than 13-14 minutes raises the chance of discolouration. Cool the eggs rapidly. When the time is up, place the eggs in a bowl of ice water or run them under cold water for a few minutes. This slows the cooking process and helps to keep the green ring from forming. Use fresh but not very fresh eggs.
Extremely fresh eggs can be more difficult to peel, but eggs that are too old may contain air pockets that interfere with cooking. For the greatest results, use eggs that are about a week old. Avoid a quick rolling boil. Excessive agitation might cause cracks in the shells and uneven temperature increases. A slow boil, or even steeping in hot water after boiling, is more efficient.
