1. It usually takes five minutes to boil cold water. In the process of cold water cooking, the solidification speed of eggs is relatively very slow, so eggs can't be cooked with boiling water. After the cold water is boiled, we need to cook for five minutes. At this time, the eggs are all cooked.

2. Of course, although half-cooked eggs have higher nutritional value, everyone has different tastes. Most people still accept hard-boiled eggs, so it is generally best to boil them for ten minutes, otherwise they will be too old. You get old in more than ten minutes. Such eggs not only taste bad, but also are not conducive to human digestion and absorption.