Now shake the pan back and forth, causing the eggs to crack against the side. Cool with cold water and peel. To determine whether and egg is fresh without breaking the shell, immerse the egg in a pan of cool salted water. If it sinks to the bottom, it is fresh. If it rises to the surface, throw it away.
Fresh eggs are rough and chalky in appearance.
Old eggs are smooth and shiny. To determine whether an egg is hard-boiled, spin it. If it spins round and round, it is hard-boiled. If it wobbles and will not spin, it is raw. Pierce the end of an egg with a pin, and it will not break when place in boiling water.