Why do eggs stick to shells?

Eggs stick to their shells primarily due to the presence of a thin protective coating called the cuticle, which can create adhesion between the egg white and the inner shell membrane. Additionally, the proteins in the egg white can also interact with the shell, especially when the egg is fresh. As eggs age, the pH of the egg white rises, causing the proteins to denature and making them less adhesive. This is why older eggs are often easier to peel after boiling.