Is a hard shelled egg fresh or long aged

Eggs that are difficult to shell are usually fresh. The freshness of eggs is related to the adhesion of the eggshell membrane. The eggshell membrane of fresh eggs is tightly attached to the protein, while eggs stored for a long time may experience membrane separation due to the escape of carbon dioxide. Fresh eggs have a lower pH value in the egg white, and the inner membrane of the eggshell has strong adhesion to the protein, making it difficult for the inner membrane to detach from the eggshell after cooking. After fresh eggs are cooked, there is often a phenomenon of protein sticking to the shell, which can easily lead to protein damage when peeling. During the storage process of eggs, the air chamber gradually expands, and the adhesion between the inner membrane of the eggshell and the protein weakens. After being cooked for a long time, the eggs are more likely to peel off completely. The freshness of eggs can be determined by a submergence test. Fresh eggs will sink flat to the bottom of the water, while eggs stored for a long time will tilt or stand upright.

Due to the aging of the inner membrane of the eggshell, the gap between the membrane and the eggshell increases during cooking, reducing the difficulty of peeling the shell. But after storing eggs for more than three weeks, the yolk may become loose or have a strange odor, and it is not recommended to consume them at this time. To determine the freshness of eggs, it is necessary to consider the production date, odor, and yolk condition. The ease of peeling is only an auxiliary reference indicator.

It is recommended to purchase eggs through legitimate channels and check the production date. When storing, keep them refrigerated and avoid contact with other odorous substances. Before cooking eggs, they can be left at room temperature to cool down and reduce cracking. Soaking them in cold water immediately after cooking can help peel the shells. Eggs should be consumed in moderation in daily diet, paired with vegetables and fruits to ensure a balanced nutrition.