To ensure consistent egg quality standards, eggs are graded based on both external and internal conditions.
External Grading Factors
Even eggs are more than just appearance. So, how are they graded? Why not just call them "white" or "white blemish"? There are many factors involved!
Shell Shape and Texture:
The primary characteristic of a high-quality egg is an oval shape, narrow at the top and wide at the bottom, without any rough spots or cracks.
Shell Cleanliness:
The cleanliness of an eggshell significantly impacts its grading. An egg with noticeably dirty shells and visible stains is automatically excluded from grading.
Eggs with minor ridges or stains are still eligible for grading, as long as the stain is not concentrated in one area and covers less than one-sixteenth of the shell surface.
Clean eggs are free of any foreign matter, deformities, or stains. Minor marks, stains, or traces of processing oils are permitted, as long as they are not visible to the naked eye.
Internal Grading Factors
Grading eggs based on their internal quality without cracking them might seem unrealistic. As technology advances, the egg-lamp method has replaced flames with flashy LED lights, but the principle remains the same, ensuring a consistent grading process.
Air Cell:
Freshly laid eggs contain a small amount of air. As the egg cools, the liquid components contract, forming an air cell inside the egg. While the air cell is the final factor in egg grading, it still counts; the larger the air cell, the lower the grade.
Eggshell Whiteness:
The outer layer surrounding the yolk, called the albumen, determines the whiteness of the eggshell.
Yolk Quality:
During the candling process, graders assess the quality of the yolk by examining its shade and vibrant color. Grade AA eggs have a pale white yolk with a vibrant color; Grade A eggs have a greenish yolk with a lighter yolk; and Grade B eggs have a very dark yolk with a dull yolk.
After grading, eggs are sorted by weight using an egg sorting machine. It's important to note that the weight of an egg doesn't determine its quality or taste; it's primarily for uniform packaging.
