Do your eggs have a grade? Each USDA grade is a mark of the egg's quality. Grade AA eggs are the highest quality whereas Grade B are the lowest.
Egg graders determine quality based on the egg's: shell, white, yolk, and air cell. Here's how to tell a high quality egg from a low one.
The Shell. Ideally, you want a smooth, clean surface.
AA: Clean and unbroken.
A: Clean and unbroken.
B: Clean or slightly stained with an abnormal shape.
The Air Cell. When an egg is first laid it has hardly any air, so the freshest eggs have the smallest air cells.
AA: No more than 1/8 inch.
A: Between 1/8 to 3/16 inches.
B: Larger than 3/16 inches.
The Yolk. If you hold the egg in front of a bright light, you want a firm yolk that isn't very visible from the outside.
AA: Yolk is slightly defined.
A: Yolk outline is more defined.
B: Yolk outline is clearly defined.
The White. Ideally, you want a thick white that won't let the yolk move around much.
AA: Clear and thick.
A: Clear and reasonably thick.
B: May contain blood spots and is thin and watery.
While an egg's grade is a sign of quality, it's not necessarily a sign of safety. For example, egg graders don't check for salmonella.
Not all eggs come with a grade. But marketers can use the USDA shield to charge more for their eggs. Whether your eggs have a grade or not, they're still a delicious part of a balanced diet.