The eggs we buy in the grocery store are graded either AA, A, or B. What's up with that?

Image zoom

It's Not About Size...

Eggs are sized from Jumbo (about 2.5 oz per egg) down to Medium (about 1.7 oz per egg). But an egg of any size can be any grade.

It's Not About Color...

Brown and white eggs are graded the same way.

It's Not About Flavor...

All grades taste the same.

So…???

"It's more about appearance than anything," Serena Schaffner with the American Egg Board told me.

It's About How The Shell Looks...

Grade AA egg shells are completely clean, thick, smooth, and have a definite oval shape. With Grade B eggs, the shell may have a bit of a stain or bumps on it. Eggs are very much judged by their covers.

And How Firm The White Is…

The firmer the egg white, the higher grade the egg is going to get.

Um, Wait A Second. How Is The Egg White Inspected Without Breaking The Egg?

It's all about an old-time technique called egg candling. You hold the egg up to a bright light in a dark room. If the yolk has a distinct outline, you know it's also firm. Once farmers used a candle, but now folks use an electronic egg candler (Yes, you may buy one on Amazon.), or even just use the flashlight function on their smartphones.

Although Sometimes They Do Break The Egg.

Sometimes an inspector will break a sample egg and—in what must really be a moment to tell the kids about when she gets home—uses a "tripod micrometer" to measure the height of the egg white. Here's what she's looking for:

Image zoom Egg Grades

Okay, Have We Covered Everything By Now?

Of course not! The USDA has a 50-page manual on egg grading. Click here if you want to check out the pdf. But the basic facts are these: Buy Grade AA eggs if you plan to put them in an art show, but if you're gonna crack and cook 'em, Grade B will do just fine.