How can you tell the difference between a good egg and a bad egg? Eggs are rated and graded into three classifications determined by the United States Department of Agriculture (USDA). If you have chickens and plan on selling eggs, grading and sizing is required. As a general rule, you should grade all your eggs before you store, sell or consume them.
When grading eggs, both the interior and exterior quality is measured. This process does not take into account weight or shell color. According to USDA guidelines, eggs are graded and labeled as AA, A, and B. U.S. Grade AA eggs are nearly perfect. The whites are thick and firm and the yolks are free from any defects. The shells are clean and without cracks. U.S. Grade A eggs appear to be the same as Grade AA, but the difference between grade A and grade AA eggs is a slightly lower interior quality. U.S. Grade B eggs are noticeably different. They may have slight stains and be irregular in shape and size. The quality of the interior is further reduced. Grade B eggs are not sold in supermarkets, but are used commercially in powdered egg products or liquid eggs.
Begin the egg grading process by checking the quality of the shell. The ideal eggshell is clean, smooth and oval in shape with one end slightly bigger than the other. Eggs with cracked or broken shells should be discarded. If you are selling the eggs, remove any with unusual shapes, textures or thin spots on the shell. While they are edible, they break easily and will be unacceptable because of their appearance.
Grading the interior of the egg is performed by a method called candling. Using an egg candler will allow you to examine the air cell, the egg white (called albumen) and the yolk. Candling also lets you check for spots and cracks. Listed below are the different components to observe when candling an egg:
Air Cell Depth - The air cell is the empty space between the shell and the white usually found at the bigger end of the egg. As the egg ages, the air cell depth grows and the quality of the egg diminishes.
White or Albumen - The white of the egg is called the albumen. The quality is based on its clarity and thickness. Look for a clear color without discolorations or floating foreign matter. Thick albumen allows limited movement of the yolk and indicates a higher quality egg.
Yolk - The quality of the yolk is determined by the distinctness of its outline and other features like size, shape and absence of any blemishes or blood spots. It should be surrounded by a dense layer of albumen.
Spots - Candling can help reveal foreign matter like blood spots or meat spots. Eggs with interior spots should not be sold.
USDA Grade Standard Chart: You can use the USDA Grade Standard Chart as a quick reference for determining the grade of an egg by candling. (From the article: Proper Handling of Eggs: From Hen to Consumption by the Virginia Cooperative Extension)
If you plan on selling your eggs, you need to sort and size them. Large and extra large eggs are the best sellers. You might be surprised to learn that eggs are not sized individually, but rather sized by the combined weight of one dozen eggs. A size breakdown by weight can be found in the chart below.
While there are a few things to learn about grading and sizing eggs, the process isn’t too difficult. You can master the technique quickly with just a little bit of practice and the right tools. From there, all you would need to do is make sure that you have all the materials you need to get your eggs out to the market. EggCartons.com makes it easy to find all your egg trays, printed and blank egg cartons, and egg shipping boxes.
For more information about grading and sizing eggs, you can refer to the American Egg Board.
Egg Grading FAQs
What Is Egg Grading and Why Is It Important?
Egg grading is the process of sorting and grading by size, shape and the interior and exterior quality of the eggs. It is important because it enables people to easily determine the quality of the eggs.
What Does a Grade A Egg Mean?
A Grade A egg is typically what is found in most grocery stores. Grade A eggs are clean and unbroken in a normal shape with an air cell measuring no larger than 3/16 of an inch deep. The whites of a Grade A eggs will be clear and reasonably firm with no blood spots. A Grade A egg will be nearly free of any obvious defects.
What Is the Difference Between Grade A and Grade AA Eggs?
Grade A and Grade AA are the most common egg grades found in supermarkets. Both grade A and grade AA eggs are near perfect eggs with clean unbroken shells appearing normal in shape. Egg Grade AA is the highest grade and egg can receive which illustrates its impeccable interior and exterior quality. Grade AA eggs will have an air cell measuring no larger than 1/8" whereas Grade A eggs may have an air cells as large as 3/16". Also, Grade AA eggs will have whites that are clear and firm allowing the yolk to only be slightly defined when passed in front of light, while a Grade A egg will have whites that are only slightly firm and the yolk is fairly well defined.