What Makes an Egg Grade A?

Everything you need to know about how eggs are graded
This article was posted by ewitek@getcrac… on June 26th, 2020

What are Grade A eggs in Canada and what makes them so special? First and foremost, “Grade A” in the egg industry is synonymous with “of the highest quality” or “top-notch” and “safe for consumers”. The carton of Grade A eggs you buy at the grocery store certifies that you’ll be going home with a safe, high-quality product.


Egg Carton with Canada Grade A logo


The magic happens at the grading station. In Ontario, after the hens lay the eggs, the farmer packs them into trays (called flats) and sends them to a grader. Thanks to the hard work of our Ontario egg farmers and the on-farm food safety programs they follow, most eggs are certified as “Grade A.”

Once at the grading station, the eggs go through a number of processes to ensure they are high-quality and safe for you and your family to eat – this is a process that the grader does not take lightly.  


eggs going through washing


The very first step of egg grading is the washing process. All eggs in Canada must be washed according to Canadian Food Inspection Agency (CFIA) food safety standards. The eggs are gently placed onto a continuously rolling conveyor belt that then moves the eggs through the washing process. This includes a series of water nozzles, brushes and food-grade detergent water. The eggs are rinsed with warm water before they are dried with large commercial dryer systems (basically like large hair dryers!). It is important that the eggs are dried thoroughly so they do not stick to the fibre material cartons.

Candling is the next stage where the largest part of the inspection occurs. In a darkened area, a light is shone under the egg allowing the inspector to have a look at what’s going on inside the shell.


egg candling


So, what is a grader looking for when deciding whether an egg makes the cut to be “Grade A”?

1) Cracked Shells

Before all else, it’s important to examine the shell. Are there any hairline cracks? Some of these would only be revealed through a close inspection during the candling process. When examining an egg in your hand, you probably wouldn’t notice one of these fractures at all because the tiny cracks can be invisible to the naked eye. Remember, eggs are laid in barns where they might come into contact with manure, dirt or other substances that you’d never want to enter the egg. The shell is meant to protect the egg from contamination, so it’s critical to check whether the shell has been compromised in any way.

2) The yolk 

When a grader is examining the yolk, they are looking for it to be nice and centered within the egg. Each yolk is suspended in the egg white by two little white spring-like membranous strands – these are called the chalazae (kuh-lay-zah). Over time, they uncoil and become looser, making the yolk less centered in the egg. It’s an indication of freshness to have a well -centered egg and that’s why it’s important in the grading process!

3) The air sac

Have you ever noticed a little pouch of air at the bottom of the wide end of the egg? It occurs as a result of the egg cooling after it’s been laid. The more time that passes, the bigger this air cell gets. Graders will examine the size of the air sac (the smaller the better) to ensure that the egg is indeed, very fresh.

4) Internal spots

Sometimes when a hen lays her egg there can be a tiny piece of pink tissue (meat spot) or a small vein (blood spot) that attaches to the yolk. Blood spots are caused by the rupture of a blood vessel in the hen when the egg is forming. Meat spots are protein material suspended in the egg. Even though there is no obvious food safety concern here, these eggs look rather unappetizing for humans and do not make the “Grade A” cut!


eggs being categorized by weight


The next stage in the grading process is weighing every egg and dividing them into size categories including peewee, small, medium, large, extra large and jumbo. For example a large size egg has a weight of anywhere between 56.00 to 62.99 grams. After the eggs have been divided into size categories they are then carefully packaged into a properly labelled carton with a best before date. These cartons of eggs are then shipped across the province to local grocery stores near you!

What happens to eggs that don’t make Grade A?

Before answering this question, it’s important to note that there is absolutely nothing wrong with Grade B and C eggs – they’re still just as tasty and go through the same safety protocols and inspections. However, we like you to get the crème de la crème when it comes to fresh, good looking eggs at the grocery store. So we save the Grade A eggs for you to take home and crack open which is approximately 95% of all Canadian eggs. As for the small percentage of Grade B and C eggs - we certainly still make sure that they get used!

What are Grade B eggs?

These eggs have a shell that’s fully in tact but may be slightly stained, misshapen or might not be the smooth texture typically found on Grade A eggs at the grocery store. Internally, their whites may not be as firm as a Grade A egg and their yolk might not be perfectly round (it may have flattened a bit). Essentially these Grade B eggs are just not as pretty as the Grade A eggs found at the grocery store. Grade B eggs are sent to a facility called a ‘breaker’ that carefully collects the perfectly good liquid from inside each egg, pasteurizes the liquid and sells it to the baking industry to be used in baked goods and various shelf stable products (such as liquid egg in cartons, mayonnaise, salad dressings or dried/powdered egg).

What are Grade C eggs?

Grade C eggs have a mildly cracked shell and would go through a similar process as the Grade B eggs. However, the pasteurizing step is extremely important with Grade C eggs to ensure that any possible bacteria that may have entered the egg through the small crack is destroyed before continuing to the processing step.

So there you have it! Now when you go to the store and purchase Canadian Grade A eggs you’ll be an expert on why they’re the best quality eggs. Important to note is that these grading techniques are not the only thing that makes Canadian eggs a very high-quality product.