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Quality & Grades of Eggs


All eggs sold at grocery stores must meet strict standards. Only those of high quality reach the consumer. Eggs must be checked for interior quality by candling, a process where eggs are passed over a strong light to show the shell and interior.

Changes in Quality Over Time

Eggs must be stored in the refrigerator to maintain Grade A quality. Eggs kept at room temperature deteriorate as much in a day as they do in a week under refrigeration.

As an egg ages:

  • The AIR CELL becomes larger
  • The YOLK becomes flatter, larger and breaks more easily
  • The THICK WHITE becomes thin and watery

Egg Grades

Grade A

Eggs sold at grocery stores in Alberta are primarily Grade A eggs.When examined at the grading station, Grade A eggs must meet the following requirements:

  • Thick white
  • Round, well centered yolk
  • Small air cell (less than 5 mm deep)
  • Clean, uncracked shell with normal shape

Look for this symbol on egg cartons as your guarantee of top quality.

Canada Grade A Egg Weights

Jumbo  At least 70 grams
Extra Large
 At least 63 grams
Large  At least 56 grams
Medium  At least 49 grams
Small  At least 42 grams
Pee Wee
 Less than 42 grams

Grade B

  • These eggs are mostly used for commercial baking or go to hospitals, restaurants, etc. Very few are sold at retail stores.
  • Yolk is slightly flattened; white is thinner.
  • Shell is un-cracked and may have a rough texture; and/or be slightly soiled and stained.

Grade C

  • The lowest egg grade, these are used in the production of processed egg products only. They are not sold in grocery stores.
  • Yolk is flattened and may be oblong in shape; white is thin and watery.
  • Shell may be cracked and/or stained.

Common Egg Questions

Shell Colour

Shell colour may vary from white to brown, depending upon the breed of the hen. There is no difference in nutritive value, flavour or cooking performance between a white shelled and brown shelled egg.

Yolk Colour

Yolk colour reflects the type of grain in the hen's feed. A wheat-based diet yields a lemon yellow yolk colour. A corn or alfalfa-based diet yields an orange yellow yolk colour.

Egg White Colour

Sometimes a raw egg may have a greenish hue due to the presence of riboflavin (Vitamin B2). Sometimes the raw egg white may be cloudy. This is due to the natural presence of carbon dioxide which has not had time to escape through the shell and thus indicates a very fresh egg. In both cases, the egg is perfectly safe to eat.

Blood Spots

Blood or "meat" spots are occasionally found on an egg yolk. These tiny red or red-brown spots are not harmful. They are caused by the rupture of a blood vessel during formation of the egg. Blood spots do not indicate a fertilized egg. Candling reveals most blood spots and those eggs are removed, but even with electronic spotters, it is impossible to catch all of them. If desired, the spot can be removed with the tip of a clean knife prior to cooking. These eggs are safe to eat.

"White Ropey Things" (Chalaza)

More noticeable the fresher an egg is, the two chalaza in an egg "anchor" or keep the yolk in the centre of the egg. They are safe to eat and generally "disappear" when an egg is cooked. However, if desired, they can be removed before cooking with the tip of a fork or knife.