How Are Egg Sizes Determined?

by Suzanna Didier ; Updated September 28, 2017

You might not have solved the age-old question of which came first -- the chicken or the egg -- but if you’re like most Americans, that hasn’t stopped you from enjoying this high-quality protein. The U.S. Department of Agriculture reports that Americans ate an average of 247 eggs per person in 2008, up from 236 eggs per person roughly 20 years earlier. The USDA also sets the standards for egg size, quality and safe handling.

Size

Surprisingly, egg size is determined by weight, rather than the dimension of any one egg. The USDA’s standard for 1 dozen jumbo eggs is a minimum weight of 30 ounces. One dozen extra large eggs must weigh at least 27 ounces, twelve large eggs need to weigh in at 24 ounces, medium eggs must be 21 ounces and small eggs have to weigh 18 ounces. Should you run across a dozen “peewee” eggs, their weight needs to be at least 15 ounces.

Grading

The USDA doesn’t just provide consumers with the size of an egg -- they also supply egg grades for egg packers paying a fee. Those who opt out of the federal system are monitored by state agencies. USDA egg grades are either AA, A or B and indicate a wide array of qualities. According to the American Egg Board, grade AA eggs have yolks that are firm, round and high with reasonably thick whites that cover a moderate area when broken into a pan. Contrast this with grade B eggs that cover a wide area when broken and display somewhat flat and large yolks.

Egg Safety Rules

In response to consumer concern over egg safety issues like salmonella, Congress enacted the Egg Safety Rule (which went into effect in July 2010). It applies to producers with 50,000 or more laying hens, mandating they purchase chicks from flocks controlled for salmonella; control pests, rodents and other hazards; and meet testing, cleaning and refrigeration standards. These large egg producers must also register with the U.S. Food and Drug Administration and maintain records of their safety practices.

Egg Safety at Home

There are a few egg-handling guidelines that the USDA recommends that you follow to prevent egg-safety problems. Any area or item (e.g., utensils or equipment) that comes into contact with raw eggs should be washed with hot soapy water. Raw eggs used in cooking or baking should be cooked immediately to a minimum temperature of 160 degrees Fahrenheit, or refrigerated for up to 24 hours and then cooked. Dishes containing cooked eggs should be eaten within three to four days, and cook your eggs until both the white and the yolk are hard.

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About the Author

Suzanna Didier's work appears in online publications including the National Geographic website, SFGate and Local.com. She is an avid cook who lives on a hobby farm, direct-markets organic produce to local restaurants and has taught at the preschool, elementary and college levels. Didier holds a Master of Arts in education from the University of Oregon.