Why Size Matters: Understanding Egg Grades and Sizes
Why Size Matters
When you're standing in the egg aisle at your local grocery store, the variety of egg sizes and grades can be overwhelming. You might wonder what these classifications mean and how they can affect your cooking experience. In this post, we'll delve into the differences between egg sizes and grades and provide you with the information you need to make the best choice for your next egg-based dish.
Egg Sizes: From Peewee to Jumbo
Eggs are categorized into six different sizes based on their weight, ranging from peewee to jumbo. Here's a quick breakdown of the different sizes and their respective weights according to the California Department of Food and Agriculture (CDFA):
Peewee: under 40.16 grams (1.41 ounces)
Small: 40.16-47.24 grams (1.41-1.66 ounces)
Medium: 47.25-54.33 grams (1.67-1.91 ounces)
Large: 54.34-61.41 grams (1.92-2.16 ounces)
Extra-Large: 61.42-68.50 grams (2.17-2.41 ounces)
Jumbo: over 68.51 grams (2.42 ounces)
Generally recipes call for large eggs, which are the most commonly found size in grocery stores. However, if you have access to different egg sizes, keep in mind that the size will affect the overall volume and consistency of your dish. You may need to adjust the number of eggs or the cooking time to compensate for size differences.
Egg Grades: AA, A, and B
In the United States, eggs are graded based on the quality of the shell, the egg white (albumen), the yolk, and the presence of any defects. The U.S. Department of Agriculture (USDA) assigns one of three grades to eggs: AA, A, and B. Specific criteria for each of those grades must be met.
Grade AA
These eggs have the highest quality, with firm, thick egg whites and round, well-centered yolks. The shells are clean and free of cracks. Grade AA eggs are ideal for dishes where appearance is important, such as poached or fried eggs. All Petaluma Egg Farm retail eggs are grade AA unless otherwise noted.
Shell: Clean, unbroken, practically normal
Air Cell: 1/8 inch or less in depth. Unlimited movement and free or bubbly.
White: Clear, firm
Yolk: Outline slightly defined. Practically free from defects
Grade A
These eggs have slightly thinner whites than Grade AA, but they still maintain good overall quality. The yolks are fairly round and well-centered, and the shells are clean and unbroken. Grade A eggs are suitable for most cooking purposes, including scrambling, baking, and hard-boiling.
Shell: Clean, unbroken, practically normal
Air Cell: 3/16 inch or less in depth. Unlimited movement and free or bubbly.
White: Clear, reasonably firm
Yolk: Outline fairly well defined. Practically free from defects
Grade B
These eggs have thinner whites and flatter yolks, and the shells may have slight stains or irregularities. Grade B eggs are often used in commercial food production or for making liquid, frozen, or dried egg products. They are less commonly found in grocery stores, but they can still be used for cooking and baking if appearance is not a priority.
Shell: Clean to slightly stained, unbroken, abnormal
Air Cell: 3/16 inch or less in depth. Unlimited movement and free or bubbly.
White: Weak and watery. Small blood and meat spots present.
Yolk: Outline plainly visible. Enlarged and flattened. Clearly visible germ development but not blood. Other serious defects.
What Else Matters?
There are also standards for each of the grades regarding how many checks (eggs that are cracked but the membrane underneath the shell is intact so they are not leaking), leakers (cracked eggs that are leaking), dirties (eggs with adhering dirt or foreign material or excessive stains), and loss (eggs with blood or meat spots) are allowed. In general, these quality factors will have little impact on your cooking or baking experience.
Source: U.S. Department of Agriculture
Who Comes Up with These Standards?
Our eggs are inspected by three different government agricultural agencies: county, state (CDFA), and federal (USDA). They conduct inspections on a regular basis on the farm as well as any place where eggs are sold, with a substantial focus on retail grocery stores. The national standards for egg grades are set by the USDA, and the CDFA chooses to adopt or exceed the USDA standards in some ways.
For example, the USDA bases egg size on the total weight of a dozen eggs, whereas the CDFA bases egg size on the weight of each individual egg. That means that a dozen large eggs under the USDA standard could have some medium eggs mixed in with the large eggs as long as the average weight of the 12 individual eggs equals the weight of a large egg. In contrast, CDFA guidelines require every individual egg in the dozen to weigh at least as much as a standard large egg.
Understanding egg sizes and grades can help you make informed decisions when purchasing eggs for your culinary creations. By choosing the right size and grade, you can ensure that your dishes turn out just as you intended. When in doubt, opt for large, Grade A or AA eggs for most home cooking needs. And remember, no matter the size or grade, farm-fresh eggs from your local egg farm will always be a delicious and nutritious choice.