Real Food Encyclopedia | Eggs

Both naturally beautiful and symmetrical, eggs have inspired and fascinated artists, scientists, farmers and cooks for millennia. Chicken eggs are a staple of so many cuisines and are versatile and nutritious. In this country, we devour them for breakfast, lunch and sometimes dinner and use them in baked goods and more.

Starting at the turn of the 20th century, northern California became ground zero for this country’s commercial egg production, beginning with the first commercial hatchery. In 1918, the town of Petaluma opened the country’s first egg ranch, and by 1929 had the country’s largest hatchery. Both the invention of the incubator and the introduction of artificial lighting in chicken coops set the stage for commercial egg production and the beginning of an era of chicken coops, machine-washed, rather than hand-washed, eggs — and ultimately CAFOs (Concentrated Animal Feeding Operations) — factory-farming billions of eggs on a monthly basis. 

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Fun facts about eggs: 

  • The chicken (Gallus domesticus) is believed to have come from various species of jungle fowl native to southeast Asia. According to the “Oxford Companion to Food,” remains from Chinese sites indicate that the birds could have been domesticated as early as 2000 BCE. 
  • The egg cream, the iconic soda fountain drink of New York and Philadelphia, is made from neither eggs nor cream. The treat is a mixture of milk, chocolate syrup and seltzer water whose frothy top resembles beaten egg whites.

What to look for when buying eggs

In addition to the yolk and white (aka albumen), the other interior of a chicken egg contains the chalazae, a network of squiggly white strands that help anchor the yolk inside the white. A prominent bunch of chalazae is a sign of freshness. It is perfectly safe to eat. This basic pictorial gives a quick overview of chicken egg anatomy.  

Curious about how eggs get priced? We have an explainer here.

Size and appearance

Most commercially available chicken eggs weigh from 1.5 to 2.5 ounces, and their sizes are determined by the USDA: Small (1.5 ounces); Medium (1.75 ounces); Large (2 ounces); Extra Large (2.25 ounces); Jumbo (2.5 ounces ).

The USDA also grades eggs at the request of an egg producer, using AA, A and B, based on “the appearance and condition of the egg shell” as well as the quality of the yolk and white. The color of the yolk depends on what the hen eats. Traditionally, if it’s free to roam and eat plants and flowers on pasture, its yolk will be a more intense yellow or even orange. If the hen feeds on corn and soybean meal in confined conditions, the yolk will be lighter in color. But these colors can also be impacted by feed and supplements, and as orange has become a desirable color, producers have started to chase that color in various ways.

Occasionally, blood spots appear on the yolk. They are the result of a ruptured blood vessel and are harmless. You can remove it with the tip of a knife. 

Eggshell color is not an indicator of flavor, nutritive value or quality, but of chicken breed. A hen with white earlobes will lay white eggs, and a hen with red earlobes will lay brown, blue or green eggs. Farmers’ market shoppers may encounter gorgeous blue/green eggs from the Araucana and Ameraucana breeds. 

Food Label Guide

Labels

Egg labels are complicated. Several labels are downright meaningless, because they have no legal definition or are not verified by a third-party inspector. These include “natural,” “humane” and even “pasture-raised.” “Hormone-free” is misleading, as chickens are raised without growth hormones in the first place.

When it comes to cage-free, you should understand that the “cage-free” barns are often hardly better for hens than battery cages; there also is no difference between the two systems in terms of their respective environmental impact.

Whenever possible, buy eggs from an individual who can speak directly to the diet and living conditions of the hens, whether they have access to the outdoors, the size of the flock and how the hens are cared for. At the store, look for eggs that have been independently certified; we’re fans of: 

If you’d like to take matters into your own hands, you may want to consider backyard chicken farming, a practice that is experiencing a revival in cities and suburbs around the country. Start by researching the local chicken-farming ordinances where you live. Online communities such as Backyard Chickens include everything you need to know, from building a coop to raising chicks. 

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Sustainability of eggs

Foodborne illness

In 2010, factory farmed eggs were at the center of a multi-state salmonella outbreak that resulted in a nationwide recall of more than half a billion eggs, which the FDA characterized as one of the largest recalls in recent history. According to the Centers for Disease Control and Prevention (CDC), approximately 1,939 people became sick from salmonella associated with the outbreak over a seven-month period in 2010. The responsible party was DeCoster Egg Farms, a multi-state operation headquartered in Iowa and the third largest producer in the country at that time. The outbreak prompted a Congressional hearing as well as criminal and civil lawsuits. In 2011, DeCoster got out of the egg business.  

The DeCoster episode is a dramatic illustration of the pitfalls of industrialized agriculture. According to the American Egg Board, 95 percent of all laying hens are under the control of just 247 companies. 59 of those companies oversee flocks of 1 million-plus hens. When we think of CAFOs, we tend to think of cattle or pigs, but these numbers show us that eggs are no different.

For a deep dive on egg production and its sustainability issues, please read our report, The FoodPrint of Eggs.

Seasonality

Egg-laying hens are extremely light sensitive and are most productive from the vernal equinox to late summer, when there is at least 12 hours of daylight. Farmers’ market shoppers (and backyard chicken farmers) know firsthand that as the days get shorter, production slows down, and there are fewer eggs for sale. They are a year-round commodity because hens live indoors under artificial light. But even under these conditions, they still need 10 hours of light a day. 

Eating eggs

Storing

Eggs are extremely porous and readily absorb odors, so keep in cartons rather than those trays built into the door of your refrigerator. Leftover whites freeze well (particularly in ice cube trays), but yolks don’t do as well in the freezer. Store yolks in a small airtight container and use up within a few days. 

Cooking with less waste

Cooking

Let’s get cracking: tap the side of the egg on a hard surface, but not your main mixing bowl or skillet. When adding them to a batter, always crack into a smaller bowl, not directly into the mixture, in case of shell breakage or egg defects. 

Here’s a sampler of the myriad ways you can have fun with eggs:

  • Coddled: Cook individually in cups and gently steam in a water bath (aka bain marie)
  • Shirred: Aka oeufs en cocotte, bake with cream and cheese
  • Poached: Pour into a shallow pan and cook gently in a simmering liquid
  • Hard-cooked: Otherwise known as hard-boiled, cook in boiling water (time recommendations vary!), until both the yolk and white solidify. Place in ice water for 5 minutes to ease peeling. 
  • Deviled/Stuffed:  Peel and slice cooked eggs in half. Scoop out yolks and season with mustard, mayonnaise and a variety of spices. Stuff yolk filling back into the white halves. 
  • Scrambled: Beat, then cook in fat over low-medium heat, then stir to create gently “scrambled” curds. For the most voluptuous of curds, try them this way, with a whisk, and a few pats of butter.
  • Omelet: Pour beaten eggs into a hot skillet and cook vigorously with a fork, then fold. (Fillings optional.)
  • Fried eggs: Sunny side up means fried on just one side, with a still-runny yolk and the whites barely set. “Over easy” means that the egg will get folded in half, and the egg is still slightly runny. Keep cooking for another minute or so, and you’ll have an egg “over medium.”

And that barely scratches the surface. There are a slew of egg-based emulsified sauces, from mayonnaise to hollandaise. Then there are pies (fritattas) and tarts (quiches), and battered goodies, like French toast, egg whites beaten and baked into meringues or egg custards frozen into ice cream.

Nutrition

Nutritional vice or virtue? That’s the question Americans have been asking about the egg over the past four decades. On the one hand, the egg is high in protein, with more than 6 grams in a large egg — at just 72 calories. On the other hand, the egg is undisputedly high in cholesterol — about 215 milligrams — about three-fourths of the daily maximum recommended by the American Heart Association (AHA). Concerned about dietary cholesterol’s link to higher risk of heart disease, the medical community went on the egg offensive in the 1970s and 1980s. The American Heart Association issued guidelines in 1972 recommending a maximum of three eggs per week. (Ironically, it was the same year that the high-fat/low-carb “Dr. Atkins’ Diet Revolution” was first published). But two major studies published in 1999 were instrumental in changing public perception about eggs.

Harvard researchers found that moderate egg consumption — up to 1 egg per day — did not increase the risk of heart disease among healthy people and because of its vast reserve of many other nutrients, could be part of a healthy diet. In 2000, the AHA, citing the Harvard studies, relaxed its recommendations for dietary cholesterol and cautiously permitted “periodic consumption of eggs and shellfish.”

As for its other nutritional benefits, the egg, particularly the yolk, is rich in Vitamins A and D. It is also an excellent source of choline, a little-known B vitamin that supports the nervous system, the brain and liver detoxification, to name a few. In fact, the egg serves up all the B vitamins:  B-1, B-2, B-3, B-5, B-6, B-12, biotin and folic acid. It’s well endowed with several minerals, including manganese, selenium and iodine. The one thing it’s lacking? Fiber. 

Despite its wellspring of nutrients, the egg is a common food allergen. After cow’s milk, the egg is one of the most common food allergies among children. Because certain vaccines contain egg protein, we recommend consulting your medical provider before any immunizations. 

Top photo by Erol Ahmed on Unsplash.