Eggs as food

• 1. A Soft-Boiled Egg

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  The Babylonian Talmud, a Jewish work from late antiquity, makes a small and surprising claim. "A soft-boiled egg is better than six logs of farina," it states. That single line treats the egg not as a humble breakfast item but as something worth measuring against grain itself. Humans and other hominids have eaten eggs for millions of years, long before anyone wrote a word about them. The most widely consumed eggs come from fowl, above all the chicken. People in Southeast Asia began harvesting chicken eggs for food by 1500 BCE. Yet the chicken is only the start of the story. People also eat the eggs of ducks, ostriches, reptiles, amphibians, and fish, the last of these known as roe or caviar. So how did a wild bird that laid about a dozen eggs a year become a creature that lays more than three hundred? Why does a brown shell cost more in one country and a white shell in another? And why would a person bury an egg in clay for months before eating it? The answers run through ancient tombs, wartime kitchens, and a dispute over broken eggs at a Canadian hotel.

• 2. Tombs And Lent

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  In Thebes, Egypt, the tomb of Haremhab dates to approximately 1420 BCE. Its walls show a man carrying bowls of ostrich eggs and other large eggs, presumably those of the pelican, presented as offerings. Eggs were valuable enough to set before the dead. Chickens reached Sumer and Egypt by 1500 BCE, then arrived in Greece around 800 BCE, where the quail had been the main source of eggs before them. In ancient Rome, meals often began with an egg course, and eggs were preserved by several methods. The Romans crushed their shells in their plates to keep evil spirits from hiding there. In the Middle Ages, eggs were forbidden during Lent because of their richness, but the reason was not purely religious. An annual pause in egg eating let farmers rest their flocks. It also limited the hens' feed at a time of year when food stocks usually ran scarce. Centuries later, in seventeenth-century France, eggs scrambled with acidic fruit juices became popular, and this may have been the origin of lemon curd.

• 3. Drying And Cartons

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  In 1878, a company in St. Louis, Missouri, began turning egg yolk and egg white into a light-brown, meal-like substance through a drying process. The dried egg industry took shape in the nineteenth century, arriving before the frozen egg industry that followed. Production of dried eggs expanded greatly during World War II, supplying the United States Armed Forces and its allies. In 1911, Joseph Coyle invented the egg carton in Smithers, British Columbia. He did so to settle a dispute over broken eggs between a farmer in Bulkley Valley and the owner of the Aldermere Hotel. Early egg cartons were made of paper. Polystyrene cartons grew popular in the latter half of the twentieth century, valued for guarding against heat and breakage. By the twenty-first century, environmental concerns brought back biodegradable paper cartons, often made of recycled material, which once again became widely used. The wild Asian fowl from which domestic chickens descend laid only about a dozen eggs each year during the breeding season. Several millennia of selective breeding produced hens that lay more than three hundred eggs annually, and that lay year round.

• 4. A Global Industry

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  In 2009, an estimated 62.1 million metric tons of eggs were produced worldwide, from a laying flock of roughly 6.4 billion hens. Mass production of chicken eggs is a global industry, though demand and expectation vary by region. By 2017, world production of chicken eggs reached 80.1 million tonnes. China led with 31.3 million tonnes, followed by the United States with 6.3 million, India at 4.8 million, Mexico at 2.8 million, Japan at 2.6 million, and Brazil and Russia at 2.5 million each. In 2023, world hen egg production reached 91 million tonnes, a 77 percent increase from 2000. That growth added 40 million tonnes over the period. For the single month of January 2019, the United States produced 9.41 billion eggs, with 8.2 billion for the table and 1.2 billion for raising chicks. Americans were projected to eat 279 eggs each in 2019, the highest since 1973, yet still below the 405 eggs eaten per person in 1945. The largest egg factory in British Columbia ships 12 million eggs per week.

• 5. Inside The Shell

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  The chalazae take their name from the Greek word for hailstone or hard lump. These one or two spiral bands of tissue suspend the yolk within the white. A bird egg consists of a protective shell, the albumen or white, and the vitellus or yolk, held within thin membranes. A chicken egg resembles a prolate spheroid, with one end larger than the other and symmetry along its long axis. The larger end holds an air cell, which forms as the contents cool and contract after the egg is laid. That air cell is how eggs are graded and aged. A very fresh egg has a small cell and earns a grade of AA, dropping to A and then B as the cell grows and quality falls. Because air enters through pores in the shell as water is lost, an old egg grows less dense and floats in a bowl of water, and a floater should not be eaten. Egg white is about 90 percent water with 10 percent dissolved proteins, almost no fat, and under one percent carbohydrate. It even has uses beyond food, including the preparation of vaccines such as those for influenza.

• 6. Color And Culture

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  Protoporphyrin IX, a precursor of heme, gives a brown egg its color, while biliverdin, a product of heme breakdown, makes shells blue-green. Chicken breeds with white ear lobes generally lay white eggs, and those with red ear lobes lay brown ones. There is no significant link between shell color and nutritional value, yet color drives demand. In most of the United States, eggs are generally white, but brown eggs are common in parts of New England, where a television jingle for years proclaimed "brown eggs are local eggs, and local eggs are fresh!" The Rhode Island Red is among the local breeds that lay brown. Brown eggs are preferred in China, Costa Rica, Ireland, France, and the United Kingdom. In Brazil and Poland, white eggs are seen as industrial, and brown or reddish ones are favored. The New York Times reported during the Second World War that housewives in Boston preferred brown eggs while those in New York preferred white. In February 1976, New Scientist noted that housewives would pay more for brown eggs although white eggs are just as good. In Egypt, brown eggs are hard to find, since the largest supplier calls white ones "table eggs" and packages brown for export.

• 7. Preserved And Transformed

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  Salt is the simplest way to preserve an egg, drawing water out of bacteria and molds so they cannot grow. The Chinese salted duck egg is made by soaking duck eggs in brine, or coating them in a paste of salt and mud or clay. After roughly a month the eggs reach osmotic equilibrium and stop absorbing salt, their yolks turning orange-red and solid while the white stays somewhat liquid. They are often boiled and served with rice congee, and the yolks appear in mooncakes. Pickled eggs take a different path, boiled first and then immersed in vinegar, salt, and spices such as ginger or allspice, with beetroot juice often added for a red color. Left in the mixture for several weeks, the vinegar dissolves much of the shell's calcium carbonate and penetrates the egg, making it acidic enough to inhibit bacteria, so it keeps for a year or more without refrigeration. The most dramatic transformation is the century egg, coated in clay, wood ash, salt, lime, and rice straw for weeks to months. Its alkaline material raises the egg's pH from about 9 to 12 or more, turning the yolk into a dark green cream and the white into a brown jelly. The article describes this as in some way an inorganic version of fermentation.

• 8. Cages And Chicks

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  Laying hens are often euthanized at 100 to 130 weeks of age, when their egg productivity begins to decline. Modern selective breeding has split laying strains from meat strains, and male birds of the laying strain neither lay eggs nor suit meat production, so they are generally killed soon after they hatch. Commercial factory farming often keeps hens in small, crowded cages that prevent natural behaviors like wing-flapping, dust-bathing, scratching, perching, and nest-building. Many caged hens, and some kept cage-free, are debeaked to stop them from harming each other, a practice critics say causes severe pain. Effective the 1st of January 2012, the European Union banned conventional battery cages under EU Directive 1999/74/EC, permitting only enriched furnished cages that meet space and amenity requirements. The EU egg code records the method, beginning with 3 for caged, 1 for free-range, and 0 for organic production. As of June 2023, the killing of male chicks has been banned in Germany, France, Luxembourg, and Italy. Some producers now use in-ovo sexing to identify a chick's sex before it hatches and remove male eggs from incubation. As of April 2025, five companies offer commercial in-ovo sexing, used for 28 percent of the European layer population.