Believe, dear friend, that no alchemist ever produced from furnace or alembic, so rare a treasure as you may obtain from hens, if you only know how to combine labour and delight.
(Prudent Le Choyselat, 1612)
In 1751, the most ambitious publishing project of the eighteenth century was launched with the Encyclopédie, which aimed to encompass all knowledge of the time. Eggs were wholesome and highly nutritious, and it was believed that egg yolks were an aphrodisiac, increasing the quantity of sperm produced and promoting the sexual appetite.1 Touted for its medicinal attributes, a poached egg with one to six drops of cinnamon oil was thought to ease prolonged labour; drunk before bedtime, egg yolk, hot water and sugar was a cure for coughs and a treatment of bilious colic; and yolks, mixed with turpentine or other natural balsams, aided digestion, certainly a questionable prescription today. Egg whites were used to prevent swelling, and to clarify pharmaceutical extracts and medicinal jellies such as the nourishing restorative Hartshorn.
‘One uses it, in Medicine, for its glutinous and astringent qualities,’ according to the Encyclopédie.
In this case one often mixes it with Armenic bole, etc., to prevent swelling in areas which suffered some violence, and to restore to the fibers their resilience and elasticity; that which one calls a preventative. It also enters in some mixes to heal recent wounds and prevent hemorrhaging.
Egg whites were also used in wine fermentation, and by bookbinders and gilders to make book spines sticky before applying gold leaf, as well as to give a lustrous shine to book covers. ‘Gilders use egg white to glaire [or coat] the spine and other places two or three times with a very fine sponge, before applying the gold there once the egg white is dry,’ explains the Encyclopédie.
One uses the egg white again to give the covers a shine. When the book is entirely finished, one lightly wipes the entire covering with a fine sponge dipped in the egg white, and when it is dry one goes over it with the polishing iron.2
Leather workers also soaked the high heels of delicate ladies’ shoes in egg whites before dying them with red ochre, a fashion statement at the time.
Simple in shape and elegant in appearance, an egg (in Latin, ovum) is pregnant with possibilities. Whether laid by a bantam, chicken, duck, gull, goose, guinea fowl, ostrich, partridge, pheasant, quail or turtle, an egg is oval (or egg shaped), usually with one end larger than the other. The one exception in birds’ eggs is the perfectly round egg of an albatross – perhaps the reason why it is the only egg that is associated with bad luck. Dating back to an Indo-European root, cheeka/e, one who lays eggs, the derivation of the word egg comes from the Old English oeg. It survived in Middle English as ey, but in the fourteenth century the related ‘egg’ was borrowed from Old Norse, and has since become the common reference. ‘Yolk’, from the Old English word for yellow, has an Indo-European root meaning to ‘gleam’ or ‘glitter’.3
‘It may be the cock that crows, but it is the hen that lays the eggs,’ observed Baroness Margaret Thatcher (1925–2013), Great Britain’s first woman prime minister. No animal works harder than a hen to reproduce, and her effort, or fraction of body weight deposited daily in her future offspring, is 100 times greater than a human’s. Each egg is about 3 per cent of her weight, so in a year of laying she converts about eight times her body weight into eggs, and a quarter of her daily energy goes towards making them. A labour of love, it takes her 24 to 26 hours to produce an egg, then she rests for 30 minutes, and begins the process all over again. She usually lays twelve eggs, called a clutch, at a time between seven and eleven in the morning, and if they are not collected, she may stop laying and start brooding.
Mrs Beeton’s 'Book of Household Management', published in Britain in 1859, pointed out correctly that ‘Eggs contain, for their volume, a greater quantity of nutriment than any other article of food.’ The author’s sage advice about choosing eggs was to, ‘Apply the tongue to the large end of the egg, and if it feels warm, it is new, and may be relied upon as a fresh egg.’4 Happily, it is easier today to determine whether an egg is fresh – it sinks in a bowl of water, while older eggs float. As an egg ages, air is absorbed though the shell and it loses water and carbon dioxide through the pores, making it lighter.
Biologically a reproductive unit produced by the female, an egg allows for the continuation of life, and builds a bridge between generations. After the egg cell, consisting of a ball of yolk, is fertilized, it slides down the uterine tube where the egg white (which protects the foetus and supplements the water and protein in the yolk) and shell form an egg. Each eggshell (about 12 per cent of its total weight) is composed largely of calcite, a fibre-reinforced calcium carbonate. The albumen, or white, makes up about 58 per cent, and the yolk (about 30 per cent) is anchored in place by rope-like strands of egg white called chalazae. At the rounded end of the egg is a protective pocket of air, known as the air cell or air chamber. Appearing smooth, an eggshell actually contains tiny pores (as many as 17,000) to allow moisture and carbon dioxide out and air in. When laid, an egg is warm (40ºC/105ºF), and as it cools the liquid contents contract, and the inner and outer shell membranes separate at the large side of the egg.
Although an egg is fragile looking, its oval shape gives it remarkable strength, and it can bear extraordinary weight on its convex surface before breaking. To determine what it takes for eggs to crack under pressure, scientists found that the average weight needed to crush a chicken egg is about 4½ kg (10 lb), 6 kg (13 lb) for a turkey’s egg, 12 kg (26 lb) for a swan’s egg and 54 kg (120 lb) for a tough-shelled ostrich egg.5 Curiously, you cannot break an egg by cupping it in the palm of your hand and squeezing because eggs are similar in shape to a three-dimensional arch, one of the strongest architectural forms. When you surround the egg with your hand, the curved form of the shell distributes pressure evenly over the shell rather than concentrating it at any one point.6
‘The egg is a small physical thing with a beautiful geometrical surface,’ wrote Martin Gardner (1914–2010), mathematics and science writer for 'Scientific American'.
It is a microcosm that obeys all the laws of the universe. And at the same time it’s something far more complex and mysterious than a white pebble. It is a strange lidless box that holds the secret of life itself.
It is little wonder that the egg has been described as one of the best pieces of packaging design in the world. Amazingly, the shell is hard enough to protect the embryo in hot and dry climates, and ancient shepherds in the Middle East discovered that if they placed a raw egg in a sling and whirled it around and around, the rapid motion produced heat, cooking the egg. These tasty packets can be kept for weeks with very little care, contain natural antimicrobial defences, making them safe for humans to eat, and are portable enough to be carried for sustenance on travels and adventures.
Occasionally – once in every 530 eggs – a hen produces double-yolk eggs during her egg-laying career, but triple-yolkers only occur once in every 5,000 eggs. It is also rare for a young hen to produce an egg with no yolk at all, something that is considered by many to be unlucky. We could not say for certain that the hen would feel the loss. In 2008, students at Yokaichi Minami High School in Japan raised a chicken that laid a large egg (8.1 cm/3¼ in and 158 g/5½ oz), which got so much attention that the school decided to put it on display. Noticing a small crack, the teachers removed the shell, and found within another perfectly formed, medium-size egg. A year later the same oddity was noted by Jeff Taylor, in Ross-on-Wye, Herefordshire, in Britain; he cracked open a free-range boiled egg for his breakfast, and was shocked to find a smaller intact egg inside.
With an estimated 19 billion chickens around the globe, according to the United Nations Bahrain has the most chickens, at 40 per capita. Nearly 200 breeds and varieties exist worldwide, and the average egg-laying hen produces 270 eggs per year, almost one a day on average, weighing in at about 50 g (2 oz). Since size does matter, the largest and heaviest chicken egg in the world was laid by a Byelorussian chicken, weighing a whopping 146 g (5 oz), according to the Guinness World Records. In contrast, small bantam chickens lay eggs half the size of regular eggs, and chickens under a year old lay even smaller pullet eggs.
Fortunately chefs all over the world continue to ignore the riddle, ‘When are cooks cruel? When they whip the eggs and beat the cream.’ However, another question, ‘Does anybody have a formula to calculate the boiling time for a soft-boiled egg; given its weight and initial temperature?’ bothered a reader of New Scientist magazine. Eager to be of service, Professor C.D.H. Williams, of the University of Exeter’s School of Physics, came up with the formula.7
Timing is everything. When eggs are cooked too long, at too high a temperature, or if the cooking water contains excessive iron, a sulphur and iron reaction can occur resulting in a greenish colour around the yolk. Scrambled eggs, too, can develop a greenish tint if they are left too long in a metal pan, although in both cases the eggs are still wholesome and flavour is unaffected. However, you do not have to brood if your cooked egg does not turn out as you wish. Physical chemist and molecular gastronomer Hervé This said you could uncook an egg with sodium borohydride, which uncoils the disulfide bridges made by heat.8 He explains that when an egg is cooked, the protein molecules unroll themselves, link up and enclose the water molecules. To ‘uncook’ the egg you need to detach the protein molecules from each other. By adding sodium borohydride, the egg becomes liquid within three hours. For those who want to try this at home, vitamin C also does the trick.
Practice makes perfect for most professional cooks, who use one hand to crack an egg into a bowl. Bob Blumer, host of the American television series Glutton for Punishment on the Food Network, set the world record for most eggs cracked in an hour using just one hand. To best his record you would have to crack 2,071 eggs. Although he cracked 2,318 eggs, 248 were disqualified because they contained broken eggshells. When you use eggs in a recipe, break them into a separate container, so that if a shell piece falls in you can remove it.
Edible Egg Varieties
A variety of egg types apart from chicken eggs are popular food fare. Duck eggs, off-white in colour, higher in fat content and favoured in China, are oily tasting, but can be eaten in the same way as chicken eggs or used in baking. When boiled the white turns bluish, and the yolk a reddish-orange colour.
White shelled and four or five times larger than chicken eggs, goose eggs have an oily, rich taste. They are larger than light tan or ivory-coloured peacock eggs, which are about three times the size of chicken eggs. Actually, peacocks do not lay eggs; the female is a peahen. Cream coloured and specked with brown, turkey eggs are sometimes twice the size and similar in taste to chicken’s eggs, so are often used as substitutes for them.9 A speckled, iridescent ostrich egg – twenty times the size of a chicken’s egg – is edible to someone with an expansive appetite, if it has not been left to bake in the sun. On the smaller end of the size scale are guinea fowl eggs. Flecked with brown, they have a more delicate taste than a chicken’s egg, and are often pickled, served hard-boiled in salads or set in aspic. Partridge eggs are white, buff or olive, although some have brown or black blotches to protect them against predators. Speckled brown quail eggs are one-third the size of a chicken’s egg, and can be prepared hard-boiled, poached or in aspic. A pale rosy colour, pheasant eggs are similar in size to quails’ eggs, and can be cooked in a variety of ways.
The most unique and prized eggs come from China. Salted duck egg is a Chinese preserved food product made by soaking duck eggs in brine, or packing them in damp, salted charcoal. In Asian supermarkets these eggs are often sold covered in a thick layer of salted charcoal paste, or vacuum packed without the paste. From the salt-curing process the duck eggs have a briny aroma, a very liquid egg white and a sharp, salty taste, and the yolk is bright orange-red in hue with a rich, fatty, but less salty taste. Normally boiled or steamed before peeling, salted duck eggs are eaten as a condiment for congee, a type of rice porridge, and cooked with other foods as a flavouring; the yolk is prized and is used in celebratory Chinese mooncakes. Marble eggs, sold by street vendors and eaten as a snack between acts at the Chinese opera, are boiled and steeped in a spicy tea mixture, which gives them a beautiful marbled appearance. Ming Dynasty eggs, fermented eggs, ancient eggs, century eggs, thousand-year-old eggs and hundred-year-old eggs are all names for the Chinese preserved duck eggs, which are covered with a coating of lime, ashes, salt and rice straw, and buried in shallow holes for up to 100 days (certainly not 1,000 years). Lime petrifies the eggs, making them look very old, and the yolks turn from amber to black with a creamy, dark green yolk. They are eaten uncooked with soy sauce and minced ginger.
Of all the edible eggs in the world, the most expensive, opulent and indulgent are fish eggs. They contain all the nutrients that one cell needs to grow into a hatchling, and are a more concentrated form of nourishment than the fish itself. A protein-rich fluid, fat-soluble carotenoid pigments, and building-block amino acids and nucleic acids surround the inner yolk of a fish egg. Roe consists of separate eggs held together in a dilute protein solution enclosed in a thin, fragile membrane.
Caviar, the salted roe of the sturgeon, is the most valued and in demand, even as civilization has encroached on its source from the landlocked Caspian Sea, which lies between Iran and Russia, putting beluga, osetra and sevruga sturgeons on the World Wildlife Foundation’s Endangered Species List. The word ‘caviar’ comes from the Persian khavyar, from khayah, or egg. While Western Europeans and Americans use the word caviar (it came into the English language in the sixteenth century), the Russians do not. They refer to fish roe of all kinds as ikroj (pronounced EEK-ruh with a rolled ‘r’; the Japanese adapted the word to ikura). Today, white sturgeon and hackleback sturgeon are farmed in freshwater lakes or tanks in the Pacific Northwest, California and the South, using environmentally conscious and sustainable practices, making the United States a player on the world caviar scene. Other fish eggs come from bowfin, carp, cod, pollack, flying fish, grey mullet, hake, herring, lobster (eggs are referred to as coral), lumpfish, paddlefish, salmon, shad, shaker, smelt, trout, tuna and whitefish. In fact, most fish roe is edible, but that of some species, including the great barracuda and some members of the puffer (fugu) and trunkfish families, is toxic. Roe can be sautéed, poached or, providing it is of medium size or larger, broiled. It can also be used in sauces or to top them. The eggs of a fish are also called berries, pearls and grains. In the caviar trade, once the roe has been salted it becomes caviar.
An age-old belief in the aphrodisiac power of turtle eggs sustains a thriving black market for the forbidden ovum through out Latin America. Most countries have banned the collection of these eggs because the world’s seven sea turtle species are highly endangered by disease, fishing nets, disturbance of nesting areas and poaching of the eggs. Turtles lay their eggs in the sand on the beach, and birds and other predators, including humans, hunt for the eggs.
Alligator eggs (also the name of a shrimp-stuffed jalapeño in Cajun cooking) have a unique mild, rich flavour, making them an acquired taste. The soft shell is buff or speckled. There is another notable edible egg variety that might pique one’s curiosity. When Dr Stanley Livingston tasted crocodile eggs during his Zambezi Expedition in Africa from 1858 to 1864, he remarked:
In taste they resemble hens’ eggs, with perhaps a smack of custard, and would be as highly relished by whites as blacks were it not for their unsavoury origin in man-eaters.
Arab traders in the 1300s told tales of a bird so gigantic that it could lift elephants. Sailors told them it was hunted on an island off the southern coast of Africa. Lest you think this was just a fable, archaeologists later found evidence of Aepyornis (the elephant bird) on Madagascar. The largest bird that ever lived, it was 3½ m (10 ft) tall and weighed about a half a ton. Its eggs were the largest ever recorded at over 8 litres (14 pints). Although Aepyornis could not possibly lift an elephant, the theory was never tested because no elephants lived on Madagascar. Perhaps fear of being snatched up by giant talons was the reason for the use by the Arabs of the expression ‘Walking on eggshells’, meaning being careful.
NOTES
1 Urbain de Vandenesse, ‘Egg White’, The Encyclopedia of Diderot et d’Alembert, Collaborative Translation Project, trans. A. Wendler Uhteg, University of Michigan Library (Ann Arbor, MI, 2011). Originally published as ‘Blanc d’oeuf ’, Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers (Paris, 1752), vol. II, p. 272.
2 Ibid.
3 John Ayto, An A–Z of Food and Drink (Oxford and New York, 2002), p. 117.
4 Isabella Beeton, Mrs Beeton’s Book of Household Management, 3rd edn (New York, 1977), p. 823.
5 Dal Stivens, The Incredible Egg: A Billion Year Journey (New York, 1974), p. 318.
6 Gareth Huw Davies, ‘The Life of Birds: Parenthood’, www.pbs.org/lifeofbirds, accessed 28 August 2013.
7 Ian Phillips, ‘The Man Who Unboiled an Egg’, The Observer (19 February 2010).
8 Kent Steinriede, ‘Food, With a Side of Science’, Scientist Magazine, Ontario (July 2012).
9 Philip Dowell and Adrian Bailey, Cooks’ Ingredients (New York, 1980), p. 236.
Written by Diane Toops in "Eggs - A Global Story", Realktion Books, London, UK, 2014, excerpts chapter one. Digitized, adapted and illustrated to be posted by Leopoldo Costa.
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