Eggs

Eggs. Melanie F. Hardy / pixabay.com / 2015 / CC0 1.0

An egg is an oval or round organic object, laid by a female bird, reptile, fish, or invertebrate, in which an embryo develops and grows to become the young of the species. In the world of cooking, the term is generally taken to mean bird eggs, and more specifically, chicken eggs. (Caviar is a term generally used for fish eggs.)

“The types of egg eaten include hen, duck, goose, plover, quail, turkey, etc.” ^[1]Pellaprat, H.P. Modern French Culinary Art. London: Virtue & Company Ltd. 1969. Page 267.

Egg size comparison. © CooksInfo / 2014

See also: Egg Day, World Egg Day

Uses for eggs

In the English-speaking world, eggs are largely a breakfast item. This is not so with the French. Julia Child observed that “the French, who do not eat eggs for breakfast, have put much of their ingenuity into eggs for any other meal.” ^[2]Child, Julia. The French Chef Cookbook. New York: Alfred A. Knopf. 1968. Page 102.

Egg acts as a thickener because as heat energy is applied, the proteins in it unfold, and come into contact with each other and bond. The higher the heat, they more tightly they cling to each other. Heated and cooked past that, the protein bonding starts to break down and release the water they had held: the water runs off, and what gets left is the rubbery protein.

Eggs can be used as food items on their own, or as ingredients. When used as ingredients, they are usually used either to bind, or to help something rise.

H.P. Pellarat, co-founder of the Cordon Bleu Cooking School in Paris, wrote:

“Eggs are very valuable in cookery because of their versatility. They are used to thicken soups and sauces, to bind ingredients together, as a means of incorporating air into mixtures and to coat food for frying. They are also served on their own and cooked in a great variety of ways… Egg dishes are usually quick to prepare and are invaluable when time is short or unexpected guests arrive. In addition to all these virtues eggs are economical and nutritious as they are rich in valuable proteins, vitamins, fat, and mineral salts.” ^[3]Pellaprat, H.P. Modern French Culinary Art. Page 267.

Delia Smith is considered perhaps to be the queen of cooking eggs in England. She wrote:

“Eggs are a supremely important ingredient in the kitchen, serving the cook in any number of ways. They can thicken soups and sauces, set liquids and baked dishes, they can provide a glorious airy foam to lighten textures and will also, quite miraculously, emulsify oils and butter into a rich smoothness.” ^[4]Smith, Delia. How to Cook: Book One. London: BBC Worldwide. 1998. Page 12.

If you are buying eggs with an eye to whipping egg whites, smaller eggs are actually better: their whites are more concentrated, less diluted with water.

Diluting eggs makes it harder for the protein molecules to coagulate together, as they are further apart. Sugar has the same effect, because its molecules coat each protein molecule making it harder for them to bond with each other. Salt and acid, on the other hand, speed coagulation.

Egg Sizes

Egg size comparison: UK, US, Canada

In terms of how much weight of egg a consumer gets for an egg designated large, small, etc., British consumers get the most egg, followed by American consumers. Canadian consumers get the least.

Egg weight per dozen US

In the United States, though eggs are ostensibly sold by size per dozen, they are actually sold by weight per dozen. 1 dozen large eggs will weigh 680 g (1 ½ pounds.) Small eggs can often be the best buy, in terms of price per pound. Consumers often buy large eggs, however, because a recipe calls for them, and people don’t know the ratio for swapping in small or medium eggs. (Table src: El-Begearmi, Mahmoud. Bulletin #2257, Food Safety Facts: Facts About Eggs. University of Maine Cooperative Extension.)

Eggs in the UK: The Red Lion scheme

English egg carton with Red Lion stamp on it. © CooksInfo / 2020

The UK egg industry does not wash its retail eggs. Because of this (see Washing Eggs section), eggs are not sold at supermarkets in chillers. They are displayed out on regular, unrefrigerated shelves.

Close to 95% of eggs sold in the UK are individually both date stamped, and stamped with a Red Lion logo. It means that the eggs came from hens vaccinated against salmonella, ^[5]”Look for the British Lion mark to guarantee that the eggs have come from hens vaccinated against salmonella.” Egg Info. Egg storage and handling. Accessed August 2020 at https://www.egginfo.co.uk/egg-safety/storage-and-handling and you can use them safely in items where eggs don’t get cooked fully or at all, such as mayonnaise. Eggs used in the restaurant business, however, may come from outside the UK and therefore outside of the Red Lion scheme.

The scheme of vaccinating the hens in England has caused the number of cases of salmonella cases there to drop drastically (and bear in mind that people can still contract salmonella from sources other than eggs:

“Since the late 1990’s, British farmers have been vaccinating hens against salmonella following a crisis that sickened thousands of people who had consumed infected eggs.  Amazingly, this measure has virtually wiped out the health threat in Britain. In 1997, there were 14,771 reported cases of salmonella poisoning there, by 2009 this had dropped to just 581 cases. About 90 percent of British eggs now come from vaccinated hens – it’s required for producers who want to belong to the Lion scheme. The remaining 10 percent come from very small farmers who don’t sell to major retailers.”  ^[6]Arumugam, Nadia. Why American Eggs Would Be Illegal In A British Supermarket, And Vice Versa. Forbes Magazine: 25 October 2012. Accessed August 2020 at https://www.forbes.com/sites/nadiaarumugam/2012/10/25/why-american-eggs-would-be-illegal-in-a-british-supermarket-and-vice-versa/

Delia Smith explains the best-before date on British eggs:

“What you should know is that this [best before] date, provided the box is stamped with the lion mark, corresponds precisely to 21 days after laying (not packing), so you are, therefore, able to work out just how fresh your eggs are.” ^[7]Smith, Delia. How to Cook: Book One. London: BBC Worldwide. 1998. Page 14.

English egg with date and Red Lion stamp on it. © CooksInfo / 2020

Eggs in the EU

In the EU, as of 1 January 2004, all eggs sold retail have to be stamped with a producer code that identifies the country and production method, as well as the farm or origin. Eggs sold from the farm or door to door don’t have to be stamped (as the assumption is that the origin is already known.)

1st digit of code = circumstances under which the egg was laid.
0 = organic
1 = free range
2 = free range indoors
3 = battery or cage

The letters following this show country of origin. The last 5 digits are a number representing the farm.

The code is followed by a BB — best before — date. The best before date can be no more than 3 weeks after the laying date. Stores cannot sell to consumers eggs more than 3 weeks old.

Eggs in the US: Grading

There are three grades of eggs in the U.S. sold to consumers:

• USDA Grade AA – The freshest and highest quality eggs. Must have clean, uncracked shells;
• USDA Grade A – Very high quality eggs. Must have clean, uncracked shells;
• USDA Grade B – Typically used for liquid eggs and baking. ^[8]USDA Agricultural Marketing Service. Shell Egg Grades. Accessed August 2020 at https://www.ams.usda.gov/grades-standards/egg/grade-shields

If you see a grade with a shield, that means it has been inspected under federally monitored conditions. A grade without a shield means the processor operated under state regulations.

Cartons with a shield on them will also have a three-digit number on them. That indicates what day of the year the carton was packed on. For instance, 034 means it was packed on February 3. ^[9]El-Begearmi, Mahmoud. Bulletin #2257, Food Safety Facts: Facts About Eggs. University of Maine Extension Cooperative Extension. 2002.

Fertile and blood-spotted eggs

When purchasing eggs at the grocery store, there is almost no chance you will get a fertile egg, simply because no roosters are kept in with the hens. You may, however, encounter one in an egg purchased at the farm gate, or at health food stores. These can be eaten because unless the egg has also been incubated, no growth inside the egg will have occurred: “There are no nutritional differences between fertile and infertile eggs. If fertile eggs are not incubated there will be no development of the embryo and no way to distinguish them from infertile eggs.” It is illegal to sell incubated eggs for human consumption in the U.S. ^[10]El-Begearmi, Mahmoud. Bulletin #2257, Food Safety Facts: Facts About Eggs. University of Maine Extension Cooperative Extension. 2002.

A blood spot in an egg does not mean the egg is fertile. It just means a blood vessel ruptured in the hen while the egg was being laid. Some breeds are more prone to this than others. In the U.S., small blood spots are permitted in Grade B eggs. There is a slight allowance for them in Grades AA and A eggs because very small spots can be difficult to detect, especially if the eggs have brown shells.

Washing eggs

Once eggs are washed in processing, they require refrigeration afterward because washing removes the cuticle on the shell that helps to keep freshness in and bacteria out. There are different views about the efficacy of washing eggs during processing at the packers, but once you do, what’s certain is that the expense of keeping eggs chilled until use has now been added to their cost. This includes supermarkets having to purchase and run chiller cabinets for them.

Where are eggs washed?

In the U.S., Canada, and Japan eggs are washed at processing plants before they are packed for sale to consumers to remove any surface contaminants on the shells. (Egg washing by processors is optional in Australia, New Zealand, South Africa, and Sweden.) ^[11]Both washed and unwashed eggs are sold in Sweden. Report from the Commission to the Council with regard to developments in consumption, washing and marking of eggs. EUR-Lex – 52003DC0479 – EN. 2003. Accessed August 2020 at https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:52003DC0479 ^[12]Egg Cleaning Procedures. Department of Primary Industries, New South Wales, Australia. August 2015. ^[13] Egg Quality Maintenance: Poultry Farming in South Africa. Accessed August 2020 at http://southafrica.co.za/egg-quality-maintenance.html

“The USDA requires producers to wash eggs with warm water at least 20°F warmer than the internal temperature of the eggs and at a minimum of 90°F. A detergent that won’t impart any foreign odors to the eggs must also be used. After washing, the eggs must be rinsed with a warm water spray containing a chemical sanitizer to remove any remaining bacteria.  They are then dried to remove excess moisture.” ^[14]Arumugam, Nadia. Why American Eggs Would Be Illegal In A British Supermarket, And Vice Versa. Forbes Magazine: 25 October 2012. Accessed August 2020 at https://www.forbes.com/sites/nadiaarumugam/2012/10/25/why-american-eggs-would-be-illegal-in-a-british-supermarket-and-vice-versa/

University of Wisconsin–Madison poultry specialist Ron Kean says the washing provides two benefits: “There are two benefits of washing eggs: one, it gets rid of any surface contaminates, and two, it provides a cleaner, nicer looking egg.” ^[15]Fox, Tyler. Most of the world does not refrigerate their eggs. So why does the US? University of Wisconsin–Madison Science News. 12 September 2018. Accessed August 2020 at https://uwmadscience.news.wisc.edu/animals/most-of-the-world-does-not-refrigerate-their-eggs-so-why-does-the-us/

The downside to washing eggs is that the washing removes a protective coating on the shell called the “cuticle”. Removing this protective barrier lets bacteria enter the egg, and, reduces its shelf life.

Processing oil on egg shells

To compensate for the cuticle being washed off, the eggs are then typically coated with a thin layer of mineral or vegetable oil, ^[16]”Egg processors will sometimes spray eggs with mineral oil or food oil to retain moisture and prevent bacteria from penetrating the shell” O’Brien, Dennis. USDA Agricultural Research Service. How We Store Our Eggs—and Why. Accessed August 2020 at https://tellus.ars.usda.gov/stories/articles/how-we-store-our-eggs-and-why/ and then put into a refrigeration chain that must not be broken from processor to consumer use.

Several different types of oil have been tried but food-grade mineral oil has been found to be the best:

“The egg shell surface has 7000 to 17000 pores that allow moisture and carbon dioxide to get out and air to get inside. Therefore, oil can be applied on the surface of shell eggs to seal these pores, resulting in reduction of carbon dioxide and moisture loss, and contamination of microorganism. Thus, most of carbon dioxide is still retained inside and albumen pH change is minimal. Previous studies have revealed that the oil-coated eggs have significantly better quality than noncoated eggs because coating reduced weight loss and preserved interior quality; the types of oils investigated include mineral oil, polydimethylsiloxane fluids, linseed oil, groundnut oil, cottonseed oil, and coconut oil. However, mineral oils have been recommended for applying to the egg shell due to a slow rate of evaporation. Food-grade mineral oil is odorless, tasteless, and colorless.” ^[17]Waimaleongora-Ek, Pamarin, et al. “Selected Quality and Shelf Life of Eggs Coated with Mineral Oil with Different Viscosities.” Journal of Food Science, vol. 74, no. 9, 2009, pp. S423–29. Crossref, doi:10.1111/j.1750-3841.2009.01341.x.

Where are eggs not washed?

Most of the world does not wash its eggs. They are not washed in the United Kingdom, or Ireland.

The practice is forbidden in the European Union for class A eggs, though Sweden has an exception owing to long-standing consumer preference there.

The reason given is that egg shells can easily allow detergents to pass through into the eggs, and, because egg shells have an outer layer on them called the “cuticle”, which blocks the porous surface of the shell, keeping freshness in and microbes out, but which is destroyed by washing:

“The practice of washing eggs of class A for human consumption is forbidden by the European Union legislation. A fresh egg of class A should be produced in a way that ensures it is fit for human consumption. Washed eggs should be downgraded… a cuticle membrane, that is an organic layer, covers the whole surface of an egg. Under normal conditions and good handling practices, the cuticle protects the egg against dehydration and offers a natural barrier to the common contaminants present in the flora that colonises the surface of the egg. The egg content can be contaminated in a vertical way, when the layer’s ovaries or oviduct are infected, and in a horizontal way, when contaminants, originating for example from faecal material or dust in the nest, can get through the shell inside the egg. The washing of eggs cannot change the situation of a vertical transmission of contaminants. In case of a horizontal transmission, the cuticle offers a natural barrier and when not handled properly, damage of the cuticle can cause a higher fragility of the egg and the risk of contamination of its content rises…

The washing of table eggs of class A is not permitted by European legislation. Article 5(2) of Commission Regulation (EEC) No 1274/91 of 15 May 1991 introducing detailed rules for implementing Regulation (EEC) No 1907/90 on certain marketing standards for eggs states that “Grade ‘A’ eggs shall not be washed or cleaned by any other means before or after grading.” Because of this provision, washed eggs must be downgraded to class B eggs but this practise is rarely applied within EU, with the exception of Sweden.” ^[18]Report from the Commission to the Council with regard to developments in consumption, washing and marking of eggs. EUR-Lex – 52003DC0479 – EN. 2003.

If eggs are not washed by the processor, then in theory, they do not require refrigeration for safety the way that washed eggs do (however, refrigeration can still extend their shelf life.)

Washing backyard eggs

Should consumers who harvest their own eggs from backyard hens wash their own eggs?

“Interestingly, the United States Department of Agriculture says ‘no’. The USDA reasons that only by using large-scale manufacturing equipment can eggs be properly sanitized without exposing them to other bacteria. Egg processors have mastered the process of washing eggs at precisely the right temperature to kill salmonella without cooking the egg, as well as transporting and storing them without exposing them to pathogens. Consumers are advised against washing their own chickens’ eggs as this may inadvertently force water and bacteria into the pores once the cuticle is removed.” ^[19]Fox, Tyler. Most of the world does not refrigerate their eggs.

Which approach is better? Washing or not washing eggs?

A 2018 peer-reviewed study, “Impact of egg handling and conditions during extended storage on egg quality” found that whether washed or unwashed, refrigeration had the biggest impact on quality and shelf-life of eggs.

“In her study, [Deana] Jones compared the quality of 5,400 eggs that were stored using the four primary egg-handling conditions found throughout the world: unwashed and refrigerated; unwashed and stored at room temperature (72 ˚F); washed and refrigerated (at 39 ˚F); and washed, coated with mineral oil, and refrigerated (egg processors will sometimes spray eggs with mineral oil or food oil to retain moisture and prevent bacteria from penetrating the shell). She used the same USDA standards used in commercial egg-processing plants to grade the eggs (grades AA, A, and B), and she weighed them each week for 15 weeks.” ^[20]O’Brien, Dennis. USDA Agricultural Research Service. How We Store Our Eggs—and Why. Accessed August 2020 at https://tellus.ars.usda.gov/stories/articles/how-we-store-our-eggs-and-why/

After 15 weeks, scores for all refrigerated treatments were still Grade A, while unwashed eggs stored at 22°C dropped from Grade AA to almost Grade B in one week alone:

“The results of this study indicate that refrigeration has the greatest impact on sustaining egg quality. The unwashed eggs held at room temperature experienced a rapid decline in all egg quality factors. The three refrigerated treatments (washed, washed and oiled, and unwashed) were similar in maintaining egg quality. The washed and oiled treatment did experience the lowest rate of cumulative weight loss (0.33 %) compared to the other three treatments. Washed and unwashed refrigerated eggs had cumulative weight loss of approximately 1.5 %, with unwashed room temperature eggs losing in excess of 15 % of egg weight over 15 weeks of storage.” ^[21]Jones, D.R., Ward, G.E., Regmi, P., Karcher, D.M. 2018. Impact of egg handling and conditions during extended storage on egg quality. Poultry Science. 97:716-723. Accessed August 2020 at https://www.ars.usda.gov/research/publications/publication/?seqNo115=345597

The issue of washed / unwashed and refrigerated / unrefrigerated shell eggs is one that constantly arises as a barrier in trade talks between the EU and the United States.

The response of most European consumers to the promise of extended quality for refrigerated eggs is that they typically don’t have them around the house for very long, anyway.

Purchasing eggs

Brown eggs. Jacqueline Macou / pixabay.com / 2016 / CC0 1.0

The industry trade term for eggs still in their shell is “shell eggs”.

The shell colour, white or brown, has no nutritional significance. White hens produce white eggs; brown or red hens produce brown eggs.

The darkness of the yolk does not indicate freshness or flavour. The darkness of the yolk depends, rather, on what the birds were fed, and what breed they are.

You may have noticed that supermarket eggs are packed in their cartons with the larger end facing up. This helps to keep the yolk centred within them, making for more appealing boiled eggs with the yolk right in the middle.

Buying eggs that have been washed during processing

All U.S. Extension Systems recommend against buying unrefrigerated eggs in the United States for safety reasons. This is because the eggs have been washed, and after washing require refrigeration. (Note this may not apply to eggs purchased at the farm gate, which may be unwashed).

The University of Maine Extension Service says,

“Buy eggs from a refrigerated display case. If the trip home will take more than 30 minutes or if it is a very hot day, put the eggs in a portable cooler for the trip, if possible. Cold temperatures help maintain quality by slowing the loss of moisture and carbon dioxide from the eggs. The cold also slows the growth of any bacteria that might be present. Retail sales of eggs and the use of refrigerated display cases are governed by state regulations.” ^[22]El-Begearmi, Mahmoud. Bulletin #2257, Food Safety Facts: Facts About Eggs. University of Maine Extension Cooperative Extension. 2002.

The Clemson Cooperative Extension says, “Buy clean eggs from a refrigerator display case. Do not purchase eggs anywhere that are not refrigerated.” ^[23]Schmutz, Pamela and E.H. Hoyle. Safe Handling of Eggs. Clemson University Extension Service. Factsheet HGIC 3507. 7 January 2007. Accessed August 2020 at https://hgic.clemson.edu/factsheet/safe-handling-of-eggs/

The University of Michigan Extension service says:

“Only buy eggs sold from a refrigerator or refrigerated case. Check eggs for cleanliness and cracks before buying. Store promptly in a refrigerator with temperatures 40 degree Fahrenheit (4 C) or below.” ^[24]McGarry, Joyce. Safe Storage of Eggs. University of Michigan Extension Service. 4 October 2017. Accessed August 2020 at https://www.canr.msu.edu/news/safe_storage_of_eggs

Buying unwashed eggs

Eggs that were not washed during processing have their shell cuticle intact, and therefore do not require refrigeration at the store. This is how most eggs in the world are sold.

Note that that food authorities even in these countries generally recommend storage below 20 C (68 F), even if not refrigerated, and suggest that ideally, the eggs would be stored under actual refrigeration when possible for the longest- storage life.

Unrefrigerated eggs in supermarket aisle. Colchester, Essex, England. © CooksInfo / 2020

Egg freshness

Whatever size of grade of egg you purchase, it’s worth noting that neither is any indication of an egg’s freshness or lack thereof.

“The grade of an egg indicates its quality only at the time of packaging. Although eggs remain edible for weeks, provided they are kept whole and chilled, deterioration starts at the moment an egg leaves the chicken. Both the yolk and the white become more alkaline: as carbon dioxide is lost through pores in the shell, carbonic acid decreases. In the white, the resulting rise in alkalinity makes the proteins less attractive to one another, causing the white to become runny. Similarly the proteins surrounding the yolk weaken. The net result is that when an aged egg is cracked open, the white spreads out and the yolk is less likely to stay intact.” ^[25]Joachim, David, Andrew Schloss and A. Philip Handel. The Science of Good Food. Toronto, Canada: Robert Rose. 2008. Page 202.

Despite the current trend to look down on eggs produced by today’s technologically controlled environments, and the nostalgia about chickens roaming backyards and laying eggs in places you had to hunt for, the city dweller has probably experienced a gain in egg freshness and quality over the course of the past 100 years. The eggs now have prompt gathering, inspection, and (in North America) refrigeration from the outset.

Though people in the United Kingdom generally don’t refrigerate their eggs, and supermarkets there in fact sell them on ordinary, unrefrigerated shelves, an unrefrigerated egg degrades as much in one day as an egg under refrigeration does in a week.

The egg shell is porous, and speeds aging. It is best to keep eggs refrigerated in their container to help keep in the moisture, rather than in the open racks built into most North American refrigerators, especially with refrigerators being the driest place in the house.

The albumen of an egg thins as it ages, and becomes clearer. This thinning results in eggs that are more likely to break in the pan. As an egg ages, losing carbon dioxide and moisture through its shell, the mass inside shrinks and the small air cell at the wide end of the shell therefore increases.

Delia Smith wrote about this air space:

“…the construction of an egg includes a space for the air to collect at the wide end, and it’s the amount of air in this space that determines the age and quality of the egg and how best to cook it. In newly laid eggs, the air pocket is hardly there, but as the days or weeks paces, more air gets in and the air pocket grows; at the same time, the moisture content of the egg begins to evaporate. ”   ^[26]Smith, Delia. How to Cook: Book One. Page 12.

Thus arises an age-old housewife test: place in water, and if the egg sinks quickly, it is fresh; the higher it floats in the water, the older it is. This simple test no doubt would have been important when you found an egg while walking through the backyard and needed to know whether it was still good for eating or not.

Smith gives more detail on this test:

“Place the egg in a tumbler of cold water: if it sinks to a completely horizontal position, it is very fresh; if it tilts up slightly or to a semi-horizontal position, it could be up to a week old; if it floats into a vertical position, then it is stale. The only reason this test would not work is if the egg had a hairline crack, which would allow more air in. That said, 99 per cent of the time the cook can do this simple test and know precisely how the egg will behave [when cooked].”

[Ed: note that her time estimates may be based on English unrefrigerated eggs.]

Delia Smith goes further to say that she feels the freshness (or lack thereof) of an egg should be a key determinant in how it is cooked:

“If you want to cook [an egg] perfectly it is vital to determine how old the egg is… You can see very clearly why you may have had problems in the past and why an egg needs to be fresh if you want to fry or poach it, because what you will get is a lovely, neat, rounded shape. Alas, a stale egg will spread itself more thinly and what you will end up with if you  are frying it is a very thin pancake with a yellow centre. If you put it into water to poach, it would probably disintegrate, with the yolk and white parting company. Separating eggs is yet another hazard if the eggs are too old, because initially the yolk is held inside a fairly tough, transparent membrane, but this weakens with age and so breaks more easily… What this all means is, yes, you can cook perfect eggs every time, as long as you know how old they are.” ^[27]Smith, Delia. How to Cook: Book One. Page 12 – 13.

Very fresh eggs, when hard boiled, are hard to peel; they are easier when they are about 3 days old (refrigerated.)

Buy brown eggs one shopping trip, and white the next. This helps you keep track of which eggs to use first.

Cooking Tips

Egg white coagulates between 60 to 65 C (140 to 150 F.) Both egg white and egg yolk set at 70 C (158 F.) Salmonella is killed instantly at 71 C (160 F.)

When boiling eggs, don’t actually boil them. Keep the water at a gentle simmer. Eggs turn black or green when overboiled because the egg white releases hydrogen sulfide gas. This reacts with the iron in the yolk, forming “iron sulfide”, and voilà, eggs with green rings inside them. Placing boiled eggs in cold water stops the reaction right away.

Don’t overboil sauces with egg in them, either. H.P. Pellaprat wrote,

“An egg will cook and set at a temperature much lower than boiling point, therefore sauces, soups, or other mixtures to which eggs have been added should be cooked slowly and kept below boiling point. If too high a temperature is reached, the egg sets quickly and unevenly in small hard lumps, and a curdled appearance results.” ^[28]Pellaprat, H.P. Modern French Culinary Art.  Page 267.

If you really want to make a clear broth or stock, or make a consommé without wasting the egg white normally used to clarify one, rinse egg shells, add to the broth and simmer for about 10 minutes. The shells will attract sediment in the broth or stock. Strain.

Egg shells can be composted. Or let them dry, whiz them in your blender to a fine powder, and sprinkle in your garden — roses particularly appreciate the calcium. Some say that crushed egg shells will deter slugs and squirrels in your garden, but research has shown that, sadly, this doesn’t actually work.

Eggs being used in baking. Marina Davydenko / Pixabay.com / 2020 / CC0 1.0

Raw eggs

Raw eggs are generally called for in recipes such as ice creams, royal icing, Caesar salad dressing, eggnog and mayonnaise.

There is some concern over using eggs raw these days owing to possible salmonella contamination. It was previously thought that contamination could come just from the shell, but it is now known that the hen can pass it straight into the inside of the egg itself.

Special concern needs to be taken especially if preparing food for pregnant women, seniors or young children.

In the U.S., pasteurized eggs are now available. You could also substitute powdered egg.

The University of South Dakota Extension Service has worked out the following safety methods to prepare raw egg in recipes calling for it, without having to sacrifice the recipes or change the nature of them. Following are core excerpts; the entire guidance can be accessed at Egg Safety with Holiday Foods (link valid as of August 2020.)

Raw whole eggs

This method can be used for raw or lightly cooked eggs that are called for by a variety of recipes including ice cream and eggnog.

“In a heavy saucepan, stir together the eggs and either sugar, water or other liquid from the recipe (at least ¼ cup sugar, liquid or a combination per egg). Cook over low heat, stirring constantly, until the egg mixture coats a metal spoon with a thin film or reaches 160° F (71 C). Immediately place the saucepan in ice water and stir until the egg mixture is cool. Proceed with the recipe.” ^[29]Meyer, Lavonne. Egg Safety with Holiday Foods. South Dakota State University Cooperative Extension. 19 December 2018. Accessed August 2020 at https://extension.sdstate.edu/egg-safety-holiday-foods

Raw egg yolks: pasteurizing at home

This prepares raw egg yolks to be safely used in recipes such as Caesar salad dressing, chiffons, chilled soufflés, Hollandaise sauce, mayonnaise, mousses, etc.

“In a heavy saucepan, stir together the egg yolks and liquid from the recipe (at least 2 tablespoons liquid per yolk). Cook over very low heat, stirring constantly, until the yolk mixture coats a metal spoon with a thin film, bubbles at the edges or reaches 160° F (71 C). Immediately place the saucepan in ice water and stir until the yolk mixture is cool. Proceed with the recipe.” ^[30]Meyer, Lavonne. Egg Safety with Holiday Foods.

Raw egg whites: pasteurizing at home

This preparation can be used for frosting recipes calling for raw egg white, such as Royal Icing and Seven-Minute Icing, as well as various chilled desserts.

“In a heavy saucepan, the top of a double boiler or a metal bowl placed over water in a saucepan, stir together the egg whites and sugar from the recipe (at least 2 tablespoons sugar per white), water (1 teaspoon per white) and cream of tartar (⅛ teaspoon per each 2 whites). Cook over low heat or simmering water, beating constantly with a portable mixer at low speed, until the whites reach 160° F (71 C). Pour into a large bowl. Beat on high speed until the whites stand in soft peaks. Proceed with the recipe.” ^[31]Meyer, Lavonne. Egg Safety with Holiday Foods.

Raw egg consumption in the UK

In the UK, the Food Standards Agency (FSA) says as of 2017 that people can “safely eat raw or lightly cooked eggs – provided they were produced under the British Lion code of practice – without risking their health.” ^[32]Smithers, Rebecca. Egg safety – we’ve cracked it, food watchdog tells Britons. Manchester: The Guardian. 11 October 2017. Accessed August 2020 at https://www.theguardian.com/lifeandstyle/2017/oct/11/egg-safety-weve-cracked-it-britons-told-by-food-watchdog

Eggs bearing the red British Lion stamp have come from hens vaccinated against salmonella.

“A report published by the Advisory Committee on the Microbiological Safety of Food (ACMSF) in July last year said the presence of salmonella in UK eggs had been “dramatically reduced” in recent years. This meant, it said, that the risks were now “very low” for eggs that carried the British Lion quality mark. More than 90% of UK eggs are produced under this scheme, recognisable by a familiar red stamp on the egg.”

But authors of the report emphasized that “the revised advice does not apply to severely immuno-compromised individuals who need medically supervised diets prescribed by health professionals”, nor does it apply to “eggs that do not carry the Lion mark, non-hen eggs and imported eggs from outside the UK.”

Substitutes

In making baked goods, you can substitute for 1 egg the following: ½ teaspoon baking powder plus 2 teaspoon butter or shortening plus 2 tablespoon flour plus 2 tablespoon liquid OR in cake, ½ teaspoon of baking soda plus 1 tablespoon of vinegar, added at the very end of mixing.

There are many commercial egg-replacement products on the market now. See their package directions for how to substitute. Sometimes, you may want to add a teaspoon of oil such as canola per every two eggs being replaced, as the egg substitute is generally very low in fat, which could make your recipe drier.

Nutrition

The nutritional advice about eggs seems to vary every few years.

At some point, we are given the all-clear to eat eggs with no worries: that cholesterol associations have been disproven. A food writer for the National Post in 2017 noted:

“A growing body of research, including a 2016 study published in the American Journal of Public Health, has indicated that the specific variety of cholesterol and saturated fat found in yolks, previously thought to be evil, is largely benign. Further research from Penn State University has also shown that the omega-3 fatty acids and concentrations of vitamin A and E found in pasture-raised yolks can actually be beneficial.” ^[33]McNeilly, Claudia. The best food is the most familiar: Why is everyone suddenly so obsessed with eggs? Toronto: National Post. 8 June 2017.

A few years later, the Harvard Health Blog noted the opposite: “Eggs are back in the news — again. A study from the March 2019 JAMA found that higher intakes of cholesterol and eggs were associated with a greater risk of cardiovascular disease (CVD) and death. The researchers reported that ingesting an additional 300 milligrams of cholesterol per day raised this risk, as did eating an average of three to four eggs per week.” ^[34]Gelsomin, Emily. Digesting the latest research on eggs. 3 July 2019. Accessed August 2020 at https://www.health.harvard.edu/blog/digesting-the-latest-research-on-eggs-2019070317179

Health headlines are often maddeningly contradictory because human diets are very complex things to study, analyse and generalize from. And as new research emerges, recommendations change and evolve. To find current health information on eggs, CooksInfo recommends that you identify reputable sources on the Internet, or ideally, consult your family physician.

What seems to be consistent over the past several decades is that the main nutritional concern with eggs is controlling for salmonella.

“[Salmonella] can pass from the cloaca (the rear opening of the hen), up the oviduct, and then to the ovary. An ovary infected with salmonella can produce eggs that contain the bacteria within the yolk. (American) egg producers are .. required to vaccinate their hens and prevent them from encountering other animals which may harbor salmonella, like rats. This combination has resulted in an incredibly low infection rate. Only 1-in-every-20,000 (U.S.) eggs contain salmonella these days.” ^[35]Fox, Tyler. Most of the world does not refrigerate their eggs.

Equivalents

1 cup eggs = 5 – 7 medium eggs = 5 large eggs
1 cup of egg whites = 8 to 10 medium eggs = 6 – 7 large eggs
1 cup of egg yolk = 12 – 14 medium eggs = 11 – 12 large eggs
1 cup egg, hard-cooked and chopped = 4 large eggs
1 large egg, hard-cooked and sliced = 6 slices
1 large egg, raw = 3 tablespoon raw egg
1 yolk = 1 ½ tablespoon yolk = 1 large yolk
1 egg white = 2 tablespoon egg white
1 large egg = 4 tablespoons (¼ cup) liquid egg substitute

Storage Hints

Store the eggs pointed egg down, so that the yolk remains centered: “Eggs should be stored pointed end down in a cool place away from strong smelling foods as these can taint the eggs.”  ^[36]Pellaprat, H.P. Modern French Culinary Art. Page 267.

H.P. Pellaprat, the co-founder of the Cordon Bleu cooking school, advised people to let refrigerated eggs warm a bit before using them: “[Eggs] may be stored in a refrigerator but remember to take them out and allow to reach room temperature some time before using them.” ^[37]Pellaprat, H.P. Modern French Culinary Art. Page 267.

You can store egg yolks from shelled eggs covered in the fridge for up to 5 days. For longer storage, freeze them for up to 4 months.

Refrigeration both keeps eggs safe, and extends their storage life. Refrigeration is an option in countries where eggs are sold unwashed; it is non-optional in countries where eggs are sold washed.

Storing eggs in the refrigerator

Refrigerating store-bought eggs is non-optional in countries such as the U.S., Canada, and Japan.

It is also non-optional in countries such as Australia, New Zealand, South Africa, and Sweden if you bought washed-eggs there. The New Zealand egg authority, “Eggs Incorporated”, wants consumers to refrigerate both washed and unwashed eggs: “Always buy shell eggs that are clean and keep them refrigerated at home.” ^[38]Buying & Storing Eggs. New Zealand Eggs. Accessed August 2020 at https://eggs.org.nz/buying-storing-eggs/). In Australia, producers will print storage recommendations on the carton: “Like all food products, eggs should be stored in accordance with the manufacturer’s directions. You’ll find these instructions printed on the egg carton. Most egg producers in Australia recommend that eggs are stored below 15 C.” ^[39]Should you store your eggs in the fridge or pantry? New Zealand Herald. 20 April 2017. Accessed August 2020 at https://www.nzherald.co.nz/lifestyle/news/article.cfm?c_id=6&objectid=11841691

The University of Minnesota Extension service says, “If there is any bacteria in the eggs, it will grow rapidly at room temperature.” ^[40]Burtness, Carol Ann; Kathy Brandt, and Suzanne Driessen. Handling eggs safely to prevent Salmonella. University of Minnessota Extension. Reviewed 2018. Accessed August 2020 at https://extension.umn.edu/preserving-and-preparing/handling-eggs-prevent-salmonella

Clemson University concurs that “Any bacteria present in the egg can grow quickly if stored at room temperature.” ^[41]Schmutz, Pamela and E.H. Hoyle. Safe Handling of Eggs.

As an added bonus, refrigeration greatly extends the shelf life of eggs. Texas A&M AgriLife Extension Service says, “There is a lot of discussion about room-temperature versus refrigeration. Eggs will naturally degrade more rapidly at room temperature. An egg stored at room temperature might be edible for only three weeks compared to 15 weeks if it’s refrigerated.” ^[42]Russell, Adam. Backyard eggs: Tips for cleaning and storing eggs. Agrilife Today. 16 July 2020. Accessed August 2020 at https://agrilifetoday.tamu.edu/2020/07/16/backyard-eggs-tips-for-cleaning-and-storing-eggs/

Eggs procured directly from farmers or backyard hens should be refrigerated as well:

“Eggs should be refrigerated as soon as possible. Refrigeration preserves quality and reduces the potential for bacterial growth… Eggs should be stored at or below 45 degrees (7 C).” ^[43]Russell, Adam. Backyard eggs: Tips for cleaning and storing eggs. Agrilife Today. 16 July 2020. Accessed August 2020 at https://agrilifetoday.tamu.edu/2020/07/16/backyard-eggs-tips-for-cleaning-and-storing-eggs/

The advice is not to wash store-bought eggs in countries where eggs are already washed, such as the U.S. and Canada:

Clemson University says:

“Do not wash eggs. Washing eggs could remove the protective mineral oil coating put on at the plant and could increase the potential for bacteria on the shell to enter the egg.” ^[44]Schmutz, Pamela and E.H. Hoyle. Safe Handling of Eggs.

The University of Minnesota says:

“Don’t wash eggs because you remove the protective mineral oil coating and increase the potential for bacteria on the shell to enter the egg.” ^[45]Burtness, Carol Ann et al. Handling eggs safely to prevent Salmonella.

Storing unwashed eggs out of the refrigerator

Most of the world does not refrigerate its eggs. They can do this because the eggs are unwashed, leaving the cuticle on the shell: “The many countries that do not refrigerate their eggs are able to do so because they maintain the cuticle.” ^[46]Fox, Tyler. Most of the world does not refrigerate their eggs.

Still the British Egg Industry Council recommends that ideally, eggs should be stored in the refrigerator:

“Store eggs at a constant temperature below 20°C – this maintains freshness and quality. The fridge is the best place to keep them in domestic kitchens.” ^[47]Egg Info. Egg storage and handling. Accessed August 2020 at https://www.egginfo.co.uk/egg-safety/storage-and-handling

It’s important to note that once you have refrigerated eggs for storage, it’s important to keep refrigerating them: for safety reasons, you should not change your mind later and start storing those previously-refrigerated eggs out of the refrigerator, regardless of whether the eggs are unwashed or washed, or of which country you are in

“Once eggs are refrigerated, they must stay that way until they are consumed. This is because a chilled egg left out at room temperature will begin to sweat, which may facilitate the movement of bacteria on the shell into the pores.” ^[48]Fox, Tyler. Most of the world does not refrigerate their eggs. So why does the US?

Freezing eggs

To freeze whole eggs, crack them, beat them lightly, pour into a container, then label the container before you freeze it as to how many eggs are in there. Use within a year for best quality (note: this is a quality issue, not a safety one.)

“To freeze whole eggs, beat yolks and whites together. Egg whites and yolks can also be frozen by themselves. Use frozen eggs within a year. If eggs freeze accidentally in their shells, keep them frozen until needed. Defrost them in refrigerator.” ^[49]Schmutz, Pamela and E.H. Hoyle. Safe Handling of Eggs.

Egg yolks frozen by themselves can be a bit gelatinous when you thaw them. To prevent this, mix in either ⅓ teaspoon salt or 1 ½ teaspoon sugar per 4 egg yolks. (You don’t need to worry about this when freezing whole eggs; the egg white will stop the yolk from becoming gelatinous.) Label the frozen egg package or container as either sweet or savoury, so that you know what to use them for. Don’t forget as well to note how many egg yolks are in there.

Frozen egg whites will take about 5 hours to thaw at room temperature.

Just to be totally clear; you never freeze eggs right in their shells. The results are undesirable quality-wise.

“When a raw egg [in its shell] freezes, its contents expand and may crack the shell. When thawed, an egg with an uncracked shell may be hard-cooked successfully, but other uses may be limited. Freezing causes the yolk to become thick and syrupy, so it will not flow like an unfrozen yolk and blend very well with the egg white or other ingredients.” ^[50]El-Begearmi, Mahmoud. Bulletin #2257, Food Safety Facts: Facts About Eggs.

History Notes

The domesticated chicken as we know it dates back to only about 3000 BC. Chickens were probably chosen as a fowl to domesticate because, while most birds while lay a certain number of eggs, chickens will keep laying until they accumulate a certain number of eggs.

The Romans used chicken eggs and left many recipes for them.

You couldn’t eat eggs during Lent, until it was over on Easter Sunday, because eggs were classed as “meat” by Church dietary laws.

You may you wonder what they did with the eggs that chickens laid during that time. Eggs don’t store for a long time, even with perfect refrigeration, and there was no point in solving the problem by killing the hens, as meat couldn’t be eaten, either, unless you made a point of eating all your chickens before Lent started.

The older breeds available back then wouldn’t have laid eggs in the winter anyway, in the first part of Lent, but they would have swung into high gear as spring and the end of Lent approached. Eggs could be preserved by pickling them, covering them in wax or a fat such as butter or lard, packing them in salt, or packing them in brine or water with lime in it. They could be dried, then used as a powder later.

Most countries that controlled the sale of eggs through “marketing boards” have done away with the controls (for instance, UK, 1971.) Canada may be the only country in the world left with one.

Language Notes

French Terms for eggs:

• Oeufs à la Coque (very soft-boiled)
• Oeufs Brouillés (scrambled)
• Oeufs Durs (hard-boiled)
• Oeufs Frits (fried)
• Oeufs Mollets (soft-boiled)
• Oeufs Pochés (poached)
• Oeufs sur le plat (baked)

During the Middle Ages, the French word for “yolk” was “moyeu” and the word for the white was “aubun”. ^[51]Lang, Jennifer Harvey, ed. Larousse Gastronomique. New York: Crown Publishers. English edition 1988. Page 405.

Sources

Bichell, Rae Ellen. Why The U.S. Chills Its Eggs And Most Of The World Doesn’t. National Public Radio. 11 September 2014. Accessed August 2020 at https://www.npr.org/sections/thesalt/2014/09/11/336330502/why-the-u-s-chills-its-eggs-and-most-of-the-world-doesnt

Erickson, Alexa. This Is the Reason Why North Americans Refrigerate Eggs and Europeans Don’t. Reader’s Digest. Accessed August 2020 at https://www.readersdigest.ca/food/healthy-food/why-europeans-dont-refrigerate-eggs/

Prince, Rose. Savvy shopper: Eggs. Daily Telegraph, London. 1 January 2005.

USDA. Shell Eggs From Farm to Table. Updated 4 November 2019. Accessed August 2020 at
https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/egg-products-preparation/shell-eggs-from-farm-to-table

USDA. Poultry Division. “United States Standards, Grades, and Weight Classes for Shell Eggs”. April 1995. Retrieved May 2004 from http://www.ams.usda.gov/poultry/pdfs/AMS-EggSt-1995.pdf

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• Quail Eggs
• Waxed Eggs