All About the Egg

Calcium

The major role of the mineral calcium is in building and maintaining bones and teeth. Calcium is also essential for many other body functions related to the blood, nerves and muscles. One large egg provides 28 milligrams (mg) of calcium, 2.6% of the Daily Reference Value (DRV) for calcium, most of which is in the yolk. An eggshell is composed largely of calcium carbonate (about 94%) along with small percentages of magnesium carbonate and calcium phosphate and, in total, contains about 2 grams of calcium.
– See Daily Value, Daily Reference Values (DRVs), Nutrient, Shell

Calories

The calorie count for eggs varies with size.
– See Nutrient, Reference Daily Intakes (RDIs)

Candling

The step in grading during which the egg grader looks inside the egg (without breaking it) to judge quality. Long ago, this quality check was done by holding a candle behind an egg. Some hand-candling, using electric equipment, is still used for spot-checking or for training egg graders, but today most eggs pass on rollers over high-intensity lights, which make the interior of the egg visible. The eggs are rotated so all parts are visible. The candler checks the size of the air cell and the distinctness of the yolk outline. Imperfections such as blood spots show up in candling. Very large packing plants may also use electronic blood and/or check detectors to sort and remove eggs exhibiting these defects.
– See Air Cell, Blood Spots, Grading

Carotenoids

Antioxidants
– See Xanthophylls, Lutein and Zeaxanthin

Carton Dates

Egg cartons from plants producing USDA-graded eggs must display a Julian date – the date the eggs were packed. Although not required, egg cartons may also carry an expiration (sell-by) date and/or a best-by (use-by) date. On USDA grade-shielded egg cartons, if an expiration date appears, it can be no more than 30 days after the pack date. It may be less through the choice of the packer or quantity purchaser, such as your local supermarket chain. On USDA grade-shielded egg cartons, if a best-by (use-by) date appears, it can be no more than 45 days after the pack date. Eggs that are not packed under USDA’s grading program must be labeled and coded in accordance with egg laws in the state where they are packed and/or sold. Most states require the use of a Julian date.
– See Julian Dates, Expiration Date

Cephalin

A phospholipid found in nerve tissues, including the white matter of the brain and spinal cord. One large egg contains 0.23 gram of cephalin.
– See Nutrient

Chalazae (kuh-LAY-zah)

Ropey strands of egg white which anchor the yolk in place in the center of the thick white. Chalazae are neither imperfections nor beginning embryos. The more prominent the chalazae, the fresher the egg. Chalazae don’t interfere with the cooking or beating of the white and you don’t need to remove them, although some cooks like to strain them from stirred custard.
– See Composition

Chantilly Meringue

– See Italian Meringue

Chinese Eggs

– See Preservation

Cholesterol

A fat-like substance found in every living cell in your body. Cholesterol is made in necessary amounts by your body and is stored in your body. Cholesterol is especially concentrated in your liver, kidney, adrenal glands and brain. Cholesterol insulates nerve fibers and must be available for your body to produce vitamin D. Cholesterol is also required for the structure of cell walls, is essential to the production of digestive juices and is the basic building block for many hormones. Cholesterol is essential for life.

While your body produces cholesterol, dietary sources also can contribute to blood cholesterol levels. Research shows that a diet high in saturated fat, trans-fatty acids and excess calories contributes to increased levels of cholesterol in your blood.

Dietary cholesterol, found in all foods from animals, does not automatically raise your blood cholesterol levels. Your body usually compensates for dietary cholesterol by synthesizing smaller amounts in the liver, by excreting more or by absorbing less.

Elevated blood cholesterol levels do increase the risk of heart disease. You should know your blood cholesterol 14 C levels and, if they are elevated, follow your doctor’s advice. In a blood cholesterol-lowering diet, research shows that the most important change you can make is to limit saturated fats and trans-fatty acids. Including fats – such as monounsaturated and polyunsaturated fats and omega-3 fatty acids – also may help improve blood cholesterol levels. A wealth of research has shown that eggs do not have a significant impact on blood cholesterol levels, so it’s not necessary to avoid egg yolks, as part of an overall healthful diet. You can use egg whites freely.

One large egg contains 186 milligrams (mg) of cholesterol. Regardless of the color of the eggs, the hen’s housing system, or whether the eggs are fertilized, the cholesterol content is the same unless the feed was altered, in which case a claim will appear on the carton. Cooking does not affect the cholesterol content of eggs.
– See Fat

Choline

Choline is essential for the normal functioning of all cells in your body and assures the structural development and signaling functions of cell membranes. Choline is made by your body but needed in larger amounts during pregnancy and lactation. When consumed during pregnancy, choline may be a key factor in the development of infants’ memory functions and, later in life, choline may improve memory capacity. Animal studies have shown that a mother’s insufficient choline production and intake during pregnancy can cause either defective memory or lower memory capabilities that last throughout life. Research shows that choline supplementation during fetal development enhances memory function. Egg yolks are an important source of choline (126 mg per large egg yolk) and provide 28% of a pregnant woman’s daily needs (450 mg).

Choux Pastry

– See Cream Puff

Cleaning

Washing eggs to remove any dirt or stains. In modern laying houses, eggs are gathered shortly after they’re laid and moved to automated washing equipment. Strict federal regulations specify the procedures and cleaning compounds that may be used. Today most eggs are cleaned in mechanical egg washers employing sprayers, brushes, detergent-sanitizers, rinses and driers. Only clean eggs go to the market.

In washing, the bloom is removed. About 10% of egg packers apply an edible mineral oil to replace it.
– See Bloom, Oiling, Production

Coddled Egg

1. An egg cooked in a coddler.
– See Cooking Equipment, Coddler

2. A less frequently used term for eggs cooked-in-the-shell for a very brief time.

Cold Storage

The practice of holding eggs in refrigerated warehouses. Commercial cold storage of eggs began in the U.S. in 1890. Because egg production was seasonal then, spring and summer eggs could be held in cold storage for release during periods of relative scarcity in autumn and winter. This practice helped avoid drastic price fluctuations.

Modern breeding and flock management have virtually eliminated seasonal differences in egg production so that cold storage is neither necessary nor practical. Thanks to rapid handling methods and efficient transportation, most eggs reach the supermarket warehouse within a few days of being laid.
– See Preservation, Storing

Color

Egg shell and yolk color may vary. Color has no relationship to egg quality, flavor, nutritive value, cooking characteristics or shell thickness.

Shell (Color)

Shell color comes from pigments in the outer layer of the shell and, in eggs from various commercial breeds, may range from white to deep brown. The breed of hen determines the color of the shell. Among commercial breeds, hens with white feathers and ear lobes lay white-shelled eggs; hens with red feathers and ear lobes lay brown eggs.

White eggs are most in demand among American buyers. In some parts of the country, however, particularly in New England, brown shells are preferred. Commercial brown-egg layers are hens derived from the Rhode Island Red, New Hampshire and Plymouth Rock breeds. Since brown-egg layers are slightly larger birds and require more food, brown eggs are usually more expensive than white.

White (Albumen)

Egg albumen in raw eggs is opalescent and doesn’t appear white until you beat or cook it.

Yolk

Yolk color depends on the hen’s diet. If a hen consumes plenty of yellow-orange plant pigments called xanthophylls, the xanthophylls will be deposited in the egg yolk. Hens fed mashes containing yellow corn or alfalfa meal lay eggs with medium-yellow yolks, while those eating wheat or barley yield lighter-colored yolks. A colorless diet, such as white cornmeal, produces almost colorless yolks. Natural yellow-orange substances, such as marigold petals, may be added to light-colored feeds to enhance yolk color. Artificial color additives are not permitted. Gold or lemon-colored yolks are the most common. Yolk pigments are relatively stable and are not lost or changed in cooking.

A green ring around hard-boiled egg yolks is the result of sulfur and iron compounds in the egg reacting at the surface of the yolk. The greenish color may occur when you cook eggs for too long or at too high a temperature or when there is a high amount of iron in the cooking water. Although the color may be unappealing, eggs with green rings are still wholesome and nutritious and have a normal flavor. The best ways to avoid greenish yolks are to use the proper cooking time and temperature and to rapidly cool the cooked eggs.
 – See Cooking Methods, Hard-Boiled

Sometimes a large batch of scrambled eggs turns green. Although not pretty, the color change is harmless. Just as in hard-boiled eggs, the green color is the result of heat causing a chemical reaction between the eggs’ iron and sulfur. The green color occurs when you cook eggs at too high a temperature, hold them for too long, or both. To prevent the coloring, use stainless steel equipment and a low cooking temperature, cook the eggs in small batches and serve them as soon as possible after cooking. If it’s necessary to hold scrambled eggs for a short time before serving, it helps to avoid direct heat. Place a pan of hot water between the pan of eggs and the heat source.

Occasionally several concentric green rings appear in hard-boiled egg yolks. A yolk develops within the hen in rings. As the rings are formed, iron in the hen’s feed or water may cause the green coloring.

Complete Protein

- See Protein

Composition

Cooking Equipment

It’s easy to cook eggs with no special kitchen equipment. For example, you don’t need to have a double boiler to cook egg sauces and custards. Simply use a heavy-gauge saucepan over low heat. However, there are some pieces of kitchen equipment designed especially for preparing eggs. Some of these items – such as an electric egg cooker – are limited to egg use only, while others – such as custard cups – come in handy for a variety of foods.

As a rule, on top of the range, cooking is more even in heavy-gauge pots and pans. Baking dishes and pans of the proper size are particularly important for items that rise, such as breads, cakes and soufflés.

Beaters

Cooks once had to rely on muscle power to whip eggs. They used an assortment of large and small, flat and balloon-shaped whisks, many of which are still available. Today, most cooks use an electric stand or hand mixer. Blenders and some food processors can whip up a whole egg, an egg yolk or a mixture but do not produce stiffly beaten egg whites.

Bowls

There has long been a great controversy about the merits, if any, of using a copper bowl to produce volume in beaten egg whites. The copper in the bowl reacts with the conalbumin of egg whites much like cream of tartar to stabilize egg-white foam. With the addition of cream of tartar, a stainless steel or glass bowl works just as well, is much less expensive and avoids the possibility of copper leaching into food.

Because they tend to absorb fat, plastic and wooden bowls aren’t suitable for beating egg whites. Any film or residue of fat will keep the whites from forming a stable foam.

The size and shape of a bowl is important. When you use an electric stand mixer, use the bowl that comes with the mixer. A deep bowl with enough room for expansion is best for an electric hand mixer. For hand-whipping with a balloon whisk, use a bowl that’s rounded at the bottom, at least 10 inches across the top and 5 to 6 inches deep.

Cooking Equipment Especially for Eggs

Coddler

A small cup made of porcelain, heatproof glass or pottery with a screw-on top. To use a coddler, break an egg or two into the cup, screw on the top and submerge the cup in simmering water until the egg is cooked. Eat the eggs directly from the coddler. You can also coddle eggs in a small jelly-size canning jar.

Cooker

An electric appliance which steam-cooks eggs in the shell. Most egg cookers also have inserts or cups for steam-poached eggs and some have a flat insert for cooking fried or scrambled eggs and omelets.

Crepe Pan

A shallow, slope-sided skillet, 6 to 8 inches in diameter. Crepe pans range from inexpensive, lightweight pans to sophisticated electric models, some of which cook the crepes on what appears to be the outside of the pan. You can make crepes in almost any small shallow pan with sloping sides, such as a small omelet pan.

Custard Cups

Small, deep, individual bowl-shaped dishes, with a capacity of 6 or 10 ounces, designed for oven use and perfect for baking eggs, individual custards or quiches.

Omelet Pan

A shallow, slope-sided nonstick skillet, usually 7 to 10 inches in diameter. A double omelet pan consists of 2 shallow rectangular or semicircular pans attached by hinges. Each pan has a handle.

Piercer

A sharp-pointed tool for gently pricking a very small hole in the large end of an eggshell before hard-boiling. Piercing may allow some air to escape and some water to seep into the egg during cooking, which may make peeling easier. However, piercing often produces hairline cracks in the shell, making the egg more vulnerable to bacteria. For this reason, piercing is not recommended. To make peeling hard-boiled eggs easier, use eggs that are 7 to 10 days old.

Poacher

A rack that holds cups, sized to fit one egg each, over simmering water, or a small colander-like form that holds an egg as it poaches in simmering water.

Quiche dish

A round, shallow, straight-sided ceramic dish, usually with scalloped edges, for oven use. Sometimes also called a flan or tart dish, a quiche dish is available in several sizes. You can also use a pie plate of the same size to bake a quiche.

Ring

A round band, with or without a handle, to hold a fried egg during cooking.

Separator

A small cup centered in a round frame made of plastic, metal or ceramic. The cup catches the yolk while slots around the frame let the white slip through to a container beneath the separator. You can also use a kitchen funnel to separate eggs.

Slicer

A device which cuts a hard-boiled egg into neat slices with one swift stroke. An egg slicer has an indented tray in which the egg rests and a cutting mechanism of parallel wires. To chop an egg, carefully rotate the sliced egg 90 degrees in the tray and cut through again. You can also chop eggs using a pastry blender in a bowl or with a sharp knife on a cutting board.

Soufflé dish

A deep, straight-sided dish designed for oven use. Soufflé dishes are available in various sizes and can serve as casserole dishes, too. You can also bake a soufflé in a straight-sided casserole or baking dish or an uncoated saucepan of the same size.

Wedger

A device which cuts a hard-boiled egg into 6 equal wedge-shaped parts. The wedger holds the egg upright as you pull wires over it to cut the wedges. When you draw down the wires only partway, you can open the egg to hold a stuffing or to resemble a flower.

Cooking Functions

Although eggs are widely known as breakfast entrees, they also serve in many other ways. In fact, the cooking properties of eggs are so varied that eggs have been called “the cement that holds together the castle of cuisine”.

Eggs bind ingredients in dishes such as meatloaves or crab cakes, leaven such baked high-rises as soufflés and sponge cakes andthicken custards and sauces.

Eggs emulsify mayonnaise, salad dressings and Hollandaise sauce and are frequently used to coat or glaze breads and cookies.

Eggs clarify soups and coffee and retard crystallization in boiled candies and frostings.

Eggs add color, flavor, moisture and nutrients to baked goods such as cakes. As a finishing touch, hard-boiled eggs often serve as a garnish.

For more in-depth information visit www.IncredibleEgg.org

Cooking Methods

The basic principle of egg cooking is to use a medium to low temperature and time carefully. When you cook eggs at too high a temperature or for too long at a low temperature, the whites shrink and become tough and rubbery and the yolks become tough and their surface may turn gray-green.

To kill bacteria and other microorganisms, the recommended guidance is to cook eggs until the whites are firm and the yolks thickened. Cook egg dishes to an internal temperature of 160°F (71°C). Pasteurized shell eggs are available on the market for those who prefer eggs not cooked to this level of doneness. There are five basic methods for cooking eggs.

Baked

Eggs baked in a dish in the oven, also known as shirred. Break and slip 2 eggs into a greased 10-ounce custard cup, shallow baking dish or ramekin. Spoon 1 tablespoon milk or half and half over the eggs. Bake in a preheated 325ºF (163°C) oven until the whites are completely set and the yolks begin to thicken but are not hard, about 10 to 12 minutes, depending on the number of servings you’re baking.

Hard-boiled/Hard-cooked

Fried

For Sunny-Side-Up Eggs: Heat a small amount of butter in nonstick skillet over medium-high heat until hot. Break eggs and slip into pan, one at a time. Immediately reduce heat to low. Cover pan and cook slowly until whites are completely set and yolks begin to thicken but are not hard, 5 to 6 minutes. Sprinkle with salt and pepper.

For Over-Easy or Over-Hard Eggs: Cook as for Sunny-Side-Up, but do not cover pan. When whites are completely set and yolks begin to thicken but are not hard, 5 to 6 minutes. Slide turner under each egg and carefully flip it over in pan. Cook second side to desired doneness, 30 seconds to 1 minute.

For Basted Eggs: Cook as for Sunny-Side-Up, but use 2 tablespoons butter and do not cover pan. Cook until edges turn white, about 1 minute. Begin basting eggs with butter from pan. Cover pan between bastings and continue cooking until whites are completely set and yolks begin to thicken but are not hard, 4 to 5 minutes.

For Steam-Basted Eggs: Cook as for Sunny-Side-Up, but use 1 teaspoon butter or a light coating of cooking spray. Cook until edges turn white, about 1 minute. Add 1 teaspoon water to pan. Cover pan tightly. Continue cooking until whites are completely set and yolks begin to thicken but are not hard, 4 to 5 minutes.

Cooking Terms

The following terms or phrases regularly occur in egg recipes.

Cook until knife inserted near center comes out clean. Baked custard mixtures are done when a metal knife inserted off center comes out clean. The very center still may not be quite done, but the heat retained in the mixture will continue to cook it after you remove it from the oven. Cooking longer may result in a curdled and/or weeping custard. Cooking less time may result in a thickened but not set custard.

Cook until just coats a metal spoon. For stirred custard mixtures, the eggs are cooked to the proper doneness when a thin film adheres to a metal spoon dipped into the custard. The point of coating a metal spoon is 20° to 30°F below boiling. Stirred custards should not boil. The finished product should be soft and thickened but not set. Stirred custards will thicken slightly after refrigeration.

Slightly beaten. Beat eggs with a fork or whisk just until the yolks and whites are blended.

Well beaten. Beat eggs with a mixer, blender, beater or whisk until they are light, frothy and evenly colored.

Thick and lemon-colored. Beat yolks with an electric mixer at high speed until they become a pastel yellow and form ribbons when you lift the beater or drop the yolks from a spoon, about 3 to 5 minutes. Although yolks can’t incorporate as much air as whites, this beating does create a foam and is important to airy concoctions such as sponge cakes.

Add a small amount of hot mixture to eggs/egg yolks. When you add eggs or egg yolks to a hot mixture all at once, they may begin to coagulate too rapidly and form lumps. So, stir a small amount of the hot mixture into the eggs to warm them and then stir the warmed eggs into the remaining hot mixture. This is called tempering.

Room temperature. Some recipes call for eggs to be at room temperature before you combine the eggs with a fat and sugar. Cold eggs could harden the fat in this type of recipe and the batter might become curdled. This could affect the texture of the finished product. To prevent the curdling, remove eggs from the refrigerator about 30 minutes before you use them or put them in a bowl of warm water for 10 to 15 minutes while you assemble other ingredients. For all other recipes, use eggs straight from the refrigerator.

The following cooking terms apply specifically to egg whites.

Separated. Fat inhibits the foaming of egg whites. Since egg yolks contain fat, recipes sometimes call for the yolks to be separated from the whites. Beating the whites separately allows them to reach their fullest possible volume. It’s easiest to separate the yolks and whites when the eggs are cold, but whites reach their fullest volume if you allow them to stand at room temperature for about 30 minutes before beating.

Many inexpensive egg separators are available. To separate eggs, tap the midpoint of the egg sharply with a table knife. Hold the egg over the bowl in which you want the whites and gently pull apart the shell halves. Let the yolk nestle into the cuplike center of the separator and the white will drop through the slots into the bowl beneath. You can use the same process with a funnel.

Drop one egg white at a time into a cup or small bowl and then transfer it to the mixing bowl before separating another egg. This avoids the possibility of yolk from the last egg you separated getting into several whites. Drop the yolk into another mixing bowl if you need it in the recipe, otherwise into a storage container.
– See Storing

Add cream of tartar. Egg whites beat to greater volume than most other foods, including whipping cream, but the air beaten into them can be lost quite easily. To make the foam more stable, add a stabilizing agent such as cream of tartar to the whites. Lemon juice works much the same way.
– See Cream of Tartar

Add sugar, 1 to 2 tablespoons at a time. When you make meringues and some cakes, you add sugar to beaten egg whites. Sugar serves to increase the stability of the foam. However, sugar can also retard the foaming of the whites and you must add it slowly so you don’t decrease the volume. Beat the whites until they just begin to get foamy, then slowly beat in the sugar.
– See Meringue

Stiff but not dry. Beat whites with a mixer, beater or whisk just until they no longer slip when the bowl is tilted. (A blender or food processor will not aerate them properly.) If you underbeat egg whites, the finished product may be heavier and less puffy than desired. If you overbeat egg whites, they may form clumps which are difficult to blend into other foods in the mixture and the finished product may lack volume.

Stiff peaks form. Stiff but not dry.

Soft peaks or piles softly. Whites that have been beaten until high in volume but have not reached the stiff peak stage. When you lift the beater, peaks will form and curl over slightly.

Gently folded. When you combine beaten egg whites with other heavier mixtures, handle carefully so you don’t lose the air you’ve beaten into the whites. It’s best to pour the beaten egg whites onto the heavier mixture. Then, using a spoon or rubber spatula, gradually combine the ingredients with a downward stroke into the bowl, followed by an across-up-and-over-the-mixture motion. Come up through the center of the mixture about every three strokes and rotate the bowl as you are folding. Fold just until there are no streaks remaining in the mixture. Don’t stir because this will force air out of the egg whites.

Copper Bowl

– See Cooking Equipment, Bowls

Crème Anglaise

– See Custard, Stirred

Crème Caramel

– See Custard, Baked

Cream of Tartar

An acid ingredient which stabilizes beaten egg whites. As a rule of thumb, use 1/8 teaspoon cream of tartar per egg white or 1 teaspoon per cup of egg whites. For meringues, use 1/8 teaspoon cream of tartar for each 2 egg whites.
– See Cooking Terms, Add Cream of Tartar

Cream Puff

A light, but rich, hollow pastry puff which you can fill with a sweet filling for dessert or with a savory one, such as egg or chicken salad, for a main dish. Called choux pastry (Pâte or choux) after the French word for cabbage, cream puffs come out of the oven looking like little cabbages. A high proportion of egg is necessary to form the cream puff structure. Egg yolk helps to emulsify the fat and egg whites are drying agents for crisp, dry puffs. Visit www.IncredibleEgg.org for a cream puff recipe.

Crepe

A light, thin, egg-rich pancake. The word is French, but the crepe is so versatile that it exists in many other languages, too. It’s a Russian blini, a Jewish blintz, a Chinese egg roll, a Greek krep or a Hungarian palacsinta. Depending on the filling, a crepe can be an appetizer, main dish or dessert.

Crepe batter should be the consistency of heavy cream. Letting the batter rest for an hour or so after mixing allows the flour to absorb moisture and gives the air bubbles time to dissipate so that the crepes you make don’t have tiny holes.

You can make crepes in advance. Stack, wrap and refrigerate them for a few days and reheat to serve. For longer storage, double wrap and freeze. Visit www.IncredibleEgg.org for a crepe recipe.

Curdling

Also known as syneresis or weeping. When you cook an egg mixture such as a custard sauce too rapidly or for too long, the protein becomes over-coagulated and separates from the liquid, leaving a mixture resembling fine curds and whey. If the curdling in a custard sauce hasn’t progressed too far, you may be able to reverse it if you remove the mixture from the heat and stir or beat vigorously.

To prevent syneresis or curdling in a custard sauce, use a low temperature, stir (if appropriate for the recipe), cook just until the custard tests done, and cool quickly by setting the pan in a bowl of ice or cold water and stirring for a few minutes.

The term curdling is usually used in connection with a stirred mixture such as custard sauce, while weeping or syneresis are more often used with reference to pie meringues or baked custards.
– See Meringue, Soft Meringue

Custard

A cooked mixture of eggs and milk with sugar and flavoring sometimes added. There are two basic kinds of custard – stirred and baked.

Stirred custard is also known as soft custard, custard sauce or erroneously, boiled custard. This custard is cooked on top of the range to a creamy, but pourable, consistency. You can cook the mixture in a double boiler over hot water or in a heavy saucepan over low heat. Serve stirred custard as a pudding or over cake or fruit. Visit www.IncredibleEgg.org for a vanilla custard sauce recipe.

Baked custard is cooked in a water bath in the oven and has a firm, but delicate, gel-like consistency. Serve a sweetened baked custard as a dessert in itself or as a base for toppings and sauces. A quiche or timbale is an unsweetened baked custard.

The usual proportions for a sweet custard are one egg and two tablespoons of sugar for each cup of milk. This is the minimum ratio of eggs to milk which will produce properly thickened custard. You may, though, use as many as four eggs and increase the sugar to four tablespoons. Increasing the sugar will make the custard less firm and lengthen the cooking time. Increasing the egg will make the custard firmer and shorten the cooking time. You can also substitute two egg yolks for one whole egg. Two egg whites will also thicken the custard as much as one whole egg, but the characteristic custard color and flavor will be missing. Visit www.IncredibleEgg.org for baked custard and quiche recipes.

Cuticle

– See Bloom