Boiled egg

Boiled eggsare typically from achicken, and are cooked with their shells unbroken, usually by immersion in boiling water.Hard-boiledorhard-cooked eggsare cooked so that theegg whiteandegg yolkboth solidify, whilesoft-boiled eggsmay leave the yolk, and sometimes the white, at least partially liquid and raw. Boiledeggsare a popularbreakfastfood around the world.
Besides a boiling water immersion, there are a few different methods to make boiled eggs. Eggs can also be cooked below the boiling temperature, i.e.coddling, or they can be steamed. Theegg timerwas named for commonly being used to time the boiling of eggs.
Eggs have a long history of use as a food source, following the history of thedomestic Chicken, and recipes that include boiled eggs have been recorded since the first known cookbook,De re coquinaria,in which at least one recipe calls for the use of preserved boiled eggs.Alexander Popeis recorded as having recommended the method of cooking eggs over the embers or ashes of an open fire.
The process of cooking an egg causes theproteinswithin the yolk and albumin todenatureand solidify, resulting in a solid egg white and yolk.Coagulation (denaturing) of egg white proteins begins in the 55–60 °C (131–140 °F) temperature range, and egg yolks thicken at the slightly higher temperature of 65 °C (149 °F), solidifying at 70 °C (158 °F). As such, the yolk of an egg will never solidify before the white, though in a boiled egg heat will take longer to reach the yolk through the albumin (compared to afried egg), making this doubly true.The process may be reversed through breaking the connections between the proteins, which has been demonstrated through the application of eithersodium borohydrideorvitamin C.
There are variations both in degree of cooking and in the method of how eggs are boiled, and a variety ofkitchen gadgetsfor eggs exist. These variations include:
Hard-boiled or hard-cookedeggs are boiled long enough for the yolk to solidify (about 10 minutes).They can be eaten warm or cold. Hard-boiled eggs are the basis for many dishes, such asegg salad,cobb saladandScotch eggs, and may be further prepared asdeviled eggs.
There are several techniques for hard-boiling an egg.One method is to bring water to a boil and cook for ten minutes.Another method is to bring the water to a boil, but then remove the pan from the heat and allow eggs to cook in the gradually cooling water.Over-cooking eggs will typically result in a thin greeniron(II) sulfidecoating on the yolk,though the coating has been reported as having little effect on flavor.This reaction occurs more rapidly in older eggs as the whites are more alkaline.Rinsingor immersing the egg in cold water after boiling is a common method of halting the cooking process to prevent this effect,and in commercial operations the discoloration is removed by immersing peeled eggs in a bath oforganic acidafter cooking.
Hard-boiled eggs are recommended by the United States Department of Agricultural Food Safety and Inspection Service to be used within two hours if kept at room temperature, or within a week if kept refrigerated and in the shell.Shelled hard-boiled eggs sold in bulk are pickled or sealed in an atmosphere of carbon dioxide and nitrogen for preservation.
Hard-boiled eggs are commonly sliced, particularly for use in sandwiches. For this purpose specializedegg slicersexist, to ease slicing and yield even slices.For consistent slice sizes in food service, several eggs may have their yolk and white separated and poured into a cylindrical mold for stepwise hard-boiling, to produce what is known as a "long egg" or an "egg loaf". Commercial long eggs are produced in Denmark by its inventorDanæg[da]and in Japan byKENKO Mayonnaise[ja]. The machine for producing long eggs was first introduced in 1974.In addition to being sliced, long eggs can also be used in their entirety ingala pies.
Haminados, braised eggs slowly cooked overnight, is a traditionalSephardic Jewishdish first documented in medieval Spain and now part ofIsraeli cuisine, where they are typically served on their own or as part of theShabbatstewchaminand other dishes.
While the traditionalegg timercounts to 3 minutes for cooking a soft-boiled egg,some how-to guides recommend longer cooking times ranging from fiveto six minutes.ChefHeston Blumenthal, after "relentless trials", published a recipe for "the perfect boiled egg", suggesting cooking the egg in water that starts cold and covers the egg by no more than a millimeter, removing the pan from the heat as soon as the water starts to bubble. After six minutes, the egg will be ready.
Soft-boiled eggs are not recommended by theFood and Drug Administrationfor people who may be susceptible tosalmonella, such as very young children, the elderly, and those with weakened immune systems.To avoid the issue of salmonella,eggs can be pasteurisedin shell at 57 °C for an hour and 15 minutes. The eggs can then be soft-boiled as normal.
Soft-boiled eggs are commonly served inegg cups, where the top of the egg is cut off with a knife, spoon, spring-loaded egg topper, or egg scissors, using anegg spoonto scoop the egg out. Other methods include breaking theeggshellby tapping gently around the top of the shell with a spoon.Soft-boiled eggs can be eaten withtoastcut into strips, which are then dipped into the runny yolk.  In the United Kingdom and Australia, these strips of toast are known as "soldiers".
In Southeast Asia, a variation of soft-boiled eggs known as half-boiled eggs are commonly eaten for breakfast.The major difference is that, instead of the egg being served in an egg cup, it is cracked into a bowl to which dark or light soy sauce or pepper are added. The egg is also cooked for 7 minutes, resulting in a runnier egg instead of the usual gelatin state and is commonly eaten withkaya toastandkopi.
Boiled eggs are also an ingredient in variousPhilippine dishes, such asembutidoandchicken galantina.Boiled or steamed duck eggs that have been incubated for several days are also eaten in the Philippines, Vietnam, Laos, Cambodia, and Thailand as the food known asbalut.
In Japan,marinated soft-boiled eggs(味付け玉子,ajitsuke tamago)are commonly served alongsideramen. The eggs are typically steeped in a mixture of soy sauce,mirin, and water after being boiled and peeled. This provides the egg a brownish color that would otherwise be absent from boiling and peeling the eggs alone. Once the eggs have finished steeping, they are usually served on top of the soup.A similar method of cooking soft-boiled eggs popular in Japan is that of the hot spring boiled egg(温泉玉子,onsen tamago), which is cooked at a constant temperature of 70 °C (158 °F) as is present in the volcanichot springsof Japan, producing an egg with solid yolk andsol-like white.
Boiled eggs often form part of larger, more elaborate dishes. For example, a boiled egg may garnish a bowl oframen(often first marinated insoy sauce), be baked into a pie such as atorta pasqualina[it],or be encased inaspic(similar to the French dish œufs en gelée, which features poached eggs). They may also be chopped and mixed with mayonnaise to formegg salad, or be deep-fried and then baked within a serving oflamprais.
Boiled eggs can vary widely in how easy it is to peel away the shells.  In general, the fresher an egg before boiling, the more difficult it is to separate the shell cleanly from the egg white.As a fresh egg ages, it gradually loses both moisture and carbon dioxide through pores in the shell; as a consequence, the contents of the egg shrink, it loses protein, and thepHof thealbumenbecomes morebasic.Albumen with higher pH (more basic) is less likely to stick to the egg shell, while pockets of air develop in eggs that have lost significant amounts of moisture, also making eggs easier to peel.
Keeping the cooked eggs soaked in water helps keep the membrane under the shell moist for easy peeling. Peeling the egg under cold running water is an effective method of removing the shell. Starting the cooking in hot water also makes the egg easier to peel.
It is often claimed that steaming eggs in apressure cookermakes them easier to peel.Double blind testinghas failed to show any advantage of pressure cooking over steaming, and has further shown that starting boiling in cold water is counterproductive. Shocking the eggs by rapidly cooling them helped, and cooling them in ice water for 15 minutes or longer gave more successful peeling. Shocking was also found to remove the dimple in the base of the egg caused by the air space.
There are severalfoodborne illnessesassociated with eggs,most if not all of which are caused bypathogenic bacteria.The harmful bacteria associated with eggs are mostly of thegenusSalmonella,but other harmful bacteria that can grow at refrigerated temperatures have been found in retail egg products, such asBacillus cereusandStaphylococcus aureus.Previous studies indicated that "the complete coagulation of [the] whole egg" was sufficient to destroySalmonellabacteria,but it is now known that the only factor in the inactivation or destruction of pathogenic bacteria in eggs istemperature.Boiling eggs at a temperature of at least 62 °C (144 °F) for 30 minutes has been shown to inactivateSalmonellabacteria,though theFood and Drug Administrationrecommends cooking at the higher temperature of 74 °C (165 °F).
Bulk hard-boiled eggs have been linked to disease outbreaks such as listeriaandS. aureusinfections, mainly from contamination and when eggs are not washed in the supply chain.