Boiled egg
An egg (usually a chicken egg ) that has been cooked in its shell in boiling water or under steam, for example in an egg boiler , is called a boiled egg , sometimes also as a breakfast egg .
An egg that is boiled without a shell is known as a lost egg or a poached egg .
In catering and industrial food preparation is partially Stangenei used, by which the appearance is simulated of sliced boiled eggs.
Basics
| consistency | cooking time |
|---|---|
| soft | 3-5 minutes |
| very soft | 6–8 minutes |
| hard | 8-10 minutes |
Boiled eggs are divided into hard , soft and soft eggs depending on the cooking time . Hard and ultra-soft refers to the condition of the yolk , soft to the condition of the albumen . For hard-boiled eggs, depending on the egg size, a cooking time of around 8 to 10 minutes is required, for soft-boiled eggs a cooking time of around 6 to 8 minutes and for soft-boiled eggs a cooking time of around 3 to 5 minutes.
Cooking process
Eggs should be stored for about 14 days after laying. Only then have they reached their full aroma and are easier to peel after cooking. The age of the eggs can be determined not only by means of the laying day noted on the shell, but also by means of a simple test: Fresh (young) eggs perish when they are placed in water, only the air-filled end expands something. Older eggs stand vertically in the water because the air bubble has already grown larger. Old eggs float on the surface of the water.
Before the cooking process
Eggs are often pierced at the blunt end before cooking so that they do not burst when cooking. However, the effectiveness is controversial.
During the cooking process
The yolk coagulates at a temperature of 65 ° C, the egg white at 82.5 ° C. The water must therefore have a temperature of at least 82.5 ° C in order to cook eggs in it. The egg white does not coagulate completely at lower temperatures (→ onsen eggs ). The eggs should be carefully placed in the boiling water with a spoon so that the shell does not burst.
Adding salt or vinegar to the cooking water can reduce the leakage when the eggs burst by allowing them to coagulate more quickly.
End of the cooking process
The subsequent quenching with cold water serves to interrupt the cooking process in soft-boiled eggs, which would otherwise take up to three minutes.
Repelled eggs should be eaten quickly, because when deterred, bacteria get through the shell into the interior of the egg and multiply there. As a result, the shelf life at room temperature is limited to about two days, as the Swiss Federal Office of Public Health found out. The reason for this is that the otherwise sterile interior of the egg contracts due to the rapid cooling, and water, which is never completely sterile, is sucked in through the porous egg shell. Boiled eggs that were not quenched, on the other hand, were microbiologically harmless even after three months of storage at room temperature, but occasionally showed reductions (odor, color, water loss). A month is therefore recommended as the storage period.
Peelability
The fact that certain eggs are easier to peel depends on their age. With increasing storage time of the egg, more and more air gets inside through the egg shell, with water and carbon dioxide escaping from the egg. This process gradually loosens the cohesion of the outer shell, which is still attached to the shell, and the inner shell, which is permanently attached to the protein. This process also increases the pH of the egg from around 7 to 9.
Discoloration of the yolk
If the eggs are heated too much or too long, the yolk can turn green to brown-black on the outside, especially with older eggs. Directly involved in this are the cysteine units in the proteins of the albumen , which contain thiol groups . When heated, these are replaced by hydroxyl groups through a nucleophilic substitution . This creates a protein with a new serine unit with the release of hydrogen sulfide (H 2 S):
The hydrogen sulfide gas diffuses to the interface between egg white and egg yolk. The egg yolk contains the protein phosvitin , which contains a particularly large amount of the amino acid serine . The hydroxy groups bound in the protein are often esterified with phosphoric acid . This creates many anionic groups that bind almost all of the iron in the yolk. The iron is initially released through prolonged cooking.
So the egg yolk releases iron and the egg white releases hydrogen sulfide as it cooks. Both substances meet at the interface between egg white and egg yolk and combine in a chemical reaction to form iron sulfide .
This is particularly noticeable with industrially boiled eggs, as the longer cooking time kills possible pathogens (e.g. salmonella ) more reliably and the eggs can be kept longer. However, this deficiency is only visual - although iron sulfide is generally harmful to health, it does not pose any health risks in this concentration.
Silver cutlery
When boiled eggs come into contact with silver cutlery , the surface of the cutlery reacts to form silver sulfide . The taste changes and the silver turns black. Due to the formation of hydrogen sulfide, the boiled egg no longer tastes good, because hydrogen sulfide is a colorless gas that smells like rotten eggs.
(excerpt from a still life with a carnation )
distribution
Boiled eggs are mainly eaten in Europe and North America , but also in other parts of the western world .
Hard-boiled eggs are used in a wide variety of dishes and are usually eaten cold. The brightly painted or colored Easter eggs are known . But they can also be found in egg salad , in fork bites , on bread rolls or as a snack egg . An egg cutter can be used to process hard-boiled eggs . This allows the product to be divided into even slices (e.g. as a bread topping).
Soft-boiled and warm eggs have been known as food since ancient times; This is proven by egg cup finds from Roman antiquity. Eggs are likely to have been popular at all times as a valuable source of protein that is cheaper and easier to store and prepare than meat or fish. Since eating them is also less tiring than chewing meat or fish, eggs were also often used as food for the sick and convalescent (literary for example in Theodor Fontane's novel Der Stechlin ).
An instruction from Roman antiquity is controversial. Apicius ( De re coquinaria 7,19,3) suggests the spices pepper and lovage for the ovum apalum ; The dish is then supplemented with soaked pine nuts , honey , vinegar and liquams . It is not certain whether the ovum apalum really means a soft-boiled or a hard-boiled egg, but the preparation according to this recipe supposedly leads to an edible result in both cases.
The soft-boiled egg is particularly common as a breakfast egg in Central Europe and parts of Scandinavia and the Baltic States. If necessary, it is protected from cooling by an egg warmer , served in an egg cup and consumed with a teaspoon (or with a special egg spoon). Egg cups are usually designed to hold the blunt end of the egg. The egg is placed in the cup, cracked open with a spoon or decapitated with an egg cutter or knife and - usually lightly salted - spooned out. The opening of the egg on the blunt side seems less common. This creates a small plateau, which makes it easier to apply salt. In addition to these types of egg consumption, egg cups in which the apparently very soft boiled egg was placed horizontally were also common in Germany well into the 17th century. The contents of the ice cream were apparently dipped up with bread rather than spooned out.
Name of the egg ends
The southern German word Gupf (plural: Güpfe ) is related to summit and denotes a "rounded tip", a dome. Various dictionaries also mention the meaning "end of the egg". It remains unclear whether Gupf refers to the more blunt or the more pointed end of the egg or both ends. In dictionaries or in food culture, clarifying such questions definitely plays a role.
In some regions of Swabia, shortly before Easter, a custom called Spitzarschen takes place. Here the ends are referred to as "pointed" and "ass".
Differentiation between raw and boiled eggs
Various techniques exist to determine non-destructively whether a given egg is raw or has already been cooked.
In contrast to a raw egg, a boiled egg can be described as a rigid body . If we put it into rotation, then immediately the whole turns bushhammered egg mixture with the same angular velocity , and within the egg occur no frictional forces. As a result, the rotary movement is fluid and quick. In the raw egg, however, the gelatinous interior, which is not rigidly connected to the shell, initially remains at rest during rotation due to the inertia before it slowly moves in the direction of rotation. Due to the different angular speeds in the egg, friction losses occur and the rotary movement is much slower compared to the boiled egg. At the same time, if an raw egg is stopped for a short time, another rotation starts, as the movement of the inside is now transferred back to the shell. A boiled egg does not rotate again after the stop.
From a physical point of view, the moment of inertia of the cooked egg is much greater than that of the raw egg. This is clearly noticeable when the egg rotates around its own axis when it is held in the hand.
The boiled egg in literature and the performing arts
- In classic Sketch of Loriot entitled The Breakfast the dispute flares up in a couple about how long the egg because now cooked.
- In Jonathan Swift's novel Gulliver's Travels the issue comes to the "right" end of the ice to the tangible reason for war between the thickness senders and top Dern in Lilliput what subtle as a satire on to Swift's view, but vehemently discharged religious controversies of his time was intended. Based on the curiosity of this dispute, the byte order of the storage format of computers is also differentiated into big-endian (Dick-Ender) and little-endian (Spitz-Ender), since many computer enthusiasts have discussed the question of the correct order in a similarly controversial manner .
- Charles Dickens also puts the boiled egg in a “spiritual” context: the vicar in Oliver Twist receives a boiled egg at the weekend to strengthen himself for his strenuous preaching work; the orphan Oliver is graciously allowed to spoon out the tip. Here the egg becomes a symbol of the supremacy of the male head of the family.
- The breakfast egg appears in the same function in the novel House without Guardians by Heinrich Böll . Here the main young people in the lean post-war period discuss why fathers or “uncles” actually get an egg for breakfast, even if they don't contribute enough to the family's maintenance, and come to the (preliminary) conclusion: “All fathers [...] get a breakfast egg “- in contrast to the rest of the family.
- Even with Walter Kempowski if only the father is supplied with an egg or even the rest of the family without is that clear - - the egg explicitly connected to the morning appearance of the male head of the family is. Here, however, the egg yolk appears as a recurring comic detail of the autobiographical novels, which the father regularly runs over his fingers when he eats the egg.
- In Thomas Mann's novel Buddenbrooks , the soft-boiled egg is also part of the traditional breakfast of the middle-class family in the first circles and is of course available to all family members. Tony Buddenbrook, one of the main characters, is sitting at breakfast in two scenes that are decisive for her life: When Bendix Grünlich's marriage proposal is made known to her, she has just carefully grasped her hot breakfast egg with the napkin and then consumed it. The trigger for the divorce of this marriage, Grünlich's bankruptcy, is also revealed during breakfast; The choice of food made by the two spouses already makes it clear that no real partnership has emerged. While Tony stuck to her usual breakfast of bread and eggs, Grünlich has breakfast in English - which his wife finds both elegant and disgusting. Tony was not allowed to marry her first love, the medical student Moorten Schwarzkopf. In the first conversation between Tony and Moorten, the egg - but not explicitly the breakfast egg - played an important role; Tony asked here spontaneously about its nutritional value compared to meat.
Formula for the cooking time
Physicists, especially the Austrian physicist Werner Gruber , have investigated how long eggs have to be cooked approximately under different environmental conditions in order to achieve the desired degree of hardness in each case; the egg to be boiled is placed in already boiling water. Let
d be the diameter of the egg at the thickest point in the top view (if you look at the egg from the tip or the blunt side; so to speak at the "equator" of the egg) in millimeters, the natural logarithm
and let T x be the prevailing temperatures in degrees Celsius: T water : temperature of the boiling water [≈ 100 ° C]; T start : temperature of the egg at the beginning of the cooking process [refrigerator ≈ 4 ° C ... room temperature ≈ 20 ° C]; T inside : temperature of the boiled egg yolk in the desired state [soft ≈ 62 ° C ... hard ≈ 82 ° C],
this gives the time t in minutes after which the egg in the desired state can be removed from the boiling water:
Physicist Charles DH Williams came up with another formula. This formula does not use the diameter, but the weight of the egg in grams (M) as the basis. This makes it much easier to apply a formula to boiling eggs, as a kitchen scale, unlike a vernier caliper, can mostly be found in the kitchen. Let M be the weight of the egg in grams, the natural logarithm and let T x be the prevailing temperatures in degrees Celsius ( T water : temperature of the boiling water [≈ 100 ° C at 0 meters above sea level]; T start : temperature of the ice at the beginning of the cooking process [refrigerator ≈ 4 ° C ... room temperature ≈ 20 ° C]; T inside : temperature of the boiled egg yolk in the desired state), this gives the time t in minutes after which the egg can be removed from the boiling water in the desired state :
Please note with both formulas: The boiling point for water depends on the height above sea level: It drops by 1 ° C per 285 m. When the water temperature is below ≈ 62 ° C, it is no longer possible to prepare "boiled" eggs, as they no longer coagulate.
See also
- Egg dish
- Solei
- Timer ( "egg timer")
- Egg of Columbus
- Egg in culture
Web links
- Cooking eggs Tips and link to the recommendation of the Swiss Federal Office of Public Health
- Mathematics around the egg Scientific background of the University of Würzburg
- Calculate the cooking time of the egg
Individual evidence
- ↑ Cooking eggs - traditionally, professionally, also in the microwave, tips & tricks . Kirchenweb.at. Retrieved May 17, 2012.
- ↑ a b Werner Gruber , Die Genussformel, Satzweiss Verlag, 2008, ISBN 3711050530 .
- ↑ right ? Don't eggs pop easily if you prick them before cooking?
- ↑ Interesting facts about the egg and scientific experiments (pdf; 284 kB) Villach, Austria: Peraugymnasium. Retrieved May 17, 2012.
- ↑ deterring eggs: yes or no? . Student portal FH Frankfurt (Main). Retrieved on May 17, 2012. ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ Department of Food Science: Shelf life of hard-boiled shell eggs under different storage conditions. Archived from the original on May 15, 2012. Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. In: Switzerland: Federal Office of Public Health (Ed.): Bulletin . 12, March 18, 2002, pp. 220-223. Retrieved February 23, 2012.
- ↑ Hard-boiled eggs . Food News. Retrieved May 17, 2012.
- ^ A b Klaus Roth: Boiled Eggs: Soft and Hard - Part2 . In: ChemViews . 2012, ISSN 2190-3735 . doi : 10.1002 / chemv.201200034 . ( Freely accessible English translation by Klaus Roth: Allerlei vom Frühstücksei. An Oological-Chemical Easter Contemplation . In: Chemistry in Our Time . 43, No. 2, 2009, ISSN 0009-2851 , pp. 100–114. doi : 10.1002 / ciuz .200900485 . )
- ↑ Shock for the egg . The time. Retrieved May 17, 2012.
- ↑ Roth, K. (2010): Chemical delicacies . 1st edition, Weinheim: Wiley-VCH. P. 34.
- ↑ Why do hard-boiled eggs sometimes have green yolks? . know.de. Archived from the original on December 1, 2011. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved May 17, 2012.
- ↑ Egg Spoon - The special spoon for boiled eggs
- ^ For example, in the Duden (1991 edition) it says "blunt part of the egg". In Wahrig (1997) it says: "Peak, peak (e.g. of the egg)", which seems to speak for the pointed end. The statement in Duden online "[upper] rounded part of something" is also unclear: "rounded part" applies to both ends, "upper" especially to the pointed end, because it points upwards in the egg cup, for example.
- ↑ Jonathan Swift: Chapter 4 - Of Dick-Enders and Spitz-Enders . In: Gullivers Reisen , Volume First Part - The Journey to Liliput. Jadukids,. Archived from the original on November 3, 2004 Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. .
- ↑ Werner Gruber's egg boiling formula .
- ↑ How long do you cook a 3-minute egg? An interesting approximation formula for egg boiling from physics.
- ^ Charles DH Williams: The Science of Boiling an Egg . University of Exeter. Retrieved May 17, 2012.
