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Boiled egg

For eggs cooked without their shells in hot water, see poached egg. For other egg dishes, see list of egg dishes.

Boiled eggs are typically from a chicken, and are cooked with their shells unbroken, usually by immersion in boiling water. Hard-boiled or hard-cooked eggs are cooked so that the egg white and egg yolk both solidify, while soft-boiled eggs may leave the yolk, and sometimes the white, at least partially liquid and raw. Boiled eggs are a popular breakfast food around the world.

Boiled egg
A soft-boiled egg served in the half shell
Main ingredientsEggs (typically chicken)
VariationsBaked eggs, starting temperature, preparation
Food energy
(per 100 g serving)
136 kcal (569 kJ)
Nutritional value
(per 100 g serving)
Protein14 g
Fat9 g
Carbohydrate0 g

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. The egg timer was named for commonly being used to time the boiling of eggs.

History

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Eggs have a long history of use as a food source, following the history of the domestic Chicken, and recipes that include boiled eggs have been recorded since the first known cookbook, De re coquinaria,[1] in which at least one recipe calls for the use of preserved boiled eggs.[2] Alexander Pope is recorded as having recommended the method of cooking eggs over the embers or ashes of an open fire.[3]

Scientific background

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Boiled eggs, increasing in boiling time from left to right: 4 minutes, 7 minutes and 9 minutes

The process of cooking an egg causes the proteins within the yolk and albumin to denature and solidify, resulting in a solid egg white and yolk.[4] 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 a fried egg), making this doubly true.[3] The process may be reversed through breaking the connections between the proteins, which has been demonstrated through the application of either sodium borohydride or vitamin C.[5]

Variations

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There are variations both in degree of cooking and in the method of how eggs are boiled, and a variety of kitchen gadgets for eggs exist. These variations include:

Hard-boiled eggs

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Cross-section of a hard boiled egg
 
Overcooked egg showing green coating on yolk

Hard-boiled or hard-cooked[6] eggs are boiled long enough for the yolk to solidify (about 10 minutes).[7] They can be eaten warm or cold. Hard-boiled eggs are the basis for many dishes, such as egg salad, cobb salad and Scotch eggs, and may be further prepared as deviled eggs.

There are several techniques for hard-boiling an egg.[8] One method is to bring water to a boil and cook for ten minutes.[9] 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.[7] Over-cooking eggs will typically result in a thin green iron(II) sulfide coating on the yolk,[10] though the coating has been reported as having little effect on flavor.[5] This reaction occurs more rapidly in older eggs as the whites are more alkaline.[11] Rinsing[3] or immersing the egg in cold water after boiling is a common method of halting the cooking process to prevent this effect,[4] and in commercial operations the discoloration is removed by immersing peeled eggs in a bath of organic acid after cooking.[12]

 
Kuro-tamago, a variety of hard-boiled egg local to Ōwakudani in Kanagawa Prefecture, Japan. The eggs are boiled in the mineral-rich water of the valley's hot springs, resulting in the shells turning a characteristic black colour.

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.[13][14][15] Shelled hard-boiled eggs sold in bulk are pickled or sealed in an atmosphere of carbon dioxide and nitrogen for preservation.[1]

Hard-boiled eggs are commonly sliced, particularly for use in sandwiches. For this purpose specialized egg slicers exist, 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 inventor Danæg [da] and in Japan by KENKO Mayonnaise [ja]. The machine for producing long eggs was first introduced in 1974.[16] In addition to being sliced, long eggs can also be used in their entirety in gala pies.[17]

Haminados, braised eggs slowly cooked overnight, is a traditional Sephardic Jewish dish first documented in medieval Spain and now part of Israeli cuisine, where they are typically served on their own or as part of the Shabbat stew chamin and other dishes.[18][19]

Soft-boiled eggs

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"Softboiled" redirects here. For the 1923 film, see Soft Boiled. For the genre of crime fiction, see Cozy mystery.
See also: Shirred eggs

While the traditional egg timer counts to 3 minutes for cooking a soft-boiled egg,[20] some how-to guides recommend longer cooking times ranging from five[7] to six minutes.[21] Chef Heston 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.[22]

Soft-boiled eggs are not recommended by the Food and Drug Administration for people who may be susceptible to salmonella, such as very young children, the elderly, and those with weakened immune systems.[23] To avoid the issue of salmonella, eggs can be pasteurised in shell at 57 °C for an hour and 15 minutes. The eggs can then be soft-boiled as normal.[24]

Soft-boiled eggs are commonly served in egg cups, where the top of the egg is cut off with a knife, spoon, spring-loaded egg topper, or egg scissors, using an egg spoon to scoop the egg out. Other methods include breaking the eggshell by tapping gently around the top of the shell with a spoon.[25] Soft-boiled eggs can be eaten with toast cut into strips, which are then dipped into the runny yolk. In the United Kingdom and Australia, these strips of toast are known as "soldiers".[26]

In Southeast Asia, a variation of soft-boiled eggs known as half-boiled eggs are commonly eaten for breakfast.[27][28] 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 with kaya toast and kopi.[29][30]

Boiled eggs are also an ingredient in various Philippine dishes, such as embutido[31] and chicken galantina.[32] 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 as balut.[33]

In Japan, marinated soft-boiled eggs (味付け玉子, ajitsuke tamago) are commonly served alongside ramen. 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.[34][35] 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 volcanic hot springs of Japan, producing an egg with solid yolk and sol-like white.[1]

Other variations

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Piercing
Some pierce the shell beforehand with an egg piercer to prevent cracking, following recommendations first published by the Poultry and Egg National Board in 1966.[36] The American Egg Board currently recommends against this, as it can introduce bacteria and create hairline cracks in the shell through which bacteria can enter the egg.[note 1] A 1975 study showed increased cracking in pierced eggs compared to unpierced eggs.[37]
Steaming
Eggs can be taken straight from the refrigerator and placed in the steamer at full steam.[38]
Sous vide
Boiled eggs can be made by cooking/coddling in their shell "sous vide" in hot water at steady temperatures anywhere from 60 to 85 °C (140 to 185 °F). The outer egg white cooks at 75 °C (167 °F) and the yolk and the rest of the white sets from 60 to 65 °C (140 to 149 °F).[39][40]
Baked eggs
Eggs may be cooked to produce a result similar to boiling via baking in an oven by breaking eggs into a muffin tin or individual ramekins.[41]
Salted eggs
In China, eggs (particularly duck eggs) may be preserved by packing them in salt and charcoal or brine. The salted egg is then boiled or steamed prior to consumption. The process is related to century eggs, which are preserved for a long period and are not boiled.[42] The salting or pickling process in a typical salted egg takes 20—50 days.[1]

Dishes featuring boiled eggs

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A bowl of ramen topped with a seasoned boiled egg
 
An aspic with chicken and eggs
 
A jar of pickled boiled eggs

Boiled eggs often form part of larger, more elaborate dishes. For example, a boiled egg may garnish a bowl of ramen (often first marinated in soy sauce), be baked into a pie such as a torta pasqualina [it],[43] or be encased in aspic (similar to the French dish œufs en gelée, which features poached eggs[44]). They may also be chopped and mixed with mayonnaise to form egg salad, or be deep-fried and then baked within a serving of lamprais.[45]

Peeling

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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.[21] 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 the pH of the albumen becomes more basic.[3] 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.[46]

Keeping the cooked eggs soaked in water helps keep the membrane under the egg shell moisturized 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.[21]

It is often claimed that steaming eggs in a pressure cooker makes them easier to peel.[47] Double blind testing has 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.[21]

Safety

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There are several foodborne illnesses associated with eggs,[48] most if not all of which are caused by pathogenic bacteria.[49] The harmful bacteria associated with eggs are mostly of the genus Salmonella,[50] but other harmful bacteria that can grow at refrigerated temperatures have been found in retail egg products, such as Bacillus cereus and Staphylococcus aureus.[49] Previous studies indicated that "the complete coagulation of [the] whole egg" was sufficient to destroy Salmonella bacteria,[51] but it is now known that the only factor in the inactivation or destruction of pathogenic bacteria in eggs is temperature.[50] Boiling eggs at a temperature of at least 62 °C (144 °F) for 30 minutes has been shown to inactivate Salmonella bacteria,[50] though the Food and Drug Administration recommends cooking at the higher temperature of 74 °C (165 °F).[48]

Bulk hard-boiled eggs have been linked to disease outbreaks such as listeria[52] and S. aureus infections, mainly from contamination and when eggs are not washed in the supply chain.[49]

See also

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Notes

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  1. ^ The American Egg Board, an industry group, recommends against piercing shells on food safety grounds: "Piercing shells before cooking is not recommended. If not sterile, the piercer or needle can introduce bacteria into the egg. Also, piercing creates hairline cracks in the shell through which bacteria can enter after cooking.", Basic Hard-Cooked Eggs Archived 2 January 2010 at the Wayback Machine, American Egg Board

References

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  1. ^ a b c d Mine, Yoshinori; Guyonnet, Vincent; Hatta, Hajime; Nau, Françoise; Qiu, Ning (12 September 2023). "Traditional Egg and Egg Products". Handbook of Egg Science and Technology. CRC Press. pp. 259–280. ISBN 978-1-000-89961-0.
  2. ^ Kaufman, Cathy K. (2006). Cooking in ancient civilizations. Internet Archive. Westport, Conn. : Greenwood Press. pp. 96, 142. ISBN 978-0-313-33204-3.
  3. ^ a b c d Davidson, Alan (20 November 2014), Jaine, Tom (ed.), "egg", The Oxford Companion to Food, Oxford University Press, doi:10.1093/acref/9780199677337.001.0001, ISBN 978-0-19-967733-7, retrieved 25 September 2024
  4. ^ a b Sci Bytes (18 July 2018). "Why do eggs "hard-boil?"". Nature.
  5. ^ a b Toops 2014, p. 26.
  6. ^ Stadelman & Cotterill 1995, chpt. 17: Hard-Cooked Eggs.
  7. ^ a b c "How to Make Perfect Hard or Soft Boiled Eggs". What's Cooking America. 3 June 2015. Retrieved 25 September 2024.
  8. ^ Seehusen, Joachim (30 March 2021). "Oppskrift på perfekt kokt egg". Tu.no (in Norwegian). Teknisk Ukeblad. Archived from the original on 30 March 2021.
  9. ^ "How long to Boil Eggs". Eatbydate.com. 19 January 2012.
  10. ^ Belle Lowe (1937), "The Formation Of Ferrous Sulfide In Cooked Eggs", Experimental Cookery From The Chemical And Physical Standpoint, John Wiley & Sons
  11. ^ Harold McGee (2004), McGee on Food and Cooking, Hodder and Stoughton
  12. ^ Stadelman & Cotterill 1995, p. 469.
  13. ^ "Learn More About Eggs". Archived from the original on 22 August 2008. Retrieved 19 December 2006.
  14. ^ "Egg-ucation". Retrieved 19 December 2006. – suggests boiled eggs can be stored refrigerated for one week
  15. ^ "Shell Eggs from Farm to Table". Fact Sheets: Egg Products Preparation. United States Department of Agricultural Food Safety and Inspection Service. 20 April 2011. Archived from the original on 26 January 2013. Retrieved 12 January 2013. When shell eggs are hard cooked, the protective coating is washed away, leaving bare the pores in the shell for bacteria to enter and contaminate it. Hard-cooked eggs should be refrigerated within 2 hours of cooking and used within a week.
  16. ^ Pollack, Hilary; Sen, Mayukh (22 January 2018). "I Am Mystified and Horrified By the Long Egg". Munchies. Retrieved 28 April 2019.
  17. ^ "Call For Submissions: The Long Egg". FreakyTrigger. 18 August 2006.
  18. ^ Jawhara Piñer, Hélène (2021). Sephardi: Cooking the History. Recipes of the Jews of Spain and the Diaspora, from the 13th Century to Today. Cherry Orchard Books. p. 36. ISBN 978-1644695319.
  19. ^ "The Long History of Huevos Haminados, Slow-Cooked Sephardi Eggs | The Nosher". My Jewish Learning. 28 July 2020. Retrieved 12 August 2024.
  20. ^ Herbst, Sharon Tyler (2001). The New Food Lover's Companion. Barron's Educational Series. ISBN 0-7641-1258-9.
  21. ^ a b c d López-Alt, J. Kenji (30 September 2023). "The Food Lab: The Hard Truth About Boiled Eggs". Serious Eats. Retrieved 25 September 2024.
  22. ^ Blumenthal, Heston (12 November 2014). "Series: The Do Something expert Index How to boil an egg, the Heston Blumenthal way". The Guardian. Retrieved 12 November 2014.
  23. ^ "Plan Under Way to Help Lessen Risks from Contaminated Eggs". FDA Consumer magazine. Archived from the original on 11 March 2007. Retrieved 19 December 2006.
  24. ^ Schuman, J.D.; Sheldon, B.W.; Vandepopuliere, J.M.; Ball Jr, H.R. (2003). "Immersion heat treatments for inactivation of Salmonella enteritidis with intact eggs". Journal of Applied Microbiology. 83 (4): 438–444. doi:10.1046/j.1365-2672.1997.00253.x. PMID 9351225. S2CID 22582907.
  25. ^ "Fine Manners for Fine Dining". Retrieved 19 December 2006.
  26. ^ "Egg with Toast Soldiers". Archived from the original on 4 March 2010. Retrieved 22 April 2008.
  27. ^ Bakar, Baharom (7 December 2022). "Harga telur gred E separuh masak RM1.20 sebiji" [The price of half-cooked E grade eggs is now RM1.20 per egg]. Berita Harian (in Malay).
  28. ^ Azim Fitri Abd Aziz, Mohamad (17 January 2019). "Telur separuh masak, roti canai sarapan pilihan Al-Sultan Abdullah" [Half-boiled eggs, roti canai for Al-Sultan Abdullah's breakfast]. Berita Harian (in Malay).
  29. ^ Aris, Aim; Salim, Ahmad (14 December 2022). "Hainanese-style Kaya toast and half-boiled egg". SBS Food. Retrieved 27 September 2024.
  30. ^ "Traditional Breakfast of Kaya and Kopi". roots.sg. Retrieved 19 May 2020.
  31. ^ Lam, Francis (7 January 2015). "The Rich Tradition of Filipino Embutido". The New York Times. Retrieved 27 September 2024.
  32. ^ Bernardino, Minnie (13 March 1986). "Chicken Relleno: A Philippine Tradition". Los Angeles Times. Retrieved 27 September 2024.
  33. ^ Nys, Bain & Van Immerseel 2011, p. 497.
  34. ^ Ang, Catharina Y.W.; Liu, Keshun (1999). "Japanese Foods". Asian Foods : Science & Technology. Boca Raton: Technomic Pub. Co. p. 465. doi:10.1201/9781482278798. ISBN 9781566767361.
  35. ^ "Ajitsuke tamago". Immi Eats. Retrieved 24 July 2024.
  36. ^ Stadelman & Cotterill 1995, p. 386.
  37. ^ Maurer, A.J. (July 1975). "Hard-Cooking and Pickling Eggs as Teaching Aids". Poultry Science. 54 (4): 1019–1024. doi:10.3382/ps.0541019.
  38. ^ Bauer, Elsie. "How to Steam Hard Boiled Eggs". simplyrecipes.com.
  39. ^ "Important Cooking Temperatures". Edinformatics.com. 17 November 2006. Retrieved 11 June 2013.
  40. ^ Vega, César; Mercadé-Prieto, Ruben (2011). "Culinary Biophysics: On the Nature of the 6X°C Egg". Food Biophysics. 6 (1): 152–9. doi:10.1007/s11483-010-9200-1. S2CID 97933856.
  41. ^ Berolsheimer, Ruth, ed. (1941). 300 Ways to Serve Eggs. Chicago, Illinois: Consolidated Book Publishers. pp. 17–21.
  42. ^ Toops 2014, pp. 28–30.
  43. ^ "Giant Green Pie (Torta Pasqualina)". The New York Times. Retrieved 10 November 2019.
  44. ^ Beck, Simone; Bertholle, Louisette; Child, Julia (1964). Mastering The Art Of French Cooking. New York: Alfred A. Knopf. p. 547.
  45. ^ "The Lamprais Legacy". Sunday Observer. 7 January 2018. Retrieved 2 May 2021.
  46. ^ Brunning, Andy (26 March 2016). "The Chemistry of Eggs & Egg Shells". Compound Interest. Retrieved 25 September 2024.
  47. ^ Eggs Under Pressure Archived 10 August 2020 at the Wayback Machine By Mr. Brown. Published on 18 March 2016.
  48. ^ a b "What You Need to Know About Egg Safety". Human Foods Program. Food and Drug Administration. 5 March 2024.
  49. ^ a b c Van Immerseel, Nys & Bain 2011, pp. 15–22.
  50. ^ a b c Lopes, Stefani Machado; Fösch Batista, Ana Carolina; Tondo, Eduardo César (1 December 2018). "Salmonella survival during soft-cooked eggs processing by temperature-controlled water circulator". Food Control. 94: 249–253. doi:10.1016/j.foodcont.2018.07.028. ISSN 0956-7135.
  51. ^ Licciardello, J J; Nickerson, J T; Goldblith, S A (October 1965). "Destruction of Salmonellae in hard-boiled eggs". American Journal of Public Health and the Nation's Health. 55 (10): 1622–1628. doi:10.2105/AJPH.55.10.1622. ISSN 0002-9572. PMC 1256553. PMID 5890516.
  52. ^ "How should you react to the CDC warning about eggs?". Sanford Health News. 20 December 2019. Retrieved 23 September 2024.

Sources

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