Century egg 583564 225350854 2008-07-13T06:15:27Z Noclevername 1546209 text link {{Refimprove|date=March 2008}} {{Chinese |pic = Century egg sliced open.jpeg| piccap=Century egg sliced open|c=[[wiktionary:皮|皮]][[wiktionary:蛋|蛋]]|c2=[[wiktionary:松|松]][[wiktionary:花|花]][[wiktionary:蛋|蛋]]|p=''pídàn''|p2=''sōnghuādàn''|j=''pei4 daan2''|j2=''cung4 faa1 daan2''|vie=hột vịt bách thảo|l=''leather/skin egg''|l2=''pine-patterned egg''|tha=ไข่เยี่ยวม้า<br>(khai-yiew-ma)}} '''Century egg''', also known as '''preserved egg''', '''hundred-year egg''', '''thousand-year egg''', and '''thousand-year-old egg''', is a [[Chinese cuisine]] ingredient made by preserving [[duck]], [[chicken]] or [[quail]] [[egg (food)|eggs]] in mixture of [[clay]], ash, [[salt]], [[Calcium oxide|lime]], and [[rice]] straw for several weeks to several months, depending on the method of processing. After the process is completed, the yolk becomes a dark green, cream-like substance with a strong odor of sulfur and ammonia, while the white becomes a dark brown, transparent jelly with little flavor or taste. The transforming agent in century egg is its [[alkaline]] material, which gradually raises the [[pH]] of egg from around 9 to 12 or more.<ref name="McGee117">{{cite book | last = McGee | first = Harold | authorlink = Harold McGee | title = On Food and Cooking: The Science and Lore of the Kitchen | publisher = Scribner | year = 2004 |isbn = 0-684-80001-2 | pages = p. 117}}</ref> This chemical process breaks down some of the complex, flavorless proteins and fats, which produces a variety of smaller flavorful compounds. Some eggs have patterns near the surface of the egg white that are likened to pine branches. ==Production== The origin of the method for creating century eggs likely came about through placing eggs in mud made from [[alkali]]ne clay and water in order to preserve eggs in times of plenty. {{Fact|date=March 2008}} The clay hardens around the egg and likely resulted in the curing and creation of century eggs instead of spoiled eggs. ===Traditional=== [[Image:Century egg.jpg|thumb|left|125px|Century egg]] The traditional method for producing century eggs is a development and improvement from the aforementioned primitive process. Instead of using just clay, a mixture of wood ash, [[quicklime]], and [[Sodium chloride|salt]] is included in the plastering mixture, thereby increasing the [[pH]] and [[sodium]] content of the clay mixture. This addition of natural alkaline compounds improved the odds of creating century eggs instead of spoilage and also increased the speed of the process. A recipe for creating century eggs through this process starts with the infusion of three pounds of [[tea]] in boiling water. To the tea, three pounds of [[quicklime]] (or seven pounds when the operation is performed in winter), nine pounds of sea-salt, and seven pounds of wood ash from burning [[oak]] is mixed together into a smooth paste. Each egg is then individually covered by hand, with gloves being worn to prevent the corrosive action of the lime on skin. Each egg is then rolled in a mass of rice chaff to keep the eggs from adhering to one another before they are placed in cloth-covered jars or tightly woven baskets. In about three months, the mud slowly dries and hardens into a crust, and then the eggs are ready for consumption. The recipe makes around 100 to 150 century eggs. <!-- Do we really need {{Fact|date=March 2008}} here? --> [[Image:Century egg snow flake.jpg|thumb|Century egg showing snow-flake-like patterns]] ===Modern=== [[Image:Century egg1.jpg|thumb|left|160px|Century egg coated in a caustic mixture of mud and rice husk]] Even though the traditional method is still widely practiced, modern understanding of the chemistry behind the formation of century eggs has led to many simplifications in the recipe. For instance soaking the eggs in a [[brine]] of [[Sodium chloride|salt]] and [[lye]] ([[Sodium hydroxide]] or [[Sodium carbonate]]) for 10 days followed by several weeks of aging while wrapped in plastic is said to achieve the same effect as the traditional method. This is true to the extent that egg curing in both new and traditional methods is accomplished by introducing alkali [[hydroxide]] ions and sodium into the egg. Although extremely poisonous, [[lead oxide]] is also known to increase the curing speed of century eggs and is thus added to the curing mixture by some century egg producers in [[China]], which is the world's largest producer of century eggs. [[Zinc]] oxide may be used as a replacement<ref>{{Citation | last = Chen | first = JrWei | last2=Su |first2=HouPin| title = A new process for preparing spots-free pidan. | journal =Journal of the Chinese Society of Animal Science| volume = 33| number=1 | pages = 79-88 | year=2004 |url = http://www.cababstractsplus.org/google/abstract.asp?AcNo=20043209714}}</ref> Although zinc is an essential micronutrient it can lead to a copper deficiency, so the zinc content should be checked for safety. <br clear="all"/> ==Use== [[Image:Arranged century egg on a plate.jpg|230px|thumb|Arranged century egg on a plate]] Century eggs can be eaten without further preparation, on their own as a side dish. As an [[hors d'œuvre]], the Cantonese wrap chunks of this egg with slices of pickled [[ginger|ginger root]] (sometimes sold on a stick as [[street food]]). A Shanghainese recipe mixes chopped century eggs with chilled [[tofu]]. In Taiwan it is popular to eat century eggs on top of cold [[tofu]] with [[katsuobushi]], [[soy sauce]], and [[sesame]] oil in a style similar to [[Japan]]ese [[Hiyayakko]]. A variation of this recipe common in northern China is to slice century eggs over chilled silken (soft) [[tofu]], adding liberal quantities of shredded young ginger and chopped spring onions as a topping, and then drizzling light soy sauce and sesame oil over the dish, to taste. They are also used in a dish called old-and-fresh eggs, where chopped century eggs are combined with (or used to top) an omelet made with fresh eggs. Some Chinese households cut them up into tiny cubes and cook them with rice porridge to create ''Century egg and Lean Pork congee'' ({{zh-cp|c=皮蛋瘦肉粥|p=pídàn shòuròu zhōu}}). [[Rice congee]], lean pork, and century egg are the main ingredients. Peeled century eggs are cut into quarters or eighths and simmered together with the seasoned marinated lean slivers of pork until both ingredients are cooked into the rice congee. Fried dough sticks known as [[youtiao]] are commonly eaten with century egg congee. On special events, like [[wedding banquets]] or birthday parties, a first course platter of sliced [[Char siu|barbecued pork]], [[pickled]] [[leek (vegetable)|baby leeks]], sliced [[abalone]], [[pickled]] [[Julienning|Julienned]] [[carrots]], [[pickled]] julienned [[daikon radish]], [[seasoned]] julienned [[jellyfish]], sliced [[pork]], [[brawn]] and the quartered century eggs is served. This is called a ''lahng-poon'' in [[Cantonese (linguistics)|Cantonese]], which simply means [[cold dish]]. A popular street food in Hong Kong consists of whole century eggs coated in fish meal, breaded, and deepfried, producing a snack analogous to the ubiquitous [[Scotch egg]] in the [[United Kingdom]]. {{Fact|date=April 2008}}<!-- DO NOT REMOVE this bit about breaded century eggs without first reading the relevant section of the Talk page --> == See also == *[[Balut]] *[[Soy egg]] *[[Tea egg]] *[[Salted duck egg]] ==References== {{Commons|Century egg}} {{cookbook|century egg}} ===Notes=== {{reflist}} ===Bibliography=== * Mabel Ho (1988) ''Chemistry Potpourri : Unlocking Chemistry through Investigations'', Singapore Science Centre <!-- what is this?? --> * H.C. Hou (Hou Xiangchuan), (1981) [http://www.unu.edu/unupress/food/8F032e/8F032E03.htm "Hunger and technology - Egg preservation in China"], ''The United Nations University Press Food and Nutrition Bulletin'' Chapter 3, 3(2), ISBN 92-808-0254-2 * Taiwan Livestock Research Institute and Philippine Council for Agriculture (2001) [http://www.fftc.agnet.org/library/pt/2001028/ Enhancing the Value of Eggs: How to Make Balut and Century Eggs] Retrieved [[March 24]] [[2007]]. [[Category:Chinese ingredients]] [[Category:Egg dishes]] [[da:Tusindårsæg]] [[de:Tausendjährige Eier]] [[es:Huevo centenario]] [[fr:Œuf de cent ans]] [[he:ביצת מאה השנים]] [[nl:Duizendjarig ei]] [[ja:皮蛋]] [[pt:Ovo centenário]] [[th:ไข่เยี่ยวม้า]] [[zh:松花蛋]]