Definition A staple of the traditional Chinese kitchen which consists of duck, chicken or quail eggs preserved in a mixture of alkaline clay, ash, salt, quicklime, and rice hulls for several weeks to months.
Comment During the process, the egg yolk is converted to a dark green-grey colour, acquires a creamy consistency and smells like sulphur and ammonia. The egg white becomes a dark brown, translucent jelly with a mild salty flavour. The transformation is effected by the alkaline material, which gradually raises the egg’s pH to around 9 or more during the curing process This chemical process breaks down some of the complex, flavourless proteins and fats, resulting in smaller flavourful compounds.
Toxicity Copper sulphate and lead oxide were used to accelerate the curing process but, given their toxicity, have been formally banned from use.
Synonyms Hundred-year egg, pidan, preserved egg, millennium egg, thousand-year egg, thousand-year-old egg
R Nuwer, smithsonianmag.com 18.06.2013