Chinese Preserved Egg (Pi Dan) Making

Hunan Province — legend dates it to the Ming Dynasty (1368–1644); actual origin likely 500+ years ago

Pi dan (century egg / thousand-year egg): duck or chicken eggs cured in a mixture of clay, ash, salt, quicklime, and rice husks for 3–6 weeks. The alkaline environment transforms the egg — white becomes translucent dark jelly, yolk becomes creamy green-grey. The result is an intensely savoury, slightly sulphurous condiment with umami depth far exceeding fresh eggs.

• Hakarl (Icelandic fermented shark — similarly intense transformation)
• Surströmming (Swedish fermented herring — similarly pungent)
• Strong blue cheese (comparable intensity level in Western context)

Intensely savoury, sulphurous, deeply umami with slight ammonia note — prized in Chinese cuisine for its complexity