A century egg is a Chinese preserved egg—usually duck, sometimes chicken or quail—that’s been cured in a highly alkaline mixture for weeks or months until the white turns into a dark, translucent jelly and the yolk becomes creamy, dark green-grey, and very intense in flavor.

Quick Scoop: What is a century egg?

  • A century egg (皮蛋 pídàn), also called preserved egg, hundred-year egg, or thousand‑year egg, is a traditional Chinese delicacy.
  • Despite the dramatic name, it is not 100 years old; typical curing time ranges from a couple of weeks to a few months.

How it’s made

  • Eggs are coated and packed in an alkaline “mud” made from ingredients like clay, ash, salt, and quicklime, often with rice husks around each egg to keep them from sticking.
  • Over time, the alkalinity raises the egg’s pH to around 9–12, breaking down proteins and fats into smaller compounds that change the texture and create a strong, savory aroma and flavor.

Look, texture, and taste

  • The “white” turns dark brown to black and becomes a gelatinous, glassy jelly, while the yolk turns dark greenish‑grey with a soft, creamy, sometimes slightly oozing center.
  • The taste is rich, salty, and umami, often with a pungent aroma from compounds like ammonia and hydrogen sulfide; many people find it intense but very flavorful once they get used to it.

How people eat it

  • Century eggs are commonly sliced and served with pickled ginger, used in congee (rice porridge), or added to cold tofu and salads as a savory topping.
  • Online, especially in forum and reaction videos, they’re a recurring “food challenge” item, with some users calling them “rotten but classy” or “classic horror,” while fans insist they’re delicious and underrated.

History, culture, and “trending” angle

  • Most accounts trace century eggs back several centuries, likely to the Ming dynasty (14th–17th century), when alkaline clay preservation emerged as a way to store eggs long‑term.
  • Today they are a staple of Chinese cuisine and diaspora cooking, and they periodically trend in international food media and social platforms whenever someone posts a dramatic first‑time reaction or “what is a century egg” explainer.

TL;DR: A century egg is a Chinese preserved egg cured in alkaline clay until it turns dark, jelly‑like, and powerfully savory—strange to newcomers, but a classic delicacy for those who grow up with it.

Information gathered from public forums or data available on the internet and portrayed here.