Century Egg

The name is a myth — the century egg takes weeks or months to make, not a hundred years. The English name stuck, apparently picked up by early Western visitors who encountered the dark, gelid result and decided something so strange must have required extraordinary time. The Chinese name, pídàn (皮蛋, 'skin egg'), is more accurate: the white transforms into a dark, slightly rubbery gel, while the yolk becomes a softer grey-green paste with a rich, sulphurous complexity.

The curing process is alkaline. Traditionally, eggs are packed in a mixture of clay, ash, salt, quicklime, and rice husks and left for 90 to 120 days. The high pH breaks down the egg proteins — a process called alkaline denaturation — without heat. Commercial production now uses a sodium hydroxide solution bath that achieves the same result in a fraction of the time, typically 10 to 14 days. Both methods produce the same chemical outcome, though traditionalists claim the slow-clay version produces a more nuanced result.

The mythology around century eggs in Western contexts is extensive and largely wrong. They are not rotten, not buried in horse urine (a popular claim), and not remotely 100 years old. The smell — a faint hydrogen sulphide note from the sulphur-containing amino acids in the yolk — is much milder than the appearance suggests. The flavour is rich, savoury, and mildly alkaline, somewhere between a very mature hard-boiled egg and a creamy blue cheese in structural terms.

Eating contexts vary by region. In Cantonese cooking, century eggs appear sliced alongside fresh tofu dressed with sesame oil and soy — the temperature contrast and textural difference make the combination more interesting than either element alone. In congee (jook), cubed pídàn is a standard addition alongside pork, giving the porridge a dark, savoury counterpoint. As a cold appetiser at banquets, sliced century eggs are typically dressed with a vinegar-ginger dipping sauce, which cuts the alkaline quality effectively.

Duck eggs are the standard; quail eggs are a smaller-format alternative, often used in appetiser plates. Regions with strong preserved-food traditions — Jiangsu, Guangdong, Hunan — produce the most consumed quantities. The Songhua variant from Jiangsu shows characteristic snowflake patterns in the white, caused by the crystallisation of amino acids during curing, and is considered a premium subtype.