Century Egg

皮蛋 · 松花蛋

What century egg is · a chemically transformed duck egg

Stop 1/8

皮蛋是什么 · 一枚被化学改造的鸭蛋

Century egg (preserved egg, pidan) is a duck egg transformed by alkali curing: a solution of sodium hydroxide (NaOH), salt and tea soaks the eggs for weeks to months until the white becomes a dark translucent gel and the yolk turns ink-green to ochre, often flowering with crystalline 'pine' patterns.

It is one of the most chemically expressive foods in Chinese cuisine — the process is reshaping protein with alkali, not adding preservatives. Century-egg congee, ginger century egg, and century-egg tofu are common uses.

The mechanism core is the curing chemistry — how alkali reshapes white and yolk (special-knowledge). The lead claim is handled only in debunking via mechanism: traditional mixes once used a lead-based metal source; modern mixes use copper or zinc for the same crystals and gel.

Nutritionally, century egg is built on the duck egg (~185 kcal, 12-13 g protein, 14 g fat per 100 g); curing hydrolyzes protein but total protein survives, while sodium rises clearly from the curing salt.

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Educational content, not medical advice — consult a clinician.

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Century Egg

皮蛋 · 松花蛋

What century egg is · a chemically transformed duck egg

Stop 1/8

皮蛋是什么 · 一枚被化学改造的鸭蛋

Century egg (preserved egg, pidan) is a duck egg transformed by alkali curing: a solution of sodium hydroxide (NaOH), salt and tea soaks the eggs for weeks to months until the white becomes a dark translucent gel and the yolk turns ink-green to ochre, often flowering with crystalline 'pine' patterns.

It is one of the most chemically expressive foods in Chinese cuisine — the process is reshaping protein with alkali, not adding preservatives. Century-egg congee, ginger century egg, and century-egg tofu are common uses.

The mechanism core is the curing chemistry — how alkali reshapes white and yolk (special-knowledge). The lead claim is handled only in debunking via mechanism: traditional mixes once used a lead-based metal source; modern mixes use copper or zinc for the same crystals and gel.

Nutritionally, century egg is built on the duck egg (~185 kcal, 12-13 g protein, 14 g fat per 100 g); curing hydrolyzes protein but total protein survives, while sodium rises clearly from the curing salt.

Read story

Educational content, not medical advice — consult a clinician.