Hundreds of years ago, a savoury idea – called the century egg – was hatched in rural China. As the story goes, a farmer found naturally preserved duck eggs in a muddy pool of water and slaked lime (a type of calcium hydroxide). After surviving a tasting, he set out to replicate them manually, resulting in a delicacy that would endure for centuries as a comfort food in Hong Kong, China and parts of Southeast Asia.

Though details of the century egg’s discovery are undocumented, scientists estimate that it dates back more than 500 years to the Ming Dynasty. And aside from some techniques used for large-scale production today, the egg preservation process has remained relatively unchanged.

To make the eggs, a vat is typically filled with a combination of strong black tea, lime, salt and freshly burned wood ashes, and is left to cool overnight. The next day, duck, quail or chicken eggs are added to the mixture, and they soak anywhere from seven weeks to five months – not for a century as the name implies.

Read the full story on BBC Travel.