Pinghu zaodan (fermented eggs). [Photo/WeChat account: gh_d6d29231a239]

Pinghu zaodan (fermented eggs), a traditional delicacy from Pinghu, a county-level city in Jiaxing, East China's Zhejiang province, are gaining renewed attention as local efforts link intangible cultural heritage with modern cultural tourism development.

With a history of more than 200 years, the soft-shelled eggs are known for their translucent texture and rich flavor. They were awarded a gold prize at the Panama–Pacific International Exposition and are recognized as a provincial-level intangible cultural heritage item as well as a time-honored Chinese brand.

The product originated from an accidental mix of duck eggs and fermented grain mash in the early Qing Dynasty (1644–1911). Over time, the technique evolved into a refined process that combines natural fermentation with manual craftsmanship. Production typically begins around Qingming Festival and takes five to six months, during which the eggs are soaked, fermented, and carefully processed.

A key step involves gently tapping the eggshell to create fine cracks without damaging the inner membrane, allowing the fermented mixture to penetrate and develop the signature taste. This technique is considered central to the product's quality.

In recent years, efforts have been made to preserve and modernize the craft. A cultural exhibition hall dedicated to the product opened in 2021, while a standardized production facility was established in 2023 and put into operation in 2025, enabling year-round manufacturing.