Workers prepare to bake Wojingtan hard cakes. [Photo provided to chinadaily.com.cn]

The 137-year-old Wojingtan hard cake in Daishan county, Zhoushan, East China's Zhejiang province, has become a hit again in recent years.

With a maximum 12-month shelf life and a refreshing flavor, glutinous rice-made Wojingtan hard cakes used to be especially popular among fishermen.

To revive the ancient flavor, 31-year-old Lin Jieyi, the fifth inheritor of Wojingtan hard cake preparation techniques, decided to improve the quality and packaging of his products.

Workers pack Wojingtan hard cakes. [Photo provided to chinadaily.com.cn]

He purchased modern equipment to phase out manual steaming and baking procedures and ensure the cake have more balanced coloring.

Lin has also introduced coarse cereal-made hard cakes to appeal to people on diets.

"We are now developing low-sugar and sugar-free hard cakes," said Lin, adding that these new products are expected to hit the market in about six months.

Mould for Wojingtan hard cakes. [Photo provided to chinadaily.com.cn]

In addition, Lin has increased investment in marketing in recent years to promote Wojingtan hard cakes in more surrounding cities, including Ningbo, Hangzhou, and Shanghai, and has begun marketing them via online platforms such as Taobao, Pinduoduo, and Douyin.