As the local government has been engaging tea experts to revive the Zisun tea processing technique, which for centuries was preserved only in texts, Zheng began experimenting back in the 2000s, both restoring and improving traditional methods.

"Restoring the ancient processing methods is essential, but personally I got involved simply because I love tea and I like to try my hand at processing any kind," Zheng says.

He first searched for the purple leaves in the wild, roaming the hills with a bamboo basket and a hoe. Whenever he discovered a plant with the right leaves, he would dig it up and replant it in his own plantation. Despite these endeavors, he only managed to find 80 or so bushes.

It took Zheng eight years to find enough plants and research ancient texts, including The Classic of Tea, before he was able to successfully produce the compressed tea, all the while tweaking the traditional steaming-and-deoxidizing process.

In 2017, he was made a national-level inheritor of Zisun tea processing, and last year, traditional tea processing techniques and associated social practices in China were inscribed on UNESCO's Representative List of Intangible Cultural Heritage of Humanity, with Zisun tea included.