In addition to exports, coffee beans grown in Pu'er are also bought directly by leading coffee houses Nestle and Starbucks. Nestle introduced high-yielding Arabica coffee trees to Pu'er in the late 1980s.

The Swiss company buys direct from around 1,100 suppliers in Yunnan, mainly based in Pu'er city and Xishuangbanna Dai autonomous prefecture. The price changes based on coffee futures, usually twice a week, according to Wouter De Smet, Nestle's coffee agricultural service manager in Pu'er.

Nestl bought 11,400 tons of beans last season and this will rise to 15,000 tons in 2015, one-fourth of Pu'er's total output. The company set up the Coffee Agricultural Service in Pu'er in 1992 to maximize the value of Yunnan's coffee production, in Pu'er in particular, and the value of crops by teaching farmers sustainable cultivation methods.

In April, the Nescafe Coffee Center was established as part of a cooperation agreement between Nestle and the Pu'er government to further provide training and infrastructure for farmers and to promote local coffee.

De Smet said his center provides free training for farmers, focusing on the process of growing coffee and improving quality. In the past two years, about 8,000 farmers in Pu'er have benefited from the courses.

"I have spent around half of my eight years in Pu'er in the fields and farmers' houses, so that I can better understand the plantation and quality issues," he said.

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From the tree to the cup