During the clipper age, basically from 1840 to about 1870, the Great China Tea Run was one of the most anticipated and talked about events of the year. Great fortunes were wagered on the winner and the quality of the tea it would deliver. Back then, just like today, there was much debate about the medicinal qualities of tea.
The tea used for yak butter tea most probably comes from the mountains just west of Yunnan and Sichuan. What I have seen is a dark, formidable leaf with an intense flavor bordering on bitterness and smoke. Every Tibetan I have ever met, drinks it continuously and urges onto everyone whom he might meet.
As the name makes clear, tea and horses were the major commodities traded along this route from the Tang to the late Qing Dynasties, from around 600 AD to the 20th century. Trade and travel definitely took place along this route for several thousands of years before the Tang, as archaeological sites in Tibet and in the city of Chengdu demonstrate, but for us, this period is the most significant.
In China, the most commonly enjoyed tea is definitely green tea. Greens are easy to process, easy to store, and easy to brew – and they have the added benefits of tasting good and improving your health. Also, green tea is a good base for blends with flowers like jasmine, chrysanthemum and osmanthus.