How does Taiwanese Oolong differ from mainland Chinese Oolong?
For example, the Taiwanese high mountain green oolongs vs. Green Tieguanyin. Are they different varietals? Or are the differences in environment and processing enough to cause the taste differences?
This is an interesting question that has become much more complex and relevant just within the last decade or so.
Historically, Taiwanese Oolongs are a direct offshoot of mainland Chinese Oolongs. However, modern trends in tea production and popular tea types from Taiwan have created more of a two-way exchange between the two tea producing regions.
In regards to Taiwan High Mountain Oolong vs. Green Tie Guan Yin: They are two different tea plant varietals, environment and processing are also significant factors.
Green Tie Guan Yin is a relatively recent innovation that was initiated and made popular as a result of the popularity of Taiwan High Mountain Oolong Tea. Taiwan's largest tea corporation, Ten Ren Teas, with sister companies in China and Taiwan began producing Green Tie Guan Yin in the fashion of Taiwan High Mountain Oolong using their tea farms on the mainland as well as in Taiwan. This was in response to the success and demand that Taiwan High Mountain Tea achieved in the 1980’s and 1990’s.
These greener style, more modern (vs. traditional) style oolongs are more suitable for large scale production and require less labor and attention in their processing. Basically, green oolongs are produced without the steps involving relatively complex oxidation and roasting methods. As a result, their quality is more directly determined by farm cultivation than processing, since the production methods involving hands-on labor and skill have been minimized.