. Oolong tea production requires high investment for the technology and because of this it is used by only a few owners in Chiang Rai province. The price of Oolong tea is higher compared to that of green and black tea. However, based on the chemical properties studied by the Tea Institute at Mae Fah Luang University, the levels of catechins in Chinese tea leaves are not particularly different from those in Assam tea leaves [2].