Overview
* 3 main events in green tea processing: steaming, rolling, and drying.
* After being plucked, the leaves are heated to prevent oxidation
* Newly plucked leaves are steamed and dried at about 150-170 F
* The leaves are then rolled and dried many times
* The final products still retain the green color with only small % of moisture (<5%)
* Green tea that contains mostly buds and young leaves has the best quality.
Photo courtesy of Yomi 995
Green tea is produced in large quantity in China, Vietnam, Japan, and Taiwan. The purpose of green tea manufacturing is to yield un-oxidized tea leaves. In order to keep them from being oxidized, the leaves are not withered. Because of the leaves are not fermented, most of the natural antioxidants still remain in the tea. The purpose is to change color while keep the chemical structure of the leaves intact.
3 main events in processing
The 3 main events in green tea processing are steaming, rolling, and drying. These three processes must be controlled to cause changes in color while keeping the chemical structure of the leaves intact. After the leaves are picked, they are placed on bamboo trays over a fire. They must be steamed right away in the temperature of 160F to 170 F.
Heating the tea leaves at this temperature will destroy the enzymes that are responsible for oxidation of the leaves. After the steaming, the leaves are softened enough to roll without being broken. Then they are dried and then rolled and dried again.
These two processes are repeated many times until the leaves stay in their shapes. Since the leaves of green tea are not withered like black tea, most of the water in the fresh leaves remains until the final drying process. Repetition of rolling and drying make sure that every area of the leaves are dried thoroughly and reducing the risk of unwanted oxidation. If left unattended, the tea leaves would oxidize into oolong tea and then black tea.
The Final products
The final products of the tea leaves contain about 2-3 % of the initial moisture. The leaves are then categorized into grades. It’s worth repeating that the grades of green tea are backed up by quality and flavor of the tea. In contrast, the grades of black tea don’t reflect or indicate neither the quality nor the flavor of the tea. The green tea grades are different for different countries. For example, China has Young Hyson, Gun Power. Japan has Extra, Choicest, Fanning, and Dust, while India has Fine Hyson, Young Hyson, Twankay, and Dust.