Japanese Green Tea is getting more and more popular nowadays. Japanese Green tea has a refreshing flavour and aroma, as well as great health benefits, these are actually closely related to how it is processed.
Japanese green tea is a non-fermented tea, which opposite to black tea. Japanese green tea is processed using steaming method. The processes are divided into few sub-processes.
Tea leaves are picked by hand or machine. Higher grade tea leaf is picked by hand, while lower grade by machine.
After plucking, tea leaves are kept in a special storage equipment with high humidity and cool air for few hours. This is to maintain the freshness of the tea leaves by locking the moisture and cool down the heat before going through the steaming process.
In order to stop the oxidation and fermentation process by enzymes, tea leaves are steamed. The steaming process preserve the greenish color of the tea leaf, and remove the astringency grassy aroma. The length of the steaming process is very critical which will determine the flavour, color and aroma of the final product. Longer steaming process (deep-steamed) will produce a less astringent tea leaf, but will also cause tea leaf easily broken during the rolling process. Tea leaf contains 75% water after this stage.
Sencha Steaming Duration and its characteristic
Tea leaves are then being cooled down rapidly to room temperature to avoid being spoiled. Then tea leaves are dried by hot air fan to remove the moisture in order to enhance the flavour and aroma. Tea leaf contains 50% of water after this stage.
The objective of this step is to break the cell of the tea leaves in order to soften it, and create a uniform moisture distribution.
Second rolling mainly is to reduce the moisture in the tea leaves. Tea leaf contains 30% of water after this stage.
Tea leaves are rolled in one direction to create needle shape (pressing and heating). Tea leaf now contains 13% of water after this stage.
Finally, tea leaves are dried with hot air to reduce the moisture in the tea leaves uniformly. Tea leaf contains 6% of water after this stage. The low content of water allow long term storage of tea leaves and enhance its flavour and aroma.
Tencha is used to make matcha, there is no rolling process after steaming, because tea leaves will then be grounded into powder and become matcha
Kamairicha is processed with pan-fried method instead of steaming, which similar to Chinese tea.