After harvesting sencha leaves are rolled, dried naturally, and packed into large square blocks and wrapped in aluminum foil. They are then placed in boxes and stored in a refrigerated room at a temperature of 5 degrees Centigrade.
Humidity is controlled.
Teas stored in this manner remain remarkably fresh for a year or more. This storage method is uniformly employed by all harvesters of quality green teas in Japan. Gyokuro leaves are aged for 3 months after harvesting and are stored in a similar manner. After a tea is bagged for commercial use it will become stale in anywhere from 3 months to 1 year depending on the type and grade of the tea. We only bag our teas when we receive an order.