Moisture - A Menace to Tea During
- Storage / Gapping
- Blending / Packaging
Process of Tea Manufacturing
Tea leaves are highly moisture sensitive. They absorb moisture during blending, storage and packaging, resulting in loss of flavour and distortion of colour.
Withering prepares the juices in the leaf for the manufacture of tea
Withering involves two processes:
Biochemical process: during which starch is converted to sugar, and some of the proteins turn to amino acids
Physical wither: water is removed from the leaf, to reduce the moisture content from 80% to 68%
For best quality, an air temperature of a steady 25-30°C is ideal, beyond 35°C the quality falls as leaf is overheated. Moisture content of leaf can vary after withering-often it is more than variation in fresh leaf. Thus withering widens the standard deviation of moisture content instead of reducing it...this common problem is expensive and complicated to solve.
After withering, the tea goes through Fermentation and then drying which is done in a tea dryer. This brings moisture content of tea down to about 2-3%. The dried tea is then sorted out.
Storage / gapping...
After sorting, tea is stored on floor or in bins prior to packing. If the tea regains moisture during sorting/storage, then the tea is passed through dryer once again to take out regained moisture prior to packing. This phase is known as gapping. During this period, temperature has to be maintained inside the dryer in the range from 60°C to 70°C (compared to 80-105°C required in drying).
Proper storage during blending / packaging
Tea has a tendency to pick up moisture during the blending and packaging process and so leaves have to be stored in an environment where it does not pick moisture.
- No moisture addition to "made" tea
- No loss of bloom
- High return on investment
- Elimination of gapping process
- No loss of liquoring quality