| Process Steps |
Main Objectives |
Method |
Machinery & Installation |
Changes brought about |
| Withering |
Partial dehydration of shoots (about 75 % moisture) to make them
leathery for rolling: chemical changes |
Exposure to air under natural or controlled conditions. |
Withering lofts/ drums/ tunnels/ troughs: continous withering
machine. |
Lowering of moisture to about 55 percent; increases in caffeine,
soluble sugars and amino acids; changes in proportion of organic acids and activity of
leaf enzymes. |
| Rolling |
Rapture and distortion of tea shoots to allow mixing of enzymes and
substrates |
Mechanical bruising, tearing, cutting, crushing, breaking and
twisting |
Crank Roller C.T.C Machines; Rotorvanc; Triturators; Barbora Leaf
Conditioner; Continous Leaf Roller |
Shoots cut and twisted; cellular constituents mixed; oxidative
changes set in |
| Fermentation |
Chemical changes
of leaf constituents by enzymatic oxidation |
Exposure ro air under controlled temperature (about 30 degree C)
and humidity |
Fermentaion floor/ tray/ trough/ drum; Continuous fermenter |
Colour changes from green to coppery; polyphenolic bodies oxidised
and condensed |
| Drying |
Stoppage of fermentation; dehydration to ensure keeping quality of
product |
Exposure to blast of hot air in a counter current dryer (Inlet: 80
- 100 degree C Exhaust: 50-55 degree C) |
Conventional Tea Dryer; Tocklai continuous dryer; Fluid bed dryer |
Moisture reduced to about 4%. Product attains characteristics
colour and appearance; some sugar is caramelised; polyphenols undergo epimerisation |
| Grading & Sorting |
Remove dust and
fibre & grading into 2 to 6 clean grades |
The leaf is put through Grade Shifter. |
Fibrex Pennvolt Sorting Machine |
Sizing of different grades
done. |
