Tea Manufactuing Process
CTC refers to the Crush Tear & Curl process where the withered green leaves are passed in-between two rollers rotating in opposite directions. There is complete maceration of the leaves thereby rupturing the cells.
Steps in CTC tea manufacture
- Green leaf sifting
- Grading and sorting
It is a procedure which brings about physical and chemical changes in the shoots to produce quality, apart from conditioning the flush for rolling by reducing weight and volume. The evaporation of moisture in the green leaf is brought about by blowing or moving air over it in the enclosed withering trough. The direction of air flow can be changed by a movable baffle plate either below or above the trough.
Green Leaf Sifting
Extraneous matter such as stones, sand or metal pieces may find their way in the leaves brought into the factory; if such materials are fed into the fine-tuned, continuous machines, the moving parts will be severely damaged. Similarly if the leaves were not fed evenly into these machines, they could become jammed or would not function efficiently. Hence green leaf sifting is essential prior to processing.
The rotor vane has been found to be ideal to pre-condition the leaf for CTC processing.
After preconditioning, the leaf is passed through three CTC machines arranged in tandem. The CTC machine essentially consists of two contra-rotating toothed rollers of equal diameters.
Fermentation is the process during which the Polyphenols in the tea leaf are oxidized in presence of the enzymes and subsequently condensed to form Colored compounds contributing to the quality attributes of tea. Fermentation starts immediately after cell rupture.
It reduces the moisture content of rolled and fermented leaves from 45-50% level to a 3% level in dried black tea. It also allows development of black tea aroma. Drying is physically achieved through fluidized bed drying.
Grading & Sorting
Sorting is the operation in which tea particles of the bulk are separated into various grades of different sizes and forms confirming to trade.
Teas are packed in airtight containers in order to prevent absorption of moisture, which is one of the main causes for loss of flavour during storage.
Distinguishing between quality of teas is possible by the human palate only - In the tasting procedure, pots and tasting cups are used ; 2.5 gm of tea is weighed into pots and water which has just come to the boil is poured over it. The pots are then covered with a lid and the tea is infused for 5 minutes. The liquor is then poured out into a cup and the tea is ready for tasting. The residue of the infused leaf of the cup is then strained into the lid of the pot.
The brew in the cup is then evaluated for its colour and evenness of the infusion, as also its nose, which is the index to the intrinsic value of the tea., the taster then takes a sip from the cup, rolls it in his mouth and spits it out. The taster's palate registers the taste - Flavour, Briskness, and Strength. The taster then evaluates the strained leaf residue in the pot's lid and any faults and flaws are then recorded and then the taster is ready with his judgement.