Black Tea - Manufacture

Manufacture

1. After the harvest, the leaves are first withered by blowing air on them.
2. Then black teas are processed in either of two ways, CTC (Crush, Tear, Curl) or orthodox. The CTC method produces leaves of fannings or dust grades that are commonly used in tea bags and are processed by machines. This method is efficient and effective for producing a better quality product from medium and lower quality leaves of consistently dark color. Orthodox processing is done either by machines or by hand. Hand processing is used for high quality teas. While the methods employed in orthodox processing differ by tea type, this style of processing results in the high quality loose tea sought by many connoisseurs. The tea leaves are allowed to completely oxidize.
   • Orthodox: The withered tea leaves are heavily rolled either by hand or mechanically through the use of a cylindrical rolling table or a rotovane. The rolling table consists of a ridged table-top moving in an eccentric manner to a large hopper of tea leaves, of which the leaves are pressed down onto the table-top. The process produces a mixture of whole and broken leaves, and particles which are then sorted, oxidized, and dried. The rotorvane (rotovane), created by Ian McTear in 1957 can be used to replicate the orthodox process. The rotovane consisted on an auger pushing withered tea leaves through a vane cylinder which crushes and evenly cuts the leaves, however the process is more recently superseded by the boruah continuous roller, which consists of a oscillating conical roller around the inside a ridged cylinder. The rotorvane can consistently duplicate broken orthodox processed black tea of even sized broken leaves, however it cannot produce whole leaf black tea. The broken leaves and particles from the orthodox method can feed into the CTC method for further processing into fanning or dust grade teas.
   • CTC: "Cut, tear, curl" or "Crush, tear, curl" black teas is a production method developed by William McKercher in 1930. It is consider by some as a significantly improved method of producing black tea to the orthodox through the mincing of wither tea leaves. The use of a rotovane to precut the withered tea is a common preprocessing method prior to feeding into the CTC CTC machines then further shred the leaves from the rotavane by processing them through several series of contra-rotation rotors with surfaces patterning that cut and tear the leaves to very fine particles.
3. Next, the leaves are oxidized under controlled temperature and humidity. (This process is also called "fermentation", which is a misnomer since no actual fermentation takes place.) The level of oxidation determines the quality of the tea. This can be done on the floor in batches or an a conveyor bed with air flow for proper oxidation and temperature control. Since oxidation begins at the rolling stage itself, the time between these stages is also a crucial factor in the quality of the tea however fast processing of the tea leaves through continuous methods can effectively make this a separate step.
4. Then the leaves are dried to arrest the oxidation process.
5. Finally, the leaves are sorted into grades according to their sizes (whole leaf, brokens, fannings and dust), usually with the use of sieves. The tea could be further sub-graded according to other criteria.

The tea is then ready for packaging.