Tea manufacture is the process of transformation of freshly
plucked green tea leaves to black tea. The process itself
is long, requires much care, attention, control and a scientific
understanding of the complicated physical and chemical changes
in the leaf as the manufacture progresses. There are several
distinctive processes that take place in the manufacture of
black teas.
PLUCKING:
The green leaf is harvested on a regular basis at intervals
ranging from 5 days to 8 days from each field. The plucking
of the soft two leaves and the bud is generally undertaken
by well trained women, because of the agility of feminine
hands. The manufacture begins from the time the leaf is plucked
in the field, and to ensure it retains its freshness, the
leaf is sent to the factories from the fields three to four
times a day.
WITHERING:
No sooner it is received at the factory, the leaf is weighed
and spread on troughs. Withering, is a process, where conditioned
air is circulated between the leaves, initially to remove
any surface moisture and thereafter to concentrate and chemically
breakdown the tea juices. It takes 10 hours to 14 hours for
the physical and chemical changes to take place, and bring
the leaf to soft and rubbery condition suitable for the next
stage of manufacture.
ROLLING:
Is the process by which the leaf is twisted and the leaf cell
walls ruptured to bring the juices to the surface of the leaf.
The rolling machines have deep jacket, a pressure cap to apply
pressure on the leaf, and the table itself has battens and
a cone at the center to twist the leaf. There are also the
more modern “Rotorvane” machines, which also give the same
twisting and turning effect. This process takes about 20 to
30 minutes.
Thereafter to separate the twisted leaf from the untwisted,
and to reduce the heat build up, the rolled leaf is passed
over a roll breaker. This machine has meshes which separate
rolled leaf. The unrolled is put back into the rollers for
further rolling whilst the rolled leaf is fermented.
FERMENTATION:
Of the tea juices is an essential process in the manufacture
of black tea. Fermentation is the oxidization of the enzymes
in the juices, which bring out the flavour, strength and the
colour of the liquors and infusions. Fermentations is generally
carried out on glass or tiled tables.
As fermentation progresses there is a colour change of the
leaf from greenish to coppery brown. The degree of fermentation
is judged by the colour and aroma.
DRYING:
The primary objective of drying is the extraction of moisture
and the arresting of fermentation. The fermented leaf contains
from 45% to 50% moisture. The leaf is passed through driers,
which have circuits of trays with perforation, on which are
conveyed the fermented leaf.
The drying process takes about 20 to 25 minutes and the initial
temperature is about 120 Degrees F(50 Degrees C) and is finished
off at a temperature of 200 Degrees F (93 Degrees C) to 220
degrees F (105 Degrees C) . The moisture content of the teas
when drying is completed is approximately 2% to 3% and the
coppery brown fermented tea particles are now back.
GRADING
(SIFTING):
The fired teas after cooling are graded / sifted according
to size and shape, as the trade demands. The different grades
of tea are identified nomenclature. On completion of the grading,
teas are stored in airtight bins of boxes. The sifting is
carried out on a series of grading and cleaning machines,
which have several trays of different mesh sizes, to separate
the tea particles to the various grades of tea and to remove
the stalk and fibre.
PACKING
/ DESPATCHING:
Teas are very hygroscopic and rapidly absorb moisture. When
sufficient quantities of teas are collected, the are either
packed in plywood tea chests of multi-walled aluminum craft
paper lined pager sacks and despatched to the auctions or
packed into tea packs of various forms for direct export/distribution.
PLUCKING:
WITHERING:
ROLLING:
FERMENTATION:
DRYING:
GRADING
(SIFTING):
PACKING
/ DESPATCHING:
