|
Technology Trends
in Tea Manufacturing
|
Tea plucked from the garden is sent to the factory
for processing, which in most cases, is in or near the tea garden.
This processing, earlier, used to depend solely on the natural weather
conditions, but to become less dependent on the unpredictable weather
conditions which affects productivity adversely, modern technology
has been introduced in the tea industry. This has made it possible
to increase the plantation area by minimizing space; also labour
cost has come down and the entire process has become much more speedy.
|
|
The
starting material in black tea processing is the young shoot, the
terminal bud and the two adjacent leaves plucked from the tea plant.
The flush is processed in four distinct stages, which are withering,
rolling, fermentation and drying. Each stage involves characteristic
changes in the physical and biochemical composition of the leaves
and the cumulative effect of these changes are ultimately reflected
in the quality of the finished product, namely the black tea. After
the drying is over, the leaves are sorted, that is, divided into
different grades and made ready for the market.
|
|
|
Plantations
:Unlike other
perrenials, tea is unique because only its vegetative parts
- the two leaves and the bud - are commercially exploited.
Tea is also maintained as a low bush in a continuous phase
of vegetative growth. Both these aspects call for manipulation
of plant parts for optimal productivity and growth.
|
|
|
|
Plucking
& Leaf Handling
: The plucking of the two leaves and a bud involves a number
of systems - Janam plucking, fish-leaf plucking , step-up
plucking etc.. Shear plucking is done when there is a scarcity
of pluckers during July to September. Pluckers' productivity
is found to be maximum in unpruned teas. The plucked leaves
are processed to produce the black tea.
|
 |
|
|
|
Withering
: 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 turgor, weight and volume.
Previously the flush used to be withered under the sun. Now
this process is generally achieved either by thinly spreading
the flush on mats, or in thick layers in troughs for 8-18
hours depending on the condition of the leaves.
|
|
|
|
Rolling
: The
object of rolling is to macerate the leaf so that the enzymes
and their substrates get intimately mixed up. This is achieved
mechanically either by the use of an orthodox roller, the
rotorvane, or by CTC (crushing,tearing and curling) machines.
Rolling ruptures the cell wall thereby enabling the production
of enzymes.
|
 |
|
|
|
Fermentation
: It
is the process of oxidation of leaves. The mechanical aspect
involves spreading out of the leaves macerated by rolling
a layer 5-8 cms thick, for 45 minutes to 3 hours, depending
on the quality of the leaves. Fermenting machines make the
process continuous, that is, every unit of macerated leaf
has to be spread out for individual treatment.
|
|
|
|
Drying
:
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 by blowing hot air through fermented leaves as they
are conveyed in chains. The drying process lasts for about
20 minutes.
|
 |
|
|
|
Sorting
: Sorting
may be defined as a procedure in which particles of bulk tea
are separated into grades of different sizes. This sizing
can be done either manually or by using different sizing equipments.
Sorting meshes of various sizes are used to grade the tea.
|
|
