Tea processing transforms freshly plucked tea leaves into dried leaves for brewing tea. There are six main types of tea which are the result of differences in processing, not the plant itself. The basic steps are plucking leaves, withering to remove moisture, disruption to promote oxidation, oxidation to change color and flavor, fixing to stop oxidation, shaping, and drying. Oxidation levels determine the tea type from no oxidation in green tea to full oxidation in black tea. Fermentation through microbial activity is also important for puerh and black teas.

1. TEA PROCESSING
Presented by
Fatima Batool
Roll # 04

2. Tea processing -leaves from the tea plant
Camellia sinensis are transformed into
the dried leaves for brewing tea
starts with freshly-plucked leaf and ends
with ‘finished’, or ‘made’ tea.

3. There are six classes of tea (green, yellow,
white, oolong, black, and Puerh)
Come from same plant
The different types are the result of
differences in the tea manufacturing
process, and not due to different types of
tea plants.

4. Manufacturing procedure
 Although each type of tea has different
taste, smell, and visual appearance, tea
processing for all tea types consists of a
very similar set of methods with only
minor variations.

5. Plucking
Tea leaves and flushes, which includes a
terminal bud and two young leaves, are
picked from Camellia sinensis bushes
Collected twice a year during early spring
and early summer or late spring.

6. Picking is done by hand when a higher quality
tea is needed, or where labour costs are not
prohibitive

7. Withering/ Wilting
The tea leaves begin to wilt soon after
picking.
Withering is used to remove excess water
from the leaves and allows a very slight
amount of oxidation.
The leaves can be either put under the
sun or left in a cool breezy room to pull
moisture out from the leaves.

10. Cont…
 The process is also important in promoting the
breakdown of leaf proteins into free amino
acids
 increases the availability of freed caffeine, both
of which change the taste of the tea.

11. Disruption
 the tea leaves are bruised or torn in order to
promote and quicken oxidation.
 The leaves may be lightly bruised on their
edges by shaking and tossing in a bamboo
tray or tumbling in baskets
 More extensive leaf disruption can be done
by machinery.

13. Oxidation
 For teas that require oxidation, the leaves are
left on their own in a climate-controlled room
where they turn progressively darker.
 This is accompanied by agitation in some cases.
 oxidation occurs during the manufacture of
white, oolong, and black teas.
 Green and yellow teas are prevented from
oxidizing by steaming, drying and/or frying
techniques

14.  During the manufacture of tea, both
spontaneous and controlled oxidation occurs
 Oxidation in tea manufacture officially begins
during the withering stage as spontaneous
oxidation
 then accelerates gradually during the
subsequent steps necessary to transform fresh
leaf into finished black tea

15.  Oxidation process is often incorrectly
termed as “fermentation”
 In traditional oxidation, sieved leaf is
spread out in a thin layer (2-3 inches or 5-8
cm) on the floor of factory , on tables or
perforated trays

16.  Several chemical reactions occur
 Enzymes polyphenol oxidase and peroxidase
act on polyphenols to produce theaflavins.
 These red orange compounds react with more
polyphenols to produce thearubigins-
responsible for changing leaf’s color from
green to golden, coppery or chocolate brown

17.  Several flavor compounds produced by reaction with
sugars and amino acids
 Green Tea - no oxidation
 Yellow Tea -no oxidation
 White Tea slight, spontaneous oxidation occurs (8-15%)
 Oolong Tea- partial oxidation
 Black Tea fully oxidized
 Puerh always fermented, not always oxidized

18. Fermentation
 Fermentation is important in manufacture of Puerh
and Black tea
 Fermentation is microbial activity involving one or
more bacteria
 The leaves must be exposed to bacteria ( or have
bacteria present inherently) in order for fermentation
to occur
 exposure to oxygen during tea manufacture is often
reduced or eliminated after the withering stage for
fermentation

19.  bacteria required to both initiate and
maintain fermentation are potentially present
during several aspects of its production:
 1. On the surfaces of the leaf of the old-
growth plants themselves
 2. In the controlled environment of the tea
production rooms in which the ‘Raw’ is
temporarily stored

20.  the mounds of leaves that encourage the artificial
fermentation are stacked thickly, densely, and with
minimal surface area exposed.

21.  pile is stirred in frequently, allowed to rest
and generate the heat desired to encourage
the multiplication of microbes and the
paced decomposition of the leaf.
 Thermal blankets are often used to cover
the surface and further encourage the
process

22. Fixation / Kill-green
 is done to stop the tea leaf oxidation at a
desired level.
 This process is accomplished by moderately
heating tea leaves, thus deactivating their
oxidative enzyme

23. Rolling / Shaping
 The damp tea leaves are then rolled to be
formed into wrinkled strips, by hand
 or using a rolling machine which causes the tea
to wrap around itself.
 This rolling action also causes some of the sap,
essential oils, and juices inside the leaves to
ooze out, which further enhances the taste of
the tea

25. Drying
 Drying is done to "finish" the tea for sale. This can
be done by panning, sunning, air drying, or baking.
 The drying of the produced tea is responsible for
many new flavour compounds particularly
important in green teas

26. Aging / Curing
some teas required additional aging,
secondary fermentation, or baking to
reach their drinking potential