It includes various types of tea i.e White tea (Unfermented and Unoxidised) , Green Tea (Unfermented and Unoxidised) Oolang Tea (Semi-fermented) Black Tea (fully Fermented and Oxidised) It also includes all the steps involved in the processing of these teas.

1. Types Of Tea and Their Processing
Methods
By- Chinmaya Sahoo
(A-2017-01-031)
4th yr B Sc. Hons Agriculture

2.  Tea(Most widely drunk beverage after water)
 Scientific Name: Camellia spp. (2n=30)
 Family: Theaceae Or Cammeliaceae
 Origin : China in South-East Asia
 Morphologically ;
✓Tea is an evergreen shrub.
✓leaves are simple, alternate, serrate.
✓flower bisexual, with superior ovary.
✓ fruit is a capsule.

3.  C3 plant , Cross- pollinated crop and Polymorphic sp.
 Why ShouldWe DrinkTea?
 Protects Health ✓Tea is hydrating to the body
 Boosts Energy. ✓Tea helps fight free radicals
 Tea warms us up ✓Tea allows us to socialise
 Supports Mental Health. ✓Tea can help us reduce stress
 Regulate Blood Sugar. ✓Tea can help you cut down on calories
 Aids Digestion. ✓Strengthened Immune System

4.  Typesof tea
 There are various types of tea, all produced from the same plant Camellia sinensis.
 Tea are mainly classified according to method of processing.
 The conventional teas include: totally fermented black tea, raw or unfermented green
tea and white tea and partially fermented Oolong tea.
 The non-conventional tea products are instant tea (cold- and hot-soluble), flavored tea,
and decaffeinated tea.

5.  Beside these all recently new trend came in the tea market with the numerous
products such as canned or bottled teas, soluble tea mixes, tea beverages,
frozen tea liquid, and tea tablets are convenience products.
1. White Tea – Unfermented
2. Green Tea –Unfermented
3. Oolong Tea - Semi-fermented
4. Black Tea - Fermented

6.  White Tea
 White tea is made from top buds and young leaves (not fully opened) that
have been steamed to inactivate polyphenol oxidation and then, dried.
 Since white tea made from unfolded tea buds having pubescence which give
silvery appearance to final product hence called as 'White Tea’.

7.  Polyphenols percentage is highest in the bud and gradually decline with age of leaves so
due to highest percentage of polyphenols in bud, White tea is considered to have high
therapeutic value.
 White tea is considered as one of the most expensive tea for consumer and more
remunerative to producer.

9.  GreenTea
 Green tea leaves are not oxidized and are unfermented.
 Manufactured in such a manner that the oxidation of green leaf polyphenols is prevented.
 If the shoots are left as such then the polyphenols are acted upon by the enzyme
polyphenol oxidase and are oxidised to quinines.
 To prevent this oxidation of polyphenols, it is essential to fix or inactivate the enzyme
polyphenol oxidase.
 It has the largest number of varieties, each with its own unique flavour and aroma.

11.  Oolong Tea
 Oolong, is a traditional Chinese tea produced through a unique process including
withering the plant under strong sun and oxidation before curling and twisting.
 It combines green tea’s finishing techniques and black tea’s oxidation
 Oolong tea is 'semi-fermented' and also known as hybrid of black and green tea.
 Oolong tea possesses characteristic of both black and green tea.

13.  BlackTea
 Black tea is a fully oxidized tea.
 Black tea manufacture involves crushing the tea leaves to promote enzymatic oxidation
and subsequent condensation of tea polyphenols in a process known as fermentation,
which leads to the formation of theaflavins and thearubigins.
 The catechins and theaflavins (in black tea) are the microbiologically active molecules
 It is generally Stronger in flavour than the unoxidised one.
 Black tea retain its flavour for several years and most
widely produced and drunk tea in the world 🌍.

15. Green tea Black Tea
Process Short, no fermentation Longer Fermentation
Colour Green or yellow Red or black
Taste Sweet after bitter Distinct flavour, added in sugar and/ or milk
Antioxidant In general, more Polyphenols More Flavonoids
Caffeine Less More
Quality Better in fresh Depend on produced location
Health benifits More in general:
may irritate to empty stomach
Cardiovascular system

17.  Instant tea
 Instant tea is a powder in which water is added, in order to reconstitute it into a cup of
tea.
 Instant tea granules are made by using low pressure to extract liquid from fresh tea leaves.
 The liquid is then freeze dried to form a powder.
 Unfortunately, this type of processing destroys most of the antioxidants that make tea
such a healthy drink.

18.  In fact, according to USDA report powdered iced tea loses more than ninety percent of
its antioxidants when it’s processed – and some instant teas have almost no antioxidant
catechins, once it’s reduced to a powder.
 If you’re drinking tea for its health benefits, you’re cheating yourself when you use
instant tea granules.

19.  FLAVOREDTEA
 Tea is referred to as ‘flavored’ if it has supplementary taste and/or aromas added to it.
 Flavoring is done to satisfy diverse tastes and provide enticing aromas.
 These added flavorings may be from natural plants, other substances (such as oils), or
synthetic sources.
 Flavored teas are further divided into 3 categories i.e. naturally flavored, artificially
flavored and herbal flavored.

20.  NaturallyFlavored Tea
 This is tea whose aroma and tastes has been enhanced using naturally-occurring or
plant substances without any artificial additives.
 Examples are essential oils, aromatic substances and more. Such a tea would be Jasmine
Green (when its naturally flavored using the jasmine flower).

21.  ArtificiallyFlavoredTea
 This is tea that uses flavors that have been synthetically manufactured from chemicals,
to end up producing some popular tastes and aroma.
 The flavors are then applied on the tea for consumption adding an aromatic or complex
flavor experience.

22.  HerbalFlavoredTea
 The flavors are derived from natural plants like roots, flowers, fruits, or plant barks
that have pleasant aromas and flavors.
 These are then added to tea leaves to produce the resulting herbal flavored tea, sometimes
referred to as herbal tea.
 While the primary purpose is usually to add a sweeter or more complex flavor and aroma
to the tea, oftentimes the herbs are used to add medicinal value to the tea. An example
would be Belight Tea.

23.  DecaffeinatedTea
 Decaffeinated tea is tea leaves that have undergone a process that removes most of the
caffeine.
 By law, tea labelled “decaffeinated” must contain less than 2.5% of its original caffeine.
 Because of this law and limitations in the process, no decaf tea is actually caffeine free.
 Any type of tea can be decaffeinated, although black and green teas are popular.
 If you are one to lose deep sleep because of too much caffeine, decaffeinated
tea is something worth looking into.

26. ~Processing of Black Tea~
 Today, the majority of tea harvesting (plucking) is still done by hand.
 The uppermost section of the shoots of the tea plant, where the young, tender new leaves
and buds are found, are plucked for making tea.
 The development of the new buds and leaves is called the flush. Thus the term first flush
refers to the first development of buds and leaves, generally occurring in the Spring.
 The grade of tea depends on the time of harvest (Spring time first flush generally being
the best) , what part of the tea plant is plucked, and the quality of the plucked leaves.

27.  For superior teas, the bud or the bud plus youngest leaf is plucked.
 For most good to average teas, the bud and top two leaves are gathered and for average to
below average grade teas, plucking may consist of the bud, top two leaves, and the older
leaf below them. Plus some of the twig.
 Harvested fresh leaves are sent to the factories where they undergomechanical process
associated with the manufacture of the finished product.
 The process involved in the manufacture of black tea are :
1.Withering 2.Rolling 3.Fermentation 4.Drying/Firing 5. Cleaning and Sorting
6.Grading. 7.Packaging

28. 1. Withering
 This step is performed in order to remove moisture from the freshly plucked tea leaves. During
withering it is necessary that air should circulate as freely as possible around the leaf.
 This is usually achieved by use of a withering trough consist of a long, narrow, rectangular box fitted
with a perforated floor through which a fan blows air upward through a shallow bed of leaves.
 An air heater may be fitted but it is important to avoid over heating of leaf and the leaf temperature is
usually maintained close to ambient.

29.  Withering times of 12-16h are most common. The moisture content of leaves during
withering is decreases from 78% to about 68-55%.
 Withering is a conditioning step of the leaf to prepare it for the next step of rolling.
 The know biochemical transformation during weathering are liberation of amino acids.
 Changes in organic acids and increase in caffeine content, sugars, polyphenol oxidase
activity, formation of volatile components and increase in cell membrane permeability
and leaf during withering absorbs more oxygen to enhance oxidative reaction.

30.  As a result of physico-chemical changes occurring during withering, overall concentration of the cell sap
increased. So leaves are conditioned for good fermentation, which in turn is directly responsible for the desired
quality of finished black tea.
 The following tests should be done to judge whether good withering of tea is obtained.
1.Well withered leaves should not produce cracking sound when squeezed.
2.Withered leaves when pressed with the hand should form a compactball.
3.The stalk of the withered leaf should not be brittle.(Green tea does not go through this process)

32. 2.Rolling
 Rolling is carried on by machines. The purpose of this step is to break apart and expose
the oils in the tea leaf to release the enzymes that will interact with air and promote
oxidation of the leaf.
 As different machines operate most effectively at different moisture contents, and thus the
choice of method of leaf disruption affects the requirements for both withering and drying.
 Leaf disruption is carried out by: -
(a) Orthodox Roller (b ) Crush, tear and curl (CTC) machine

33.  (a) Orthodox Roller:-
 It is a batch machine. Here a batch of leaf is loaded into a cylindrical hopper positioned
above a circular table bearing a series of ridges on its upper surface.
 Downward pressure is placed on the cylinder of leaf in the hopper, forcing the leaf at the
lower end into contact with the table.
 The table and hopper move eccentrically to each other, bruising, rolling and disrupting the
leaves. Varying the downward pressure on the cylinder can vary the degree of disruption.
 The orthodox roller requires a fairly dry leaf with moisture content of about 60% und
output contains a relatively high proportion of large particles.

34. FOR 3.5 Quintal of leaves FOR 1.5 Quintal of leaves

35. (b) The CTC Machine
 Machine is very widely used and produces small particles, popular for use in tea bags.
 The machine basically consist of one or more pairs of contra rotating rollers. The surfaces
of the roller are machined in a patter designed to give a tearing and cutting action and this
is aided by a speed differential, usually. 10:1 between the rollers.
 A CTC machinë produces a high value product and handle leaves with relatively wide
range of moisture contents, but operates most effectively at 68-70%.
 Cooling air is supplied to prevent over heating of the leaves

37. Advantage of CTC over Orthodox process
� Leaf distortion is much greater
� Fermentation is faster
� Liquoring properties are improved
� CTC and Lawrie Tea Processor (LTP ) {a modern CTC machine} teas have higher
levels of theaflavins and thearubigins and therefore have more colour and are brighter and
brisker than orthodox teas.

38. 3.Fermentation
 Fermentation is the process during which the polyphenols in the tea leaf are oxidized in
presence of the enzymes (polyphenole oxidase) and subsequently condensed to form
colored compounds like Theaflavin and Thearubigin that imparts tea character to the
black tea.
 In this process rolled leaf is put fermentation finks specially made of tiles, cement or
aluminum. Amount of O, supply, temperature and fermentation period are three main
parameters that determine the quality of tea during this process.
 An adequate supply of air to each tea particle is necessary as all the chemical and
biochemical reactions that occur during this period are oxygen dependent

39.  The optimum temperature for fermentation process is in between 24°C-29°C.
 Fermentation period varies from 2 to 3 hrs depending on the type of leaf, degree of
wither, temperature, availability of oxygen and fermenting ability of the tea flush.
 Fermentation is a very sensitive process. Even 5 minutes time delay in adjusting the
correct fermentation period is likely to deteriorate flavour appreciably.
 During fermentation the leaf changes colour and become dark coppery. A typical aroma
develops at this stage.

41. 4.Drying (firing)
 Drying of tea invariably involves the use of hot air. In the early stages of drying,
enzymatic reactions continue and some of the end products are of importance in
determining the character of the made tea.
 Ultimately, however, enzymes are inactivated or destroyed by heat and the reduction in
water activity level
 The water content of tea at the end of fermentation is about 60-72%, which is reduced to
about 2.5 to 3.5%.
 Firing is done at temperature 85-90°C For better keeping quality and flavour.
 The drying is carried out by belt dryers or fluidized bed dryers.

42.  Belt dryers are of the multi-pass type, in which tea travels along a series of perforated
belts mounted in a hot air chamber.
 The most common configuration is four to eight belts stacked vertically.
 Tea enters at top of the dryer and air at the base (counter current).
 As each pass is completed the tea falls onto a lower belt, finally leaving the dryer through
a discharge value.

44.  In fluidized bed dryers the product is deposited on the perforated floor and hot air is
blown upwards through the floor at a velocity controlled between that needed to expand
the product bed and that at which individual particles float.
 The bed may either be stationary or vibratory and mechanical sweeps are often fitted to
assist product movement through the dryer.

46. 5.Cleaning andSorting
 Tea leaving the dryer is in a relatively crude state and consists of a mixture of different
sized leaf particles together with a quantity of stalk and fibre.
 The tea is sorted into portions by size, during passage through a vertical stack of
vibrating mesh screens.
 Stalk and fibre is removed by electrostatic attraction during passage close to electrically
charged rollers.

47.  The particle size in each portion, the grade, is determined by the size of the mesh.
 The humidity in the cleaning and sorting room should be as low as possible both to
minimize moisture pick up by the tea and to ensure effective operation of the electrostatic
cleaning equipment.
 In areas of high humidity, localized heating in the vicinity of the electrically charged
rollers is required.

48. 5.Grading of tea
 Tea grading has not been standardized between major growing countries.
 The leaf grades result exclusively from the last stage of production, the sorting stage.
 There are 4 basic groups in orthodox production: Leaf, Broken, Fannings and Dust.
 Tea grades commonly refer to leaf size and location on the tea bush.

51. 7.Packaging
 At the point of production vacuum packing of tea is carried out in aluminum foil-
polyester-polyethylene laminates, which are of extremely low oxygen and
moisture permeability.
 Although the traditional wooden tea chest has remained in use, Multiwall Kraft
paper sacks have been developed for tea.
 Leaf tea is retained in two basic forms, loose in paper containers within a
cardboard outer or in tea bags.

53. ~processing of Green Tea~
 Green tea differs technologically and chemically from black tea.
 The fermentation stage is completely omitted from processing and enzymic activity in
the leaves is inhibited by heating (steaming or pin-firing) as soon as possible after
plucking.
 The character of green tea is thus largely determined by the endogenous components of
the leaves at the time of plucking, rather than by compounds formed in post harvest
reactions.

54. Steaming
 The “Steamer” is an additional equipment needed for the manufacture of green tea.
 The fresh leaf is placed into a hexagonal wooden drum which can be revolved on trounions and through which
a perforated steam pipe in carried.
 The steam from the pipe impinges on the leaf as the drum revolves and with steam at a pressure of 30 to 40
pounds per square inch.
 Sterilization of the leaf should be complete in about two minutes. If the leaf is well steamed, it will be firm but
pliable, if over steamed it will be squashy looking very important to cool the leaf immediately after steaming to
avoid over steaming

56. Rolling anddrying
 As soon the leaf has cooled down sufficiently and adequate quantity has accumulated for a roll, it should be placed
in the roller the pressure cup should be lowered on the leaf and sufficient pressure exerted for two minutes to drain
off all water in the leaf.
 The water so expressed should be collected and thrown away and the roller set in motion.
 Rolling should be carried out for 10 minutes with slight pressure and again for 5 minutes without pressure.
 The leaf after rolling should be passed rapidly in and out of a firing machine at a temperature of 94 – 96°C and
any lumps broken up by hand, but this should not be done until the leaf has become pliable as too much dust will
result.

57.  The firing should be continued until the leaf has acquired a slight gummy feel and an olive green appearance.
 It should again be laid out to cool when any crispness caused by firing will soon disappear.
 When cool, the leaf will be ready for rolling again which usually requires from 20 minutes to half an hour.
 The final rolling is merely to give the requisite twist and appearance to the leaf, and only sufficient pressure should
be applied to produce these results. The final firing should be done at a temperature between 94°C to 96°C.

59. ~Processing of Oolong tea~
 The first stage involves outdoor withering in the sunlight. Sunlight is important in
initiating biochemical reactions involved in producing the character of semi-fermented
teas.
 Outdoor withering is a simple process in which fresh shoots are spread onto shallow
bamboo baskets.
 During outdoor withering the temperature increases to 35-40°C, the length of the wither
ranging from 30 to 60 min, depending on the ambient temperature.

60.  After the outdoor wither, the tea is transferred to the floor of a withering room for the
indoor wither at room temperature.
 This lasts 6-8h in the case of oolong tea. During the indoor wither the leaf layer is
manually agitated every hour.
 The withered leaves are then pan-fired at 250-300’C for 15 min.
 Pan firing inactivates enzymes and terminates biochemical changes,
 The remainder of the processing is the same as that applied during the production of pan
fired green tea.

62. References
 Foods – facts and principles by N.Shankuntala Manay and N.Shadaksharasway .
Published by- New age international (P) Ltd. New Delhi.
 Tea cultivation in Himachal Pradesh, (D. K. Sharma and Parmod Verma)
 Cultivation and manufacture of Tea ( Dr. Himadri Panda)
 Tea cultivation to consumption (K.C Willson and M.N Clifford)
 The cultivation and manufacture of Tea (Lt.Conl Edward Money)
 Organic tea – cultivation and marketing by N.Ghosh Hazra. Published by –
International book distributing co. Lucknow.