Tea (Camellia sinensis) is an aromatic beverage commonly prepared by pouring hot or boiling water over cured leaves of the tea plant. After water, tea is the most widely consumed beverage in the world. It has a cooling, slightly bitter, and astringent flavor that many people enjoy. Tea have many of varieties. Such as White tea, Yellow tea, Green tea, Oolong tea, Black tea, Post- ferment tea.
In other hand tea is important to our health. Tea have many of health benefits. Tea may help reduce the risk of cardiovascular disease and some forms of cancer, promote oral health, reduce blood pressure, help with weight control, improve antibacterial and antiviruses activity, provide protection from solar ultraviolet light and increase bone mineral density. Green tea is also said to have “anti-fibrotic properties, and neuroprotective power.
Tea can grow in all elevation categories.
- Low country
- Mid country
- Up country
Normally the law of tea procession is similar, but slight of variations have between above three types. Tea is an green plant that grows mainly in tropical and subtropical climates Grow well within 18-250C. Optimum temperature is 22oC. Below 130C and above 30oC the growth may be reduced. Tea contains L-theanine, Caffeine, Gallic acid, Theaflavin, Thearubigin, Poly phenols and amino acid. whose consumption is mildly associated with a calm but alert and focused, relatively productive (alpha wave-dominant) mental state in humans. This mental state is also common to meditative practice.
Tea plants are propagated from seed and cutting; it takes about 4 to 12 years for a tea plant to bear seed and about three years before a new plant is ready for harvesting. In addition, tea plants require at least 127 cm (50 inches) of rainfall a year and prefer acidic soils. Many high-quality tea plants are cultivated at elevations of up to 1,500 m (4,900 ft) above sea level. While at these heights the plants grow more slowly, they acquire a better flavour. Under the tea plantation, we were studied about Low, mid and up country tea procession. We were visited to Pedro state in nuwaraeliya, tea state in Puswellawa, tea factory in Giragama to fulfill our purpose.
TEA MANUFACTURING PROCESS
Although each type of tea has different taste, smell, and visual appearance, processing steps of tea for all tea types consists of a very similar set of methods with only minor variations.
Tea leaves and flushes, which includes a terminal bud and two young leaves, are picked from tea bushes. Picking is done by hand when a higher quality tea is needed, or where labor costs are not prohibitive. The picker grasping the tea shoot using the thumb and forefinger, with the middle finger sometimes used in combination. Tea flushes and leaves can also be picked by machine, though there will be more broken leaves and partial flushes reducing the quality of the tea. However, it has also been shown that machine plucking in correctly timed harvesting periods can produce good leaves for the production of high quality teas.
- Withering/ Wilting: (16hr)
The tea leaves will begin to wilt soon after picking, with a gradual onset of enzymatic oxidation. 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. The leaves sometimes lose more than a quarter of their weight in water during withering. The process is also important in promoting the breakdown of leaf proteins into free amino acids and increases the availability of freed caffeine, both of which change the taste of the tea.
- Shaping: (30 mins)
The moist tea leaves are then rolled to be formed into wrinkled strips, 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. The strips of tea can then be formed into other shapes, such as being rolled into spirals, kneaded and rolled into pellets, or tied into balls, cones and other elaborate shapes. Within rolling, can be brake the leaves to start the reaction.
Polyphenol + PPoxidase Theaflavins + Thearubigins
- Roll breaking: (5mins)
Can be separate the different size particles using machines.
- Fermentation: (1 hr. 30 mins)
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. In this process the chlorophyll in the leaves is enzymatically broken down, and its tannins are released or transformed.
The tea producer may choose when the oxidation should be stopped, which depends on the desired qualities in the final tea as well as the weather conditions (heat and humidity) .For light oolong teas this may be anywhere from 5-40% oxidation, in darker oolong teas 60-70%, and in black teas 100% oxidation. Oxidation is highly important in the formation of many taste and aroma compounds, which give a tea its liquor colour,
strength. Depending on the type of tea desired, under or over-fermentation can result in grassy flavours, or overly thick winey flavours.
- Drying: (20 mins)
Drying is done to “finish” the tea for sale. This can be done in the ways including panning, sunning, air drying, or baking. Baking is usually the most common. Great care must be taken to not over-cook the leaves. The drying of the produced tea is responsible for many new flavor compounds particularly important in green teas.
- Sorting / Grading: (2hrs)
This is mainly based on the size of the tea leaves. Such as;
- Cloury BOPF
TYPES OF TEA
Tea is traditionally classified based on the degree or period of “fermentation” the leaves have undergone. These different grades of tea are determined generally by which part of the tea leaf or tip is used but the quality of the tea is also to do with where it is grown.
Young leaves or new growth buds that have undergone minimal oxidation through a slight amount of withering before halting the oxidative processes by being baked dry, with the optimal withering conditions at 30 degrees (65% relative humidity) for 26 hours. Withering of the leaves can last from around one to three days depending on the season and temperature of the processing environment. The buds may be shielded from sunlight to prevent the formation of chlorophyll. White tea is produced in lesser quantities than most other styles, and can be correspondingly more expensive than tea from the same plant processed by other methods.
This tea has undergone the least amount of oxidation. The oxidation process is halted by the quick application of heat after tea picking, either with steam, , or by dry cooking in hot pans. This process is time consuming and is typically done with pekoes of higher quality. The tea is processed within one to two days of harvesting, and if done correctly retains most of the chemical composition of the fresh leaves from which it was produced. Variation in steaming time for fixation or processing from additional stages of rolling and drying are sometimes used to improve or altering the flavor for types of green tea.
This tea is processed in a similar manner to green tea, but instead of immediate drying after fixation, it is stacked, covered, and gently heated in a humid environment. This
initiates oxidation in the chlorophyll of the leaves through non-enzymatic and non-microbial means, which results in a yellowish or greenish-yellow colour.
This tea’s oxidation is stopped somewhere between the standards for green tea and black tea. The processing typically takes two to three days from withering to drying with a relatively short oxidation period of several hours. The term “oolong” is used specifically as a name for certain semi-oxidized teas.
The tea leaves are allowed to completely oxidize. Black tea is first withered to induce protein breakdown and reduce water content (68-77% of original). The leaves then undergo a process known in the industry is “disruption” or “leaf maceration”, which through bruising or cutting disrupts leaf cell structures, releasing the leaf juices and enzymes that activate oxidation. The oxidation process takes between 45–90 minutes to 3 hours and is done at high humidity between 20-30 o C, transforming much of the catechins of the leaves into complex tannin. 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 rotovane consisted of an auger pushing withered tea leaves through a vane cylinder which crushes and evenly cuts the leaves.
It is done in the testing laboratory. Always follow the bellow steps.
- Weight 2.5 grams of tea leaves and put in to the pot.
- Add 200ml of boiling water to the pot and close the lid.
- Brew for exactly 5 minutes.
- Strain the water in to the cup.
- Place the tea leaves on the lid of the pot.
- Tea may be tested by sensory analysis.
DIFFERENCES AMONG THE UP, LOW AND MID COUNTRY TEA PROCESSES
There is White Tea which is extremely good for consumers and also the most expensive type of tea in the world, green tea and then grades of normal tea – OP (Orange Pekoe), BOP (Broken Orange Pekoe), FOP (Flowery Orange Pekoe) are processed into up country tea leaves. The warm humid climate together with a high rainfall is ideal for low-grown tea. 55% of the Sri Lanka ‘s black tea is produced in the Low Country.
Consider Low Country manufacture they make larger particles. They take out only the buds and smaller tips and manufacture the main bulk separately. Upcountry manufacture, they separate every different kind for different grades. They break up the smaller particles to produce FBOPF. Only the leaf will form Pekoe, only the stalk as OP,
the smaller BOP, etc. For Low Grown manufacture, fermentation period is much longer because all the juice is not extracted, as the leaf is fairly large, the cells are not 100% ruptured. So the enzymes are right inside. There is no way of sending oxygen in. The tea is left longer on the fermenting table in high grown areas than in low country, as oxygen availability in the atmosphere is more in Low country than in Upcountry. But the quality of the sun subjected on leaf is poor because they grow plenty of shade trees in low country. This prevents leaf from getting all the sunshine and in turn produces more chlorophyll. The more chlorophyll, after manufacture the tea will be blacker than leaf plucked from Nuwara Eliya area. That is why though NE tea has more flavor, the tea itself is brownish. People who love flavor tea do not bother about the appearance.
- Ganewatta, G. and Edwards, G. W. (2000) ‘The Sri Lanka Tea Industry : Economic Issues and Government Policies’, La Trobe University, (January 2000), pp. 23–25. Available at: https://ageconsearch.umn.edu/bitstream/123648/1/Ganewatta.pdf.
- Kottawa-Arachchi, J. D. et al. (2011) ‘Analysis of Selected Biochemical Constituents in Black Tea (Camellia sinensis) for Predicting the Quality of Tea Germplasm in Sri Lanka’, Tropical Agricultural Research, 23(1), pp. 30–41. doi: 10.4038/tar.v23i1.4629.
- Yashin, A. Y. et al. (2015) ‘Determination of the Chemical Composition of Tea by Chromatographic Methods: A Review’, Journal of Food Research, 4(3), p. 56. doi: 10.5539/jfr.v4n3p56.
- Industry capability report, 2014; Export development board