The procudtion of green tea
The best green teas are plucked and hand-processed in the spring months of March and April (First Flush).
In this period, first and foremost the youngest white buds, one leaf and a bud or two leaves and a bud are collected.
For less expensive green teas, which are plucked by hand later and processed mechanically, the bud with up to four leaves is plucked. Very cheap teas are harvested with machines.
Famous types like e.g. Cui Min, Longjing, Pi Lo Chun, Mao Feng, Mao Jian etc. are not only harvested in spring. Moreover, they can be processed by hand as well as mechanically. Thus, each type of tea is offered in very different qualities at very different prices. For example, a Mao Feng is not automatically a good tea just because it carries this name. It much more depends on the harvest time, the plucking method, the leaf material and the accurate and careful processing. Only with the optimisation of these procedures, a Mao Feng will become a good Mao Feng.
The best qualities produced by hand in spring accumulate only to small quantities. They are very expensive and rarely exported to Europe. For these rare qualities the tea farms can gain 500 Euro per kilogram and more in China, Japan and other Asian countries.
The traditional hand processing
After the tea leaves are being subjected to a short drying process at room temperature, the actual manufacturing process takes place. The tea leaves are shortly heated at a high temperature, this way deactivating the enzymes and stopping the oxidation of the tea. In the traditional hand processing, the heated tea leaves are moved and lightly roasted in a pan until they are soft enough not to break in the following rolling process.
During this process the tea leaves are formed into ca. 10 centimetres large balls, which will be again and again dissolved and formed with special hand movements which depend on the type of tea to be produced. This is done until the tea leaves have a certain shape and colour. In doing so, the single tea leaf acquires its peculiar contorted shape.
Afterwards, the tea leaves are once again moved by hand in pans and thus dried externally. After cooling down they are rolled again and so forth. With this careful technique, the moisture is taken out of the tea.
When this process is completed, a charcoal fire is lighted up and a raffia basket without bottom is put on top of it. For the final drying the tea leaves are put on a cloth which is laid over this basket. In modern tea factories, this fire is replaced by a trough, in which hot air is blown. At last the tea leaves are hand-picked, classified and packed in sacks or cartons. For these hand processed teas, the daily production of 12 workers is generally around ten kilograms. Since this process is very costly, companies use more and more machines for the processing of the tea. This decreases not only the production costs, but also the quality of the tea.
Longjing tea is processed in a very similar way. The only difference is that in this case, the fresh tea leaves are not formed into balls, but they are rather pressed flat with hands. Like this, Longjing tea gets its typical flat shape.
One person by hand can process only one kilogram of Longjing tea in eight hours. The heating, moving, pressing and cooling of the tea leaves is repeated until only ca. four percent of moisture remains. The best Longjing teas, which are harvested at the first plucking at the beginning of the year, can reach prices of up to 500 euro per kilogram in the Chinese market. In some cases it can be sold for more than 1000 euro.
The above-mentioned hand processing is today only practiced in China.
The low-cost green teas, which are predominantly consumed in western countries, are processed mechanically. After the withering of the tea, which mostly has been harvested mechanically too, the deactivation of the enzymes takes place through the heating of the tea leaves at high temperatures. Afterwards, the tea is rolled in machines between rotating metal disks and then roasted and dried in heated metal drums. With this method for example Chun Mee green tea is produced. Gunpowder, a tea of round shape, is won by sifting it out of the Chun Mee production as well as by the rolling in heated wok-like pans, in which a kind of stirrer rolls the tea leaves into small balls.
At last, the teas are sorted by the size of the leaves, this way also automatically separating the unwanted ribs. Together with the processing, the size and the texture of the dried tea leaves determine the quality and the price of the tea.
The cheapest green tea varieties are harvested in summer and autumn and are mechanically processed. Very good quality tea cannot be processed in these periods, because of the strong sun radiation, the heat and aridity. At this time, teas are harvested and processed only when there are orders from abroad and cheap quality teas are requested. In many places, the production rests during this period.
The Japanese method
This indicates a method in which the mechanically plucked, fresh tea is fully-automatically passed through a production line. At the beginning of the processing, the tea leaves are steamed with 110 degrees Celsius water steam. With this step, the enzymes are deactivated and the oxidation of the tea leaves inhibited. Instead of the rolling process, the tea leaves are automatically pressed flat with a sort of metal flail. This way the tea assumes its flat shape, similar to Longjing tea.
This steamed tea is known as Sencha. After repeated cooling, flattening and drying, at the end of the process the tea has a residual moisture content of four percent. At this point, the tea is cleaned and sorted according to the leaves’ size. In the last step, the tea is put in a vacuum pack, which lastingly protects it from subsequent oxidation. In Japan, the hermetic storage in cold storerooms is standard. This preserves the aroma of the tea for a long period of time.
Japan, with its enormous tea consume, established this method as a tea import country in almost all the production areas of the world.
The production of yellow tea
Regarding the question “What actually is yellow tea?” the opinions of the experts diverge. From what we know we still can roughly picture the characteristics of the production process of yellow tea.
It is certain that for the production of yellow tea mainly the same processes are done like for green tea. Through an additional processing step the tea is “yellowed”, in Chinese Men Dui Wo Huang, which translates roughly to “tightly sealed moist yellowing”. For this the tea is wrapped in portions and “yellowed” for one to several days in a warm room. During this period the tea leaves are unpacked and re-wrapped. Depending on the type of tea the “yellowing” can be done before the rolling, after the rolling or even after the first drying. During this production step a very light fermentation happens intentionally. The colour of the leaves and the colour of the infusion change into yellowish.
There can be a further step, in which the tea leaves are spread out on large bamboo trays, similar to the production of white tea, and exposed to fresh air. During this process the leaves react with the oxygen in the air and a natural oxidation process starts. Experts determine when to stop this process. If ready produced green tea smells or tastes too “grassy”, this aroma can be eliminated by this last step. Teas undergoing this treatment are sometimes also called yellow tea in China.
Probably only Chinese tea experts are really able to sensorially distinguish yellow tea from green tea.
The most known types of yellow tea produced according to these methods are:
- Jun Shan Yin Zhen – from Hunan province
- Wen Zhou Huang Tang (“yellow soup”) – from Zhejiang province
- Huo Shan Huang Ya (“yellow bud”) – from Anhui province
Whatever the scientific status on positive health effects, the Chinese population has allegedly used yellow tea intuitively since centuries as medicine to purify kidneys, liver and spleen and as a help for stomach problems.
We are not aware of reliable scientific researches that examine yellow tea separate from green tea and which would verify these properties of yellow tea. However, there are studies on green tea in which also yellow teas were examined, which confirm their positive effects on health.
The production of jasmine tea
Jasmine tea is a classic Chinese product, which is rarely manufactured in other countries. For the production of jasmine tea, many different qualities of green tea are used as bases (rarely also excellent white teas). For the traditional scenting of this tea, only fresh jasmine flowers can be used. For low-cost jasmine teas, also magnolia flowers are used. The usage of flavouring substances is not known in China so far.
The traditional production process starts already in the night of the harvest of the jasmine flowers, as during the night the intensity of the essential oils is at its strongest. Jasmine flowers that have been subjected to a long transportation cannot be used for the production of jasmine tea anymore. Therefore, it is necessary that the processing factory is situated directly in the proximity of the growing area of the jasmine.
The tea is brought to the flowers for processing and not vice versa. For the scenting of organic green tea, the jasmine flowers are placed between layers of gauze, which avoid the jasmine flowers getting in direct contact with the tea (protection from contamination): a layer of gauze-packed jasmine flowers is spread out, then a thin layer of tea leaves is put on top of it, another layer of gauze-packed flowers is laid over the tea leaves and so on. From Midnight to the following noon, the essential oils of the jasmine flowers are released and give flavour to the green tea leaves.
After this first aromatisation process, again around midnight the now-dry jasmine flowers are replaced by fresh flowers and the process of scenting starts once again.
For simple jasmine teas, the described scenting process is carried our three times. After three days (72 hours) they are ready for consumption. The dry jasmine flowers are removed, the tea is sorted into different leaf sizes and packed for shipment. For a three-times scenting of 100 kilograms of jasmine tea, the essential oils of ca. 100 kilograms of jasmine flowers are required.
For better jasmine teas, the process is repeated up to ten times. But of course not only the number of aromatisations is decisive for the quality and the price of a jasmine tea, but also the quality of the green tea.
Normally light, aromatical kinds of tea are used to produce jasmine tea, because they accentuate the taste of the jasmine the best. The taste of fresh jasmine flowers merges at best with the most exquisite white and green teas. Examples for this are: Jasmine Chun Hao, Jasmine Dragon Phoenix Pearls, Jasmine White Silver Needle.
The production of black tea and the semi-fermented Oolong tea
Worldwide, black tea is predominantly hand-picked. In China, the harvest is normally conducted with a kind of motored hedge trimmer with a big trap bag. Because the consume of black tea is very limited in China, therefore they produce black tea explicitly for export, predominantly a cheap type.
For the harvest of black tea in China, the form of the tea bushes is adjusted to the form of the cutting device of the machine, so that an even harvest of the young sprouts is possible.
Actually, only two leaves and a bud should be plucked for a good quality black tea. Today, this method is practiced more and more seldom for budget reasons.
The machine cuts ca. five leaves, because the market outside China rather demands low cost tea instead of high-quality ones.
The freshly harvested tea leaves are put in layers on big sieves. Some ventilators aerate these sieves and wither the tea leaves until they are soft and elastic.
The withered leaves are rolled in special machines between rotating metal disks to break up the cell nuclei.
After breaking up the cell nuclei, the tea is spread out once again in layers on fermentation tables to aerate. The oxygen causes the leaves, which are still moist, to oxidise. In this way the tea acquires a dark, red-brown infusion colour.
The tea expert determines the level of fermentation. If a very strong tea with a dark colour is required, then the tea leaves have to stay longer in the oxidation process. If a lighter infusion colour is desired, like the one of Darjeeling First Flush or of the semi-fermented Oolong tea for example, the oxidation process is interrupted earlier.
The combination between the quality of the harvested tea leaves, the climate and the professional processing of the fresh-plucked leaves in the tea factory determines the colour and the taste.
The so-called semi-fermented Oolong teas can have, depending on the duration of the fermentation, a greenish, light yellow colour to a red-brownish one and can thus be close in taste either to green tea or to black tea. In general, Oolong teas taste rather mellow and flowery.
The fermentation process is stopped by passing the tea leaves through a dryer at a temperature of 90 degrees Celsius.
The sifting and grading
After the dried tea leaves are mechanically cleaned from stems and ribs, they are sorted by screening.
These screenings are named differently around the world:
The first screening, the biggest, is normally referred to as leaf tea, in China with names and numbers, in India with grades like OP, FOP, GFOP, TGFOP, FTGFOP – just to name the most important.
The second screening is called e.g. Pekoe, FBOP, Black Qucha, Black Gunpowder etc.
The third screening is called Broken, respectively GFBOP, GBOP, BOP etc.
The fourth screening, named Fannings, BOPF or OF etc., is used mainly for infusion bags.
The fifth screening is called Dust or BOPD, PD etc.
The production costs for all the five screenings (five grades) are the same. The first screening realises of course the highest price, while the fifth has the lowest.
The smaller the sifted leaf size, the more modest is the price and the stronger is the taste.
The production of white tea
Real white tea is a typical Chinese product (traditionally coming from the province of Fujian), for which only very special tea leaves from particular tea bushes (cultivars) are used. These tea leaves respectively the buds are characterised by their white hair coat.
For the production of white tea mainly the following four tea bush cultivars are used:
- Fuding Da Bai Cha
- Fuding Da Hao Cha
- Zhenghe Da Bai Cha
- Minbei Shuixian
Da Bai means “big [buds], white [hairs]”, Da Hao “big [buds], [many] hairs” and Shuixian means “daffodil”. Cha is the Chinese word for tea.
The names Fuding, Zhenghe and Minbei indicate different regions in Fujian province respectively the tea plants that are indigenous there and which provide the best raw material for white tea.
Decisive for the quality of the white tea is not only the tea plant, but also the moment of plucking, e.g. in spring or autumn, when the climate is right for the fresh buds of the Da Bai bushes to show their nicest white hair coat.
If only the buds of the Da Bai or the Shuixian bush are picked by hand, then they make the best, most expensive raw material for the production of white tea. It is called Da Bai or Shuixian Bai (white Shuixian). If two leaves and a bud are plucked from the Da Bai or the Shuixian bush, then these fresh leaves are called Bai Mu Dan (white peony). In Europe, this tea is also called Pai Mu Tan.
Traditionally and predominantly in the provinces of Fujian, Zhejiang and on Taiwan, in spring Shuixian Bai is plucked first, then Da Bai and finally Bai Mu Dan. There can be three harvests per year.
White tea is offered in five product groups:
- Bai Hao Yin Zhen (Silver Needle)
- Bai Mu Dan
- Shou Mee
- Gong Mee and
- new white tea (modernised production method, possibly bad leaf material)
All these products are available in different grades and qualities.
Nowadays, white tea is also produced in other Chinese provinces, but not always is there big attention to the right raw material, or the suitable tea bush cultivars are not available to produce high quality white tea.
The teas then show little or no white tips and the tea leaves have a relatively dark, brownish colour. These “white teas” are cut for infusion bags also.
The traditional production process
For the traditional production of the finest white tea, still today only the young, white-haired buds are hand-plucked directly after the first shoot in spring. The fresh buds are laid out on big bamboo trays. The tea leaves wither at air temperatures between 18° and 25°C and ca. 70 percent humidity. During the 48 to 72 hours of drying, the tea leaves are again and again ventilated by hand. In case of bad conditions outside, this process takes place in rooms.
The tea leaves lose ca. 85 to 90 percent of their moisture content during this drying and a light oxidation (fermentation) occurs. A strong fermentation is inhibited by not rolling and thus breaking the leaves, hence no cell fluid can oxidise in the air. In the past the final drying was done by hand in wok-like pans heated with charcoal, later with electric heating. Nowadays the final drying is predominantly carried out by modern machines. The most expensive white tea varieties, for which only the white buds or two leaves and a bud of the traditional cultivars are used, can today also be found in European retails for an appropriate price.
In the 70's, the production of white tea has been modernised and engineered.
In present time, cost savings are often put first at the expense of the costly processing of high quality products. Therefore, traditional harvesting and production methods are more and more replaced by cheaper methods. Cheap products more easily find buyers because of their low prices. For the processing with modern methods for export today, at best the white bud with the two youngest leaves of a traditional cultivar is picked.
To some extent, however, bad leaf material and leaves from inappropriate tea cultivars are used. It is also not seldom that the material is harvested by machine. By doing so, the quality decreases enormously. The qualities of Bai Mu Dan vary accordingly. While in the past the right plucking material was of great importance for the production of white tea, today the processing has come to the fore. Hence, white tea is nowadays often defined only by the processing method.
In the modern production process, the freshly harvested tea leaves wither in the sun (in case of bad weather in rooms) at normal temperatures. This process lasts approximately 24 to 28 hours, during which the leaves lose 26 to 28 percent of their moisture content.
The tea leaves are then put in layers of about 20 to 30 centimetres height in order to slightly ferment (oxidise). For good plucking material the colour of the buds then changes from fresh grey-green to white. For the final drying, the tea leaves are moved in a heated drum. Through this procedure the activity of the enzymes is blocked, further oxidation prevented, the preliminary drying process shortened and the production time cut in half.
Taste and health
The quantity of white-haired leaf buds determines the quality of the white tea. When infused, these teas show a clear, light, almost white colour with a fresh, aromatical, flowery and gentle taste. A good Bai Mu Dan has a light yellowish infusion colour, with an earthy, aromatical and fine taste. A bad Bai Mu Dan displays a reddish-brown colour in the cup and a bland, earthy taste.
The very expensive white teas, for which only white haired buds are used, are said to be especially recommendable for good health because of their components.
Research findings show that by drinking white tea blood pressure, blood fats and blood sugar decrease, free radicals are reduced and the immune system is strengthened.
The production of Pu Erh tea
The three harvesting periods of the year take place in spring, summer and autumn. With the first flush harvest from March to May, ca. 20 percent of the total yield quantity is produced, 50 percent with the second flush harvest from June to August and 30 percent with the third, final flush harvest from September to November. The best quality is usually plucked at the beginning of spring. Since the yield is still low at that time, the plucking of a certain quantity of tea lasts longer than in summer or autumn. Therefore, in spring the costs for the same quantity of plucked leaves are higher. It can be plucked by hand according to the requirements, first grade material (one bud and one leaf), second grade (one bud and two leaves) as well as third grade material (one bud and three leaves). For cheaper Pu Erh, the tea is harvested by machine as well. With this method, often more than just the three youngest leaves will be cut. Machine harvesting only takes place in summer and autumn.
Whether the plucked tea leaves are processed into green tea, white tea, yellow tea, black tea or Pu Erh tea and how the leaves are going to be shaped, will be decided according to the order situation.
The quality of a Pu Erh tea depends on the quality of the collected leaf material and on the harvest time. First grade Pu Erh is therefore the best quality and realises very high prices in China. Pu Erh teas which were produced from machine plucked material are solely exported, have a lower quality and cost just a fraction of the high quality Pu Erh.
The production of green and black Pu Erh tea in the tea factory
The first three steps in the production of the Pu Erh tea are the same as for green tea.
Green Pu Erh tea
- The fresh leaves are withered (externally dried) for three hours in the shade;
- The withered tea leaves, as for green tea, are heated in a mixing drum at 260 to 280 degrees Celsius. Given that ca. 20 percent more tea leaves are moved in the mixing drum compared to the production of green tea, the enzymes are not as strongly reduced as for green tea. Through this process, a too quick fermentation (oxidation) is inhibited.
- The heated leaves are shortly cooled and then rolled in the rolling machine under light pressure for ca. 7 to 8 minutes.
- The tea is then laid on bamboo filters and dried in the sun for 6 to 8 hours.
Black Pu Erh tea
- The dried green Pu Erh tea is moistened with pure, natural spring water until the tea leaves reach the right dampness;
- The damp leaves are piled up into a 1,20 meter high pyramidal mound, like for composting, and covered with cotton cloths;
- As for compost, inside the pyramid a temperature of ca. 50-60 degrees is reached and the tea ferments (oxidises) intensively;
- Every 5-7 days the pile is turned to allow a uniform fermentation. Altogether the tea is turned and piled up again for 4 to 5 times.
- Subsequently the tea dries and ferments for ca. 30-40 days at normal temperature. For this the tea is laid out 40 centimetres high.
- After this the tea leaves are screened in different sizes, sorted, if necessary pressed, stamped and packed.
- Pu Erh tea further oxidises and becomes darker with the time and stronger in taste. Old Pu Erh tea is therefore considered very valuable in China. The older the tea, the more expensive it is.
Pressed Pu Erh tea
Pu Erh tea is also known as dark tea in China, which is sold in pressed form on the Chinese market. These teas are partly decorated with motifs and pressed in different shapes, for example in tea cakes, tea bricks, Tuo Cha or Mini Tuo Cha. The forms and motifs are manifold. The tradition of pressed tea can be traced back to when caravans transported tea along the Silk Road.
Horses and camels could thus be loaded with higher quantities of tea. The tea is pressed with hydraulic presses, for which the tea is made softer with steam and shaped in a cloth before pressing. The final forms and images are attained by moulds and templates.
The following pictures show examples of variously formed Pu Erh tea and motive moulds.