Tea Production. The Journey of a Tea Leaf - Rivertea Blog
Carmen Rotaru | On 06, Feb 2013
It’s refreshing, it’s perfect for body, mind and soul, but have you ever wondered how does tea end up in your cup? Let’s discover together the tea production process from the fresh, green tea leaves to the perfect cup of tea.
It all starts with the tea plant also known as tea bush or for botanists, as Camellia Sinensis. Basically it’s the same plant for every cup of tea. Those other teas made from other plant materials, spices or flowers aren’t in fact real teas, but tisanes.
Tea only originates from this unique plant, Camellia Sinensis.There are two main varieties of the tea plant. One is the classic Camellia Sinensis plant which has its origins in China and features small leaves, the other is Camellia Assamica which originated in Assam, India and features broad leaves. There are also some hybrids between these two main varieties which are grown and used for our daily cup of tea. The story of tea production starts with the tea leaves and buds that are picked during the early and refreshing morning hours. Let’s discover together how the story continues.
Before talking about tea production process, I want to tell you a bit about the way teas are classified before ending up in our cups. Teas are classified according to region of origin. That means we distinguish between Chinese and Japanese teas, or between Indian or Indonesian teas, or between those coming from Taiwan and those from Ceylon, Sri Lanka.
As you have noticed, the Asian continent is the one responsible with tea production for two simple reasons. The tea plant originated in Asia and more specifically in China and the second reason refers to the climatological aspect. Only Asia has the perfect climate particularities for the tea plant to be growing and prospering.
There is also another classification made on regions of production, this time referring to smaller regions. We have the well know Darjeeling, also known as the “champagne of teas”, Assam and Nilgris, all coming from India. There are also Uva and Dimbula varieties coming from Sri Lanka, Keemun and Pu-erh are two examples from China or Enshu which is an example from Japan.
Regional classification isn’t the only one available for teas. Teas are also classified according to the size of the processed leaf. In the tea industry, tea leaf grading is the process of evaluating products based on the quality and condition of the tea leaves themselves. Traditional operations and processing of the tea leaves result in larger leafy grades (either hall leaves or large broken pieces) and smaller broken grades.
The large leaf grades are:
- orange pekoe (OP)
- flowery pekoe (FP)
- pekoe (P)
- pekoe souchong (PS)
- souchong (S).
The broken grades are:
- broken orange pekoe (BOP)
- broken pekoe (BP)
- BOP fanning
The highest grades are “orange pekoe”, and the lowest “fannings” or “dust”.
We haven’t still mentioned the most important classification of them all which is the classification based on the tea production process. There are four important categories of tea.
- Unfermented tea known as green tea
- Semifermented teas which are the oolong and the white tea varieties
- Fermented teas known as black teas
- Postfermented teas known as pu-erh tea.
The Processing of the Leaf Begins
The tea leaf goes through all kinds of stages in the tea production process in order to dry the leaf and to allow the chemical constituents of the leaf to produce their peculiar characteristics for each type of tea. The stages of the tea production process are:
1. Withering stage
2. Rolling stage
5. Sorting and Packing stages
The best-known compound of tea is caffeine which stimulates the mind, helps reduce the body fat and has an important role in giving the beverage its color, flavor and aroma. One cup of tea is estimated to contain between 60 to 90 milligrams of caffeine. The most important chemicals in tea are the tannins, or polyphenols, which are colorless, bitter-tasting substances that give the drink its astringency. When the polyphenols get oxidized they acquire a reddish color and form the flavoring compound of the beverage. There are also different volatile oils which contribute to the aroma of the beverage and also to its quality.
Only the fermented and postfermented teas go through all stages of the tea production process, which means that black and pu-erh teas take longer to produce. Green, white and oolong teas are differentiated by the variations in the important stage of fermentation.
#1 The Withering Stage
Only black and pu-erh teas go through the withering stage.
The withering process begins immediately after the leaves are plucked. The process intends for the leaves to lose the water they contain while being fresh. So, after the withering stage takes place, from 70% – 80% water composition only 55%-70% remains. The withering process also depends on what tea variety the producer wants to obtain.
The old traditional process required that the leaves were spread by hand in thin layers onto trays. The leaves were then allowed to wither for 18 up to 20 hours, depending on the temperature and humidity in the air and, of course, depending on size and moisture content of the leaf.
As the time passed and the technology evolved, so did this tea production stage, which is now accomplished by various mechanized systems. These systems reduced the withering time, but the drawback is that they can also lower the quality of the final product. The quality is reduced because the chemical withering time is reduced, lowering the caffeine and polyphenols composition in the tea leaves mechanically withered.
# 2 The Rolling Stage
This stage requires for the withered leaf to be distorted, thus acquiring the distinctive twist of the finished tea leaf, and while leaf are cells being burst, resulting in the mixing of enzymes with polyphenols.
The traditional method was simply to roll the leaves between hands or using one hand and the table until it was obtained a twisted version of the leaf and finally the leaves were broken into several pieces. Now the machines do all the tricks, enhancing the process.
After the leaves are rolled they are broken and sifted. The smaller leaves are being transferred in the fermentation room and what remains is getting rolled again. In many countries, rolling leaves has been abandoned in favor of distortion by a variety of machines. The nontraditional distorting machines can burst leaf cells so thoroughly that the withering stage becomes unnecessary. However, unlike traditional rolling, the machines do not produce the larger leafy grades of tea.
# 3 The Fermentation Stage
After the rolling process the fermentation kicks in, bringing the tea leaves one step closer to our cups. The rolled leaves are spread on tables of perforated aluminum trays under carefully controlled conditions of temperature, humidity and aeration.
The process isn’t exactly what we would call classical fermentation but a series of chemical reactions, the most important being the oxidation of the poliphenols compound. In traditional processing, optimum fermentation is reached after two to four hours. This time is extensively shorten by the use of machinery, carrying the leaves to the final process before packing, which is drying.
# 4 Drying the Tea Leaves
This process includes heat which inactivates the polyphenol enzymes and dries the leaf to a moisture content of about 3 percent. It also caramelizes sugars, thereby adding flavors to the finished product, and imparts the black color associated with fermented tea.
The traditional process meant that leaves were dried on large pans over fire, but after the industrialization of the 19th century, heated forced air has been used. Now the machinery does all the work. Modern innovations on the drier include the hot-feed drier, where hot air is supplied separately to the feeder to start immediately the drying, while the leaves are fed from the top on a series of descending conveyors.
We have to remember that green tea is not at all fermented which means that the oxidizing enzymes are killed by steam blasting the freshly plucked leaf in perforated drums or by roasting it in hot iron pans prior to rolling. The leaves are afterwards subjected to further heating and rolling until they turn dark green and take a bluish tint. The leaves are finally dried to a moisture content of 3 to 4 percent and are either crushed into pieces or ground to a powder.
The semifermented oolong tea undergoes a brief withering stage, the leaves being afterwards lightly rolled by hand until they get a red and fragrant appearance. The oolong tea leaves are then fermented about half the time allowed for black tea fermentation.
# 5 Sorting and packing stages
The first step when it comes to packaging is grading the processed tea leaves by size, shape and cleanliness. This is also done mechanically and some of the leaves undergo a second cutting stage in order to get a higher proportion of broken grades. The undesirable particles are removed either by hand or mechanically; it depends on the means of the producer.
After this selection, broken and sorted tea leaves are packed in airtight containers. This is done in order to prevent absorption of moisture which is the main cause of loss of flavor during storage. Packing chests are usually constructed of plywood, lined with aluminum foil and paper, and sealed with the same material.
Blended teas are sold to us, the consumers, as loose leaves tea. The loose tea is packed in corrugated paper cartons lined with aluminum foil, in metal tins, and in fancy packs such as metalized plastic sachets, or they are sold in tea bags made of special porous paper. Tea bags are mainly packed with broken-grade teas.
This is the amazing voyage of a tea leaf right down to our cup. The process takes time and has to be carefully supervised, because if fermented or dried too much or too little can result in damaging the quality and flavor of the tea. It’s like playing a musical instrument: if you know how to play, then a heavenly music will be the result of your effort, if you don’t know how to do it, then even your pet will run to your neighbors in order to save its hearing. Tea production is like making music, too much or too little of something and you end up with poor results.
We’ll soon launch our new incredible tasty tea blends. Join us, there are lots of special gifts waiting for you.