The tea plant, an evergreen shrub going by the scientific name canellia sinensis was originally indigenous to China, Tibet and northern India. all the varieties of tea available today come from a few strains of the same plant. As we will see, different varieties of tea come from how the leaves are dried and processed. First, we'll look at how the plants are grown.
Tea can be grown in almost any climate but is grown commercially in tropical and subtropical areas. India, China, Sri Lanka, East Africa and parts of South America are among the primary tea producers. Tea is commonly grown in mountainous regions below 6,000 feet. Altitude and mountain mists help protect against too much sun and give the right temperature and humidity to let the buds grow slowly and stay tender.
Harvesting tea is still very labor intensive. Despite advancements in the mechanized harvesting of other crops, tea is still harvested by hand. Harvesting tea leaves, known as plucking, is done when the tea plant sends forth tender new leaves and unopened buds. An even pluck is very important. Harvested leaves must be the same size so they can dry uniformly.
When the leaves are ready to be picked, the tea grower must make a decision that will affect the quality of his harvest. He must decide if he wants a large amount of ordinary tea or a small amount of good to fine tea. When leaves are plucked from the tree, that pluck can be described as normal, fine, or coarse. This depends on how many leaves are taken from the bush and how long the leaves are allowed to brow between pluckings.
Normal plucking consists of two leaves and a bud, producing average to good tea. In fine plucking fewer leaves are taken, producing better tea. In coarse plucking, extra leaves are taken, producing poor to average tea. Harvesting varies from country to country according to periods of flushing which depend on climate and altitude. So, the aspects of tea production most associated with quality tea are soil and water supply, high elevations, young leaves and a favourable plucking season.
This brings us to the production of dried tea leaves. The basic steps in this process are withering, rolling, fermentation and firing. The chief differences between green, black and oolong teas are which steps are omitted and which are shortened.
Making tea from freshly picked leaves would be harsh and thin, nothing like tea made from the final product. First, leaves are dried until they've lost up to 80% of their water content. This makes the leaves limp enough to be rolled without cracking or tearing. Withering can take from 10 to 24 hours, depending on desired results.
The next step is rolling. The purpose of rolling is to bruise the leaves which brings together catechins and polyphenol oxidase. Release of these and other chemicals aid in the oxidation process and help develop tea's flavor. Once done by hand, rolling is now done by machine. During the rolling process oxidation starts, heat is generated and moisture remaining in the leaves begin developing the tea's essential oils and juices. Rolling also twists the leaves which allows the teas to infuse more efficiently and produce a more flavorful brew.
The next part of the process is fermentation during which the crushed and twisted leaves go through a final chemical process to produce the finished tea. The leaves are spread out on the floor for a few hours until they turn bright copper. The oxidation that occurs during this process is responsible for tea's flavor, strength and body. Fermentation also allows tannins to develop. A shorter fermentation results in a more pungent tea whereas longer fermentation gives a more flavorful tea with deeper color.
When the tea has finished fermenting, it goes through a process called firing where it is exposed to a blast of hot, dry air. Firing ends the fermentation process by killing the enzymes and bacteria responsible for oxidizing the tea leaves. The hot air passes through enclosed chambers which the tea is sent through in trays. The firing process must be carefully controlled. If leaves are fired too quickly, they harden on the outside, remaining moist on the inside and are susceptible to mould. under firing will stew the leaves rather than dry them and will result in over-fermented leaves.
Finally, when the leaves have been fired its time for them to be graded. When leaves emerge from the drier there are large, small, broken and unbroken leaves mixed together. They can't go to market like this because they won't infuse at the same rate and make a good cup of tea. So, the leaves get passed through sieves with progressively smaller holes to trap leaves of different sizes.
One final word about the processing of different styles of tea. I said before that the main difference between different styles of tea comes down to how they are processed. Black tea for example, goes through the whole process described above. Green tea is not withered before being fired. Instead they are alternatively rolled and fired until a final product is reached. Oolong tea is slightly withered, fermented, fired, rolled, briefly fermented and re-fired.
From here, tea is packaged, shipped and purchased. Being such a labor intensive process, it's easy to see why quality tea can be somewhat expensive. However, when you enjoy a nice cup of tea, its easy to see that sometimes, a hands on approach can be the best way to go.
