All of the world's tea falls into one of three categories: black, oolong or green. These divisions are based solely on differences in the methods of processing the tea leaf. Black teas (most familiar in the West) are black in appearance and produce red-brown liquor in the cup. Green teas are green in appearance and yield yellow-green liquors. Oolong teas are greenish-brown in appearance and make an amber-colored beverage. It is possible to make green, black and oolong teas from the leaves of a single tea bush. It is commonplace for greens, oolongs and black teas to be made from the same varieties of the plant. As a practical matter, however, certain districts, areas, and estates generally specialize in the production of one of these categories of tea. Virtually all Japanese tea is green while almost all Indian tea is black. China produces all three types.
Black Tea Processing
Black Tea starts as green tea. The green leaves are withered after picking, spread on racks to dry out, and then rolled and crushed to release the leaf's juices, which then oxidize and turn the leaves brown.
Withering
The leaves are thinly spread to wither either naturally (where the climate is suitable), or by means of heated air forced over the withering racks. The object is to evaporate as much of the tea leaf's water content so that the leaf becomes pliable like soft leather gloves.
Rolling
From the withering-racks the soft, green leaf passes to the rolling machinery where it is twisted and rolled to break up the leaf cells and release the juices which give the tea its flavor. The first important chemical change starts here when the juices, which remain on the leaf, are exposed to the air. At this point development of the essential oil begins.
Roll breaking
From the roller, the tea emerges as twisted lumps which are broken up by coarse mesh sieves or roll-breakers. The fine leaves which fall through are then taken to the fermenting rooms, while the coarse leaves are returned for further rolling.
Oxidation or fermenting
The oxidation that started in the rollers is completed in the fermenting room. Here the tea leaves are spread on cement or tile floors (sometimes glass or cement tables) in a cool, damp atmosphere. The leaves undergo further chemical change through the absorption of oxygen, and turn a bright copper color, similar to a new penny. It is this process of oxidation which distinguishes the black teas, almost exclusively drunk in the United States today, from what are known as green teas.
Drying or firing
The purpose of this is to arrest further oxidation, and to dry the leaf evenly and thoroughly without scorching it. The automatic tea drier consists of a large iron box. Inside, the leaves which are spread on trays, travel slowly from top to bottom while a continuous blast of hot dry air is forced into the box. Careful regulation of the temperature and the speed at which the trays move is the main factor in successful firing.
Green Tea Processing
Green tea undergoes the least elaborate processing. Once picked, green tea does not receive a withering treatment. It is put into a large "steamer" and heated. This softens the leaves for rolling and keeps the juices from oxidizing. The leaves are rolled and dried until they are crisp. They remain green and contain caffeine.
Other Teas
Oolong tea is a compromise between black and green tea. The green leaves are allowed to turn partially brown before drying, so that oolongs share some of the taste characteristics of both green and black teas.
Flavored teas are generally blends of tea containing natural, artificial, and raw materials found in nature.
Tisanes are fruit teas that do not contain an actual tea leaf. Tisanes get their flavor from scented oils and the different fruits that make up the blend
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