Tea Processing

Major Processing Options

*non-oxidized (Green)
*semi-oxidized (Oolong)
*fully oxidized (Black)

Green Tea Processing

*Harvesting: harvest leaf to meet processing requirements
*Steaming: leaf steamed to kill oxidizing enzyme
*First Drying Roller: stirred/dried from 75% to 50% moisture
*Rolling: leaf cell broken and moisture equilibrated
*Second Dry Roller: tea rolled and dried to 30% moisture
*Third Dry Roller: tea pressed and dried to 13% moisture
*Drying: tea uniformly dried to 6% moisture
*Refining: crude tea dried (< 4%), sifted, classified

Black Tea Processing

*Harvesting: harvest leaf to meet processing requirements
*Withering: physically and chemically prepares leaf
*Rolling: trigger "oxidation"/desired physical property
*Oxidation: flavor and color development
*Firing/Drying: terminates "oxidation" process
*Sorting: removal of stalk, classification of final product

Determinants of Tea Quality

*Tea Bushes (Genetics, Age, Health)
*Environment (Climate, Soil, Pests)
*Seasonality
*Farming Practices (Irrigation, Fertilization)
*Harvesting Practices
*Processing Methods
*Storage & Transport Conditions
*Age of the Tea (After Manufacturing)

How is Tea Produced?
The first step in tea production is the harvest. Most harvesting is still done by hand which is very labor-intensive. Some growers have had success using a machine that acts much like a vacuum cleaner, sucking the leaves off the branch. The latter method is used for the cheaper varieties of tea, as it is not capable of discriminating between the high-quality tip leaves and the coarser leaves toward the bottom of the branch.

On an estate, each picker is credited with their own weights of tea for subsequent payment. A skilled picker can gather up to between 30-35 kilograms of plucked leaves in a day, sufficient to produce about 7.5 to 9 kg of processed black tea. As black tea has the major share of the tea market in terms of production, sales and amounts consumed, most tea factories produce black tea. On arrival at the factory, the plucked leaves are spread on vast trays or racks, normally placed at the top of the factory, and are left to wither in air at 80 - 90 degrees. The moisture in the leaves evaporates in the warm air leaving the leaves flaccid. This process can take between 10 to 16 hours, depending on the wetness of the leaves. Some factories will gently hasten the process with the aid of warm air fans.

The harvested leaves can be processed in two ways: CTC or Orthodox. CTC, which stands for "crush, tear, curl," is used primarily for lower-quality leaves. CTC processing is done by machine; its name is actually fairly descriptive. The machines rapidly compress withered tea leaves, forcing out most of their sap; they then tear the leaves and curl them tightly into balls that look something like instant coffee crystals. The leaves are then "fired," or dehydrated. Most tea connoisseurs are not very interested in CTC tea, since this process does not allow for the careful treatment that high-quality leaves merit. But CTC has an important and legitimate role in the tea industry. Because it is a mechanized process, it allows for the rapid processing of a high volume of leaves which otherwise would go to waste. It is also good for producing a strong, robust flavor from leaves of middling quality; in fact, for many varieties of leaf CTC is the preferred processing method.

The Orthodox method is a bit more complex, and is usually done mostly by hand. The process differs for black, green and oolong teas. The basic steps in the production of black tea are withering, rolling, oxidation, and firing. First, the leaves are spread out in the open (preferably in the shade) until they wither and become limp. This is done so that they can be rolled without breaking. Rolling is the next step. This is rarely done by hand any more; it is more often done by machine. Rolling helps mix together a variety of chemicals found naturally within the leaves, enhancing oxidation. After rolling, the clumped leaves are broken up and set to oxidize. Oxidation, which starts during rolling, is allowed to proceed for an amount of time that depends on the variety of leaf. Longer oxidation usually produces a less flavorful but more pungent tea. Many texts refer to the oxidation process by the misleading term "fermentation." However traditional and evocative the term may be, it is best avoided. Oxidation of tea leaves is a purely chemical process and has nothing to do with the yeast-based fermentation that produces bread or beer. Finally, the leaves are heated, or "fired," to end the oxidation process and dehydrate them so that they can be stored. Oolong is produced just like black tea, except that the leaves are oxidized for less time. Green tea is not oxidized at all. Some varieties are not even withered, but are simply harvested, fired, and shipped out.

Factory tea-tasters will taste the finished make to ensure that no mistakes have been made during the manufacture or that the tea has not been contaminated by anything else inadvertently. Samples of the "make" are sent to selling brokers worldwide. All brokers will evaluate the tea for quality and price, reporting back to the estate or cooperative so the tea can be sold to the best advantage. After each make the tea factory is washed from top to bottom to ensure that the completed make does not contaminate the next make of tea.

Many consumers often have little concept of the long and arduous journey the leaves make from the time they are first cultivated to the moment they are enjoyed in a cup. Tea must be grown in a healthy environment, harvested by skilled pickers, carefully processed, graded by experts, then packed and shipped to the exporter or importer. This over simplified version does not even begin to tell the whole story. How does a single tea shipment make it from the plantations of a country such as Sri Lanka into the hands of a tea wholesaler or retailer in the United States? One needs to follow the production story played out in tea plantations throughout the world to appreciate the complexity of the journey.