Courtesy: Organic certification for tea
Pests that can afflict tea plants include mosquito bugs, genus Helopeltis, which are true bugs and not to be confused with dipterous insects of family Culicidae (‘mosquitos’). Mosquito bugs can damage leaves both by sucking plant materials, and by the laying of eggs (oviposition) within the plant. Spraying with synthetic insecticides may be deemed appropriate. Other pests are Lepidopteran leaf feeders and various tea diseases.
Production
Tea is mainly grown in Asia and Africa, though it is also grown in South America and around the Black and Caspian Seas. The four biggest tea-producing countries are China, India, Kenya and Sri Lanka, together representing 75% of world tea production. Smaller hubs of production include such places as São Miguel Island, Azores, in Portugal, and Guria, in Georgia. In 2020, global production of tea was 7.0 million tonnes, led by China with 42% and India with 20% of the world total. Kenya, Argentina, and Sri Lanka were secondary producers.
Storage
Storage conditions and type determine the shelf life of tea; that of black teas is greater than that of green teas. Some, such as flower teas, may last only a month or so. Others, such as pu-erh, improve with age. To remain fresh and prevent mold, tea needs to be stored away from heat, light, air, and moisture. Tea must be kept at room temperature in an air-tight container. Black tea in a bag within a sealed opaque canister may keep for two years. Green tea deteriorates more rapidly, usually in less than a year. Tightly rolled gunpowder tea leaves keep longer than the more open-leafed Chun Mee tea.
Storage life for all teas can be extended by using desiccant or oxygen-absorbing packets, vacuum sealing, or refrigeration in air-tight containers (except green tea, where discrete use of refrigeration or freezing is recommended and temperature variation kept to a minimum).
Tea is generally divided into categories based on how it is processed. At least six different types are produced:
- White: wilted and unoxidized;
- Yellow: unwilted and unoxidized but allowed to yellow;
- Green: unwilted and unoxidized;
- Oolong: wilted, bruised, and partially oxidized;
- Black: wilted, sometimes crushed, and fully oxidized (called 紅茶 [hóngchá], “red tea” in Chinese and other East Asian tea culture);
- Post-fermented (Dark): green tea that has been allowed to ferment/compost (called Pu’er if from the Yunnan district of South-Western China or 黑茶 [hēichá] “black tea” in Chinese tea culture).
After picking, the leaves of C. sinensis soon begin to wilt and oxidize unless immediately dried. An enzymatic oxidation process triggered by the plant’s intracellular enzymes causes the leaves to turn progressively darker as their chlorophyll breaks down and tannins are released. This darkening is stopped at a predetermined stage by heating, which deactivates the enzymes responsible. In the production of black teas, halting by heating is carried out simultaneously with drying. Without careful moisture and temperature control during manufacture and packaging, growth of undesired molds and bacteria may make tea unfit for consumption.