The family Theaceae is an extremely diverse family containing 28 genera and in excess of 520 species (RHS Index of Garden Plants). Some of the genera in this family include Gordonia Ternstromia, Steartia and Franklinia. The genus Camellia, a member of the family Theaceae, has 267 species nowadays (international Camellia Register) – difficult to believe considering that there were only two species named in 1735 (C. japonica and C. sinensis).
Surprisingly, few people know that tea, one of the world’s most popular drinks, is made from Camellia sinensis. There are two main varieties used: Camellia sinensis var. assamica (black tea) and Camellia sinensis var. sinensis (green tea).
These prefer different climates—var. assamica is better suited to warmer climates whereas var. sinensis is better suited to the cooler southern regions. They like the same conditions as many other camellias, namely acidic soils, good drainage and full sun (in the cooler areas). Generally they are hardy, attractive shrubs, flowering generally around mid September, depending upon locations.
Green Tea versus Black Tea
So what really is the difference between green tea and black tea? While it is known that Camellia sinensis var. assamica is used most commonly for black tea and that Camellia sinensis var. sinensis is used primarily for green tea, this is not the main difference between the two. The real difference is in the processing. While I am not an authority on tea manufacture or processing, in a nutshell – black tea goes through fermentation and drying processes that give the tea its distinct colour.
Green tea, on the other hand, is harvested and quickly steamed. This process halts the oxidation and preserves the nice green colour of the leaves. The tea is then heated and rolled through a series of processes before drying. It is know that this rapid steaming process preserves the largest amount of antioxidants in the leaf and these are the special chemicals which are believed, by many, to be so health-giving. The machinery used for this process can be very elaborate and large in size.
Why is Green Tea so Good for Health?
The chemicals know to occur in green tea have been shown to provide protection against respiratory and digestive infections and food poisoning. Furthermore, they have also been shown to significantly lower blood pressure and possess anti-mutagenic activity. Additionally, at very high levels, green tea catechins reduced cholesterol in animal studies.
Green tea blocks the attachment of bacteria to the teeth, protecting against cavities. Green tea extract is non-toxic, both in acute doses and high long-term doses. There is no potential for causing mutation or birth defects, and no adverse effects on fertility, pregnancy or nursing.
How is Green Tea Grown and Harvested?
Propagation of green tea is relatively simple—semi-hardwood cuttings are used much the same as those used for C. sasanqua or C. japonica. Propagation houses need only be simple. A well-drained mix and good ventilation will certainly help.
Once propagated cuttings can be planted by hand, but when you need 10,000 – 20,000 plants per hectare, mechanical planters are often used.
Green tea is grown as a low hedge-row which is immaculately maintained and cultivated. In Japan, the tea plantations are carved into every available inch of space. Nothing is left to chance in the growing process as the quality of the tea is dependent on many things including leaf colour, nitrogen content and the absence of any leaf damage.
Harvesting is done with finely tuned machines which are specially designed to remove only the topmost 2 – 3 leaves from the actively growing plant.
Potted plants of Camellia sinensis are increasingly hard to find. The ‘ornamental’ varieties are generally referred to as ‘pink tea’ and ‘white tea’ according to flower colour. These ‘ornamental’ types are probably well suited to tea production, however they are not the varieties which are commonly used for commercial Japanese-style green tea production.
How is Green Tea Used and Sold?
In Australia there are many different green tea products on the market, but few compare with well-brewed traditional Japanese style green tea (remember that Japan imported the original plants from China). Nowadays in Japan you get just about anything with a ‘green-tea’ infusion from ice-cream to biscuits and everything in between as well as a very nice traditional green tea cuppa.
What is happening with the Industry in Australia?
Green tea production is under way in New South Wales, Victoria and Western Australia.
By John Robb, NSW Camellia Research Society, published in Camellia News 174, Winter 2007, p 14.