The tea plant is called Camellia Sinensis and, much like coffee, wine and all those other wonderful things, the flavour and characteristics of your tea vary by the soil, altitude and climate where the plant is grown, when it is picked and then how it is treated once harvested. It's an evergreen, tropical plant that takes three to five years to mature, if left wild will grow into a tree, but cultivated plants are pruned and grown as a bush for ease of plucking as well as promoting fresh shoots which provide new, tender leaves which are generally plucked every seven to fourteen days. It looks remarkably similar to our garden privet hedges.
Regardless of the variety of tea plant used, or where it is grown, tea leaves are then divided into categories based on when the leaves are picked and the level of processing ( oxidisation ) allowed after harvesting. This then determines whether a tea is white, green, oolong or black. As a general rule, the more tea leaves are processed, the stronger the flavor.
Starting with the leaves that essentially have the least done to them, white tea is the lightest and most delicate variety. The youngest, freshest leaves are simply plucked and dried, so there’s no time for oxidation. This lack of processing means that the natural health benefits of the leaves are fully retained. Tasting notes lean towards being delicate or sweet.
With green tea the leaves are picked then laid out to wither then, but before the oxidation process really starts, the leaves are steamed or pan -fired and is then rolled . This prevents the veins in the leaf breaking before rolling so that minimal oxidation of the leaf occurs. The leaf is then dried and will have retained most of their colour, kept most of their natural goodness. Tasting notes being lightly toasted or grassy.
Black tea leaves will go through more processes in that, after the leaves have been withered they are then broken up or rolled and laid out exposed to the air. After a few hours the leaves turn a golden russet colour and oxidisation is complete. This process does mean that black leaf tea will have less of the nutrition benefits are retained, but in return we have this great amber brew, rich and full-bodied.
On to Oolong tea. Occuying the middle ground between green and black tea, it follows the same process as black tea, but the oxidisation varies hugely. Longer oxidization results in a darker oolong which is more similar in taste to a black tea, while shorter oxidization makes it more similar in nature to green tea. It can produce a reddish brown leaf that can still be a little green in the middle or it can produce a very green leaf, dependent on the amount of oxidisation. Generally it brews a light golden colour and can be very delicate.