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Traditionally manufactured in China and Taiwan, oolong is a semi-oxidised tea combining the best qualities from black and green teas. In order to give a rich flavour, fresh shoots with one new bud and three leaves are gathered and are immediately processed. Initially, the leaves are wilted in warm air, and then they are shaken in bamboo baskets so that the edges of the leaves become slightly bruised. This means that there will be a certain amount of oxidation during subsequent processing. The most important stage of production is to discern the exact moment necessary to cease further fermentation, which is done by rapidly heating tea leaves that have undergone sufficient oxidation. The temperature used is higher than for other types of tea. Furthermore, rolling takes place in order to release the aroma and flavour. Finally, the tea is dried over charcoal stoves.
There are three basic kinds of oolong teas – dark open-leafed oolongs that are 60 - 70% oxidised, greener balled oolongs also known as jade oolongs, which are 20 – 30% oxidised, and baked or amber oolongs.
As for health benefits, oolong protects and strengthens the activity of the heart, and supports the circulatory, digestion and immune systems. Like other teas, oolong is full of antioxidants and the vitamins B2, C and E.