these teas are grown in taiwan (formerly formosa), where the climate is perfect for tea growing; the humidity is 92 percent for most of the year. oolong tea is semi-fermented. It has the taste and colour of half-green, half-black tea. the use of the whole tea leaf produces a pungent, fruity taste. low in caffeine, this tea is smoother than black tea but less fresh-tasting than green tea. this is the tea that many claim aids weightloss.