White tea is said to be the first type of tea to come into being, as it involves the least amount of processing. It appeared in old books as early as the Zhou dynasty (1046-256 BCE). White tea is usually made from a bud and one to two leaves. There are only two steps involved in white tea-making: withering, then drying of the tea leaves. Traditionally, the leaves are either put under the sun to wither naturally or withered in the shade for better control of oxidation levels, this process takes up to three days. Once the desired oxidation levels have been achieved, the leaves are further dried under the sun or roasted dry in ovens set at low temperatures. As there is only minimal processing involved, the quality of white tea very much depends on the quality of the tea leaves. As a general rule, good-quality white tea leaves are silvery and airy in appearance.