Purple Leaf "Zi Cha" Pu-erh Tea
During the hot, humid summer and fall seasons a portion of tea tree buds are purplish red colored. The source of the color is anthocyanin, which changes color along with cell sap acidity. High levels of acidity lead to red color, while medium acidity is more purple, and high alkalinity tends toward indigo. Purplish red tea results from an inherited reaction to unfavorable hot and humid summer environmental conditions, providing the tea tree with a mechanism for fighting scorching ultraviolet rays.