The blue color of this tea comes from a natural pigment called anthocyanin, which is found in many flowers and fruits. When the tea is brewed in hot water, the anthocyanins are extracted from the flowers and dissolve in the water, giving it a blue color. The pH level of the water can also affect the color of the tea. Acidic water will turn the tea a brighter blue, while alkaline water will turn it a darker blue. Some blue flower teas may also contain other ingredients, such as butterfly pea flowers, which can give the tea a deeper blue color.