1, black goji berries in weakly acidic water (tap water), brewing is blue, in weakly alkaline water (mineral water), brewing is purple, high concentration is black.

2, black goji berries in hot water in favor of purple, cool water in favor of blue. This is due to the phenomenon of anthocyanin dissolved in water.

3, if it is true that the black goji berries that you are in the weak acid in cold water.

4, it is recommended to soak black goji berries with alkaline water, because the human stomach is acidic. And alkaline water is better for humans than acidic water.