What are the two important sensory indicators of black tea

The golden ring and the turbidity after cooling. There should be a golden ring on the inner wall of the teacup; the thicker the golden ring and stronger the color, the better the tea. The turbidity after cooling refers to the fact that the tea liquid is clear when brewing in the British teapots, but becomes turbid after cooling down and the turbidity disappears when the liquid is heated again. The turbidity after cooling is an indicator that the black tea liquid contains rich substances.