The Appearance of the Dried Leaves: Black tea have beautiful deeply dark leaves, which should be very tight and slim. The looser and coarser the leaves are, the lower the quality of the teas. You should also look for bright, dark leaves, and avoid old or faded tea leaves.
Observing the colour, knowing the skill: In addition, the liquor of the tea will show the effects of the fermentation. The well-fermented tea would produce a reddish liquor with yellow hue, while the poorly fermented tea would produce a brown liquor. Besides, the difference in colour was not only visible in the liquor, but it affects the brewed leaves too. As a matter of fact, there is an obvious difference in the constituents between the well-fermented tea and poorly fermented tea.
Evaluating Flavor and Aroma:You can also evaluate the quality of a black tea by enjoying the flavor and aroma .A high quality black tea will have a rich mellow flavor and aroma, with little to no astringency, with a deep black tea flavor. Lower quality black teas may taste bitter, or have little to no flavor, and may even possess a grassy smell which is not a good thing for a black tea to have.
Additionally, some low quality black teas may use artificial coloring to present the appearance of quality, and this causes the resulting tea to taste bitter and too light. If the tea contains artificial coloring, the appearance of the coloring on the leaves will not appear consistent.