2.5.3. Black tea aroma

The most significant change that occurs during the manufacture of black tea is the conversion of colorless catechins to a complex mixture of yellow-orange to red-brown substances accompanied by the development of a large number of volatile compounds. The process was historically referred to as fermentation, but no microbiological processes take place.

Black tea aroma is a complex system of which more than 500 components have been identified. Some of the compounds that impart desirable flavour characteristics to black tea are: benzyl alcohol, dihydroactinodiolide, geraniol, cis-3-hexenyl hexanoate, b-ionone, cis-jasmone, linalool, linalool oxides, methyl salicylate, nerolidol, phenylacetaldehyde, 2- phenylethyl alcohol, 1-terpineol, theaspirone, a-damascone, etc.

Black tea aroma also contains the group of short-chain (5-7 carbon atoms), relatively undesirable aldehydes and alcohols that arise from lipid oxidation. Aroma quality is determined by the relative quantities of the two groups of components.