Effect of fermentation and drying conditions on the quality of rooibos tea

The effect of fermentation (30 degrees, 34 degrees, 38 degrees and 42 degrees C) and drying temperatures (40 degrees, 50 degrees, 60 degrees and 70 degrees C), as well as the effect of controlled drying as opposed to sun-drying on rooibos tea quality were investigated. The quality of rooibos tea improved with increasing fermentation temperature whereas quality decreased with increasing drying temperature (P < 0.05). No significant subjective quality difference between the two drying methods was obtained. Tea dried under controlled conditions was lighter in colour than sun-dried rooibos tea (P = 0.003) as indicated by higher L* values. The chromaticity parameters (a* and b*) were not significantly affected by drying under controlled conditions. Less chlorophyll was present in sun-dried tea than in tea dried under controlled conditions. The colour of tea prepared under experimental conditions was comparable with the colour of commercially-produced rooibos tea samples.