EFFECT OF CONTROLLED CONDITIONS DURING DEEP BED FERMENTATION AND DRYING ON ROOIBOS TEA (ASPALATHUS LINEARIS) QUALITY

Small-scale processing of rooibos tea was achieved under controlled conditions of bruising, fermentation and drying. The effects of aeration, fermentation time, fermentation temperature and drying method on rooibos quality were investigated, using plant material that was stored at −30C after harvesting and comminution. Adequate aeration significantly improved rooibos quality. Overall quality improved significantly with increasing fermentation time, mainly due to an improvement in taste. Fermentation temperature did not affect quality significantly. Freezing of the plant material before processing was detrimental to quality, resulting in some instances in a Standard grade infusion with a grassy aroma and an astringent taste that is indicative of under-fermented rooibos. Choice grade rooibos with a flat, "thin" taste and a poorly developed sweet aroma was obtained in a few cases. The drying method (deep bed versus thin layer) did not affect overall quality significantly.