A small‐scale rotary fermentation unit for rooibos tea

Abstract

A small-scale low-cost rotary unit was developed for batch fermentation of rooibos tea. Aeration of the fermenting tea was accomplished by periodic rotation. The performance of the unit was evaluated in terms of control of processing parameters and tea quality. Good control of the tea temperature was obtained and drying of the tea during fermentation was prevented. Rooibos tea with its characteristic sweet, honey-like flavour and red-brown extract colour was obtained after fermentation of the tea at 40ЊC with periodic aeration. Figure 1 A simplified flow diagram for the control of tea temperature and rotation frequency of the rotary fermentation unit for rooibos tea.

South African herbal teas: Aspalathus linearis, Cyclopia spp. and Athrixia phylicoides—A review

“…Batch rotary fermentation, a concept developed initially for rooibos fermentation (Joubert and Müller, 1997), but adopted by the honeybush industry, takes place at 70 • C for 60 h or 80-85 • C for 18 h. Drying either takes place in a rotary drier under controlled conditions or in the sun on drying racks.…”

Itinéraire du rooibos (thé rouge) en Afrique du Sud

“…Aujourd'hui, on préfère utiliser un artefact de précision : le thermomètre. Les expérimentations menées par les laboratoires montrent en effet que le seuil idéal de fermentation est atteint à 42°C (Joubert et Müller, 1997). Le processus de fermentation est donc stoppé lorsque le rooibos atteint cette température.…”

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

“…After bruising the moisture content was adjusted to 65% (wet basis) and fermented without delay. Fermentation was carried out with an experimental rotary unit (Joubert & Müller, 1997). A tray drier with cross-circulation of air at 2 m s Ϫ1 was used for controlled drying.…”