The manufacturing procedures of spirits in the world such as whisky, brandy, rum, vodka, cachaça, and Chinese spirits are constituted of three consecutive processes: fermentation, distillation and ageing. For these processes, distillation process is closely correlated with the quality and yield of the raw spirit. Alembic stills and column stills are applied to the distillation of brandy, whisky, and cachaça. The former has no trays or appreciable reflux and requires multiple distillation to achieve high-proof raw spirits, while the latter has a reflux column to decreases the concentration of the congeners in raw spirits (Claus and Berglund, 2005). A distinct device called as Zeng-tong (Li et al., 2012) has been widely applied to the distillation of Chinese spirits for a long history. The Zeng-tong is composed of reboiler, taper barrel, condenser and other attachments, such as stream pipes, lid and tube type heat exchanger (shown in Figure 1A). Similar to fruit brandy (Claus and Berglund, 2005), the operation mode of Chinese spirits belongs to a batch distillation. The main production process of Chinese spirits is as follows ( Figure 1B). Prior to the spirit distillation, the fresh grains and grain hull are mixed with the fermented grains to adjust
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