Batch distillation of spirits: experimental study and simulation of the behaviour of volatile aroma compounds

This paper focuses on the behaviour of volatile compounds during batch distillation of wine or low wine, in traditional Charentais copper stills, heated with a direct open flame at laboratory (600 L) and industrial (2500 L) scale. Sixty-nine volatile compounds plus ethanol were analysed during the low wine distillation in the 600 L alembic still. Forty-four were quantified and classified according to their concentration profile in the distillate over time and compared with previous studies. Based on the online recording of volume flow, density and temperature of the distillate with a Coriolis flowmeter, distillation was simulated with ProSim® BatchColumn software. Twenty-six volatile compounds were taken into account, using the coefficients of the ‘Non-Random Two Liquids’ model. The concentration profiles of 18 compounds were accurately represented, with slight differences in the maximum concentration for seven species together with a single compound that was poorly represented. The distribution of the volatile compounds in the four distillate fractions (heads, heart, seconds and tails) was well estimated by simulation. Finally, data from wine and low wine distillations in the large-scale alembic still (2500 L) were correctly simulated, suggesting that it was possible to adjust the simulation parameters with the Coriolis flowmeter recording and represent the concentration profiles of most of the quantifiable volatile compounds. © 2019 The Institute of Brewing & Distilling