Influence of still design and modelling of the behaviour of volatile terpenes in an artificial model gin

Behaviour of volatile compounds in gin distillation using a batch column laboratory still has been investigated altering distillation parameters such as reflux strategy, pressure, and still design (column configuration). The distillate was separated into four equal fractions and ten volatile terpenes were quantified. Experimental values were compared to calculated data using a dynamic model calculated with ProSim BatchColumn software using a non-random two-liquid model to describe the interaction between solvents and terpenes. In the simulation different terpenes were considered and clustered into three group profiles. The monoterpene group was found to be the most volatile resulting in the highest concentration in the first fraction and depleting towards the end. The oxygenated terpenes increased in concentration with depleting ethanol concentration in the still and were therefore the least volatile compounds whereas the two representatives of the sesquiterpenes were found to be semi volatile. Changes in the column configuration resulted in major differences in the total concentration of terpenes extracted. The change of reflux strategy resulted in a higher concentration of the more volatile fraction at the higher reflux ratio chosen. The model showed a moderate agreement with the experimental data and only the monoterpenes considered showed good agreement.