This work presents the application of a differential distillation model for the simulation of cachaça production in a pot still (alembic). The vapor–liquid equilibria of the multicomponent mixture were described in a rigorous way, using the nonrandom two‐liquid model for the liquid phase activity coefficients and the virial equation with the chemical theory for the vapor phase fugacity coefficients. Two experimental trials were performed in order to validate the simulation results. The boiling points of the wine and the ethanol concentration of the distillate were measured at fixed time intervals. The concentrations of acetaldehyde, ethyl acetate, methanol, n‐propanol, isobutanol and isoamyl alcohol, and the volatile acidity were analyzed in the head, heart and tail fractions of the distillate. In general, a good agreement was achieved between the experimental and the simulation results, in terms of the temperature and the alcoholic graduation profiles, and also a satisfactory similitude in terms of the concentrations of the main congeners.
PRACTICAL APPLICATIONS
Spirit's sensorial quality depends on the ethanol and main congener concentrations, which should be controlled by dividing the distillate in appropriate cuts (head, heart and tail fractions) during the distillation. A correct simulation procedure of the pot still distillation allows improving the policy of distillate cuts, considering the product quality, the maximal recovery of ethanol in the heart fraction (spirit) and the energy consumption. It can as well help to define a policy of distillate cuts more appropriate to different types of wine, i.e., wines containing, for instance, larger concentrations of light components (acetaldehyde, methanol, etc.), or of those containing larger contents of heavy compounds, such as acetic acid. So this work goal was to indicate that computational simulation, based on a careful modeling of the system, could be an important tool to investigate the effect of processing variables in the final product quality, also in terms of minor compounds.