Boltzmann-Based Empirical Model to Calculate Volume Loss during Spirit Ageing

Abstract

The Boltzmann equation is applied to fit data of volume loss for evaporation (in %) during spirit ageing in northern white oak (Quercus Alba) standard barrels of 205 L (+/− 10 L) using a temperature and humidity controlled cellar. The Boltzmann equation satisfactory fitted to the experimental data of the volume loss against temperature at constant humidity. Two parameters of the Boltzmann equation showed a linear dependency on the relative humidity of the air, while the other two parameters exhibited a constant value independently of the air humidity. The found empirical mathematical model can be used to calculate the volume loss for evaporation of spirits (40% v/v of ethanol) during ageing in terms of relative humidity (range: 40%–95%) and temperature (range: 10–30 °C) with significant accuracy.

Optimized Criterion Based on the Surface Area to Volume Ratio for Wood Casks Re-Filling Time Calculation During Long-Term Rum Maturation Process

“…In addition, as extensively reported [2,[14][15][16][17][18][19][20][21][22][23][24][25][26], the change of…”

“…The volume loss is an intrinsic part of the ageing process. As previously described, the barrel acts as a semi-permeable membrane that allows evaporation from the cask and migration of air into the barrel, because of its porous structure [2].…”

“…The evaporation loss during the ageing process is an indubitable economic concern for spirit producers. Therefore, efforts to diminish and/or control the loss during ageing are crucial in order to optimize the production process and to reduce the associated costs [2].…”

“…Two variables are fundamental in the ageing process: the ageing time and the quality of the barrel wood. Barrels are directly involved in the produced changes on rum's composition due to the transfer of oxygen and phenolic and aromatic compounds from wood to rum [1][2][3][4][5][6][7][8][9][10][11]. Barrels have another important function than those of serving as a container.…”

“…Despite its many advantages, natural ageing in barrels has several drawbacks. Barrels are expensive to produce, have limited lifetime and generate a significant volume loss due to liquid evaporation [2]. The blends of spirits and the different base rums used in each of the stages of the ageing process, carried out under the guidance of the Cuban rum master, are decisive in achieving the finished rum with proper sensory characteristic balance of taste, color and aromas.…”