Determination of a kinetic factor influencing the vaporescence of flavour components from wort

Abstract

The current article considers the question of whether vaporescence during wort boiling affects evaporation via the vapour side mass transport. Thereby the vaporization of unwanted flavour components (such as dimethyl sulphide or benzaldehyde) can be influenced negatively or positively, which affects the amount of energy needed. The question is pursued by pre-calculation and experimental validation of the vapour side mass stream at the evaporation surface: for that purpose vaporescence trials were carried out in a plant trial, with both benzaldehyde and water as pure substances and a mixture of benzaldehyde and water in an infinite solution (xi<10-6). Trial parameters were process temperature and volume stream of the gas phase. The results obtained by the trials with pure substances enable pre-calculation of vapour side mass transport. Then, pre-calculation is compared with the results of the mixture trials and thus verified. As a result it has to be stated that vaporescence in the brew houses is pre-calculable and that the mass transport has an impact on the vaporescence at the vapour side boundary layer.