## 2 Results and Discussion
### Influence of SCC Distillation on Wine Composition  
The basic composition (i.e., alcohol, residual sugar, pH, titratable acidity (TA), volatile acidity (VA), malic acid, wine color and hue, and total phenolics measurements) of wine and stripped wine are reported in Table 1. As expected, SCC distillation resulted in the progressive removal of ethanol, such that the initial alcohol concentrations of ShS and PVS wines (15.1 and 14.2% alcohol by volume (abv), respectively) were reduced to 0.3% abv in the corresponding 29% stripped wines (Table 1). Small changes in residual sugar (\(\leq\)0.2 g/L) and pH (0.2) were observed, but were not considered to be meaningful from a sensory perspective. Similarly, small changes in VA, from 0.53 to 0.48 g/L for ShS and 0.36 to 0.48 g/L for PVS, were not considered to be significant. However, concentration of non-volatile organic acids, anthocyanins and tannins resulted in substantial increases in TA, malic acid (for ShS), wine color and total phenolics following 29% stripping; typically 30-40% increases were observed, (approximating the degree of concentration achieved via SCC treatment). Wine hue was not affected. Only small changes in volatile phenol concentrations (i.e., \(\leq\)5 g/L) were observed in stripped wines following SCC distillation (Table 2). Guaiacol concentrations initially increased (by 1-4 g/L) with 1 and 13-14% stripping, but decreased by 3 and 5 g/L (relative to untreated ShS and PVS wines) following 29% stripping. In contrast, syringol concentrations increased by 5 and 2 g/L for SCC treatment of ShS and PVS wines, respectively. The concentrations of other volatile phenols changed by \(\leq\)1 g/L following 29% stripping (Table 2), with the exception of \(o\)-cresol, which decreased by 2 g/L, and \(p\)-cresol, which increased by 2 g/L, following 29% stripping of ShS. Increases in volatile phenol levels reflect concentration due to the removal of ethanol and water [39], whereas decreases suggest volatile phenol removal. This was evident when changes in guaiacol and syringol concentration (and their rutinoside and gentiobioside) were compared with concentrations predicted in stripped wine as a consequence of changes in volume (i.e., accounting for concentration due to removal of 1%, 13-14% and 29% of the initial wine volume, with SCC treatment). Measured guaiacol concentrations initially followed predicted concentrations,but deviated as SCC treatment progressed (Figure S1), indicating partial removal of guaiacol. In the case of syringol, guaiacol rutinoside and syringol gentiobioside, measured and predicted concentrations were comparable (Figure S1), confirming their retention (and concentration) in stripped wine. The relative removal and/or concentration of volatile phenols (in free and glycosylated forms) during SCC treatment is also apparent when the composition of condensate fractions are considered (Table 2). Guaiacol was detected in all ShS and PVS condensate fractions, with concentrations increasing as a function of the degree of stripping; i.e., from 30 and 35 \(\mu\)g/L after 1% stripping to 80 and 65 \(\mu\)g/L after 29% stripping (of ShS and PVS, respectively). Significantly lower levels of 4-methylguaiacol and \(\circ\)-, \(m\)- and \(p\)-cresols were present in condensates, i.e., 5-10 \(\mu\)g/L, predominantly in condensate collected after 13-14% and/or 29% stripping, whereas syringol and 4-methylsyringol were not detected in any condensate fractions. The volatile phenol composition of condensate fractions can be explained by differences in volatility (Table S1). Of the volatile phenols measured, syringol and 4-methylsyringol have the highest boiling points (260 and 268 \({}^{\circ}\)C) and lowest vapor pressures (0.006 and 0.005 mm Hg at 25 \({}^{\circ}\)C). As such, they are not extracted during SCC distillation, even at higher stripping rates. In contrast, guaiacol has the highest vapor pressure (0.179 mm Hg at 25 \({}^{\circ}\)C), and is therefore extracted from wine to a greater extent than 4-methylguaiacol and the cresols.