# Experimental Whisky Fermentations: Influence of
## 3 Results
### Effect of Filtration on Wort Quality
\begin{table}
\begin{tabular}{c c c c c} \hline  & **Control** & **Filtered** & **Boiled** & **Autoclaved** \\ \hline FG (\({}^{\circ}\)) & 1000.7 \(\pm\) 0.8 \({}^{\circ}\) & 1015.3 \(\pm\) 0.8 \({}^{\rm a}\) & 1005.3 \(\pm\) 0.6 \({}^{\rm b}\) & 1005.4 \(\pm\) 0.2 \({}^{\rm b}\) \\ \hline pH & 3.90 \(\pm\) 0.00 \({}^{\rm b}\) & 3.75 \(\pm\) 0.04 \({}^{\rm c}\) & 4.54 \(\pm\) 0.00 \({}^{\rm a}\) & 4.56 \(\pm\) 0.01 \({}^{\rm a}\) \\ \hline ABV (\%) & 9.2 \(\pm\) 0.1 \({}^{\rm a}\) & 7.2 \(\pm\) 0 \({}^{\rm c}\) & 8.4 \(\pm\) 0 \({}^{\rm b}\) & 8.5 \(\pm\) 0 \({}^{\rm b}\) \\ \hline End of lag phase (h) & 7.6 \(\pm\) 0.1 \({}^{\rm b}\) & 8.03 \(\pm\) 0.15 \({}^{\rm a}\) & 7.63 \(\pm\) 0.05 \({}^{\rm b}\) & 7.63 \(\pm\) 0.15 \({}^{\rm b}\) \\ \hline Vmax (h) & 13 \(\pm\) 0.08 \({}^{\rm b}\) & 14.94 \(\pm\) 1.1 \({}^{\rm a}\) & 13.44 \(\pm\) 0.17 \({}^{\rm b}\) & 13.64 \(\pm\) 0.19 \({}^{\rm a}\) \\ \hline Start of stationary phase & 19.69 \(\pm\) 0.04 \({}^{\rm c}\) & 22.33 \(\pm\) 0.25 \({}^{\rm a}\) & 19.11 \(\pm\) 0.29 \({}^{\rm c}\) & 21.33 \(\pm\) 0.36 \({}^{\rm b}\) \\ \hline Cumulative CO\({}_{2}\) production (mL/100 mL) & 3332.82 \(\pm\) 56.52 \({}^{\rm a}\) & 2563.09 \(\pm\) 27.65 \({}^{\rm c}\) & 3095.57 \(\pm\) 36.94 \({}^{\rm b}\) & 3225.02 \(\pm\) 153.01 \({}^{\rm a,b}\) \\ \hline Total count (Count/mL) & 1.00 \(\times\) 10\({}^{8}\)\(\pm\) 2.06 \(\times\) 10\({}^{6}\) \({}^{\rm a}\) & 8.72 \(\times\) 10\({}^{7}\)\(\pm\) 9.48 \(\times\) 10\({}^{6}\) \({}^{\rm a}\) & 2.62 \(\times\) 10\({}^{7}\)\(\pm\) 1.22 \(\times\) 10\({}^{7}\)\({}^{\rm c}\) & 4.81 \(\times\) 10\({}^{7}\)\(\pm\) 4.45 \(\times\) 10\({}^{6}\) \({}^{\rm b}\) \\ \hline Yeast count (Count/mL) & 4.33 \(\times\) 10\({}^{7}\)\(\pm\) 2.66 \(\times\) 10\({}^{5}\) \({}^{\rm a}\) & 2.55 \(\times\) 10\({}^{7}\)\(\pm\) 1.71 \(\times\) 10\({}^{6}\) \({}^{\rm b}\) \({}^{\rm c}\) & 1.93 \(\times\) 10\({}^{7}\)\(\pm\) 1.02 \(\times\) 10\({}^{7}\)\({}^{\rm c}\) & 3.88 \(\times\)Figure 3: Flow cytometer particle counts for the forward scatter (FSC) and the sideward scatter (SSC) of four fermentations with different pretreated word: CW, control word; FW, filtered word; BW, boiled word; and AW, autoclaved word. Black boxes display the area that was considered for the yeast cell count and viability. Darker colours indicate a higher count in the area of the graph. Figure 2: Ankom gas production curve over 68 h for four pretreated words inoculated with the same yeast. Figure 4: Spider diagram of the QDA mean panel scores for spirits of four pretreatment conditions for wort. Figure 5: MFA plot of the QDA data, resulting from 12 panellists, for spirits of four pretreatment conditions for wort MFA analysis, for each panellist first. The compositional analysis of congeners by GC-MS (Figure 6) shows that, overall, the concentration of the most detected esters, higher alcohols, carbonyl compounds, acetals, and others were reduced compared to the control word. However, the levels of acids and sulphides increased compared to the control word. By selecting the congeners that predominantly impact the separation between groups (Figures 6 and 7), the filtered word had lower peak areas for esters and higher alcohols, while the peak areas for the acids and curtained congeners of each group were increased. The few esters that increased belonged to the group of fatty acid ethyl esters. The decrease in esters and higher alcohols was an unexpected result because the presence of lactic acid bacteria in whisky is often connected to higher acid and ester concentrations [23; 49; 50; 2; 3; 4; 7; 18; 23; 49; 2]. Nevertheless, less turbid words are linked to a reduction in fatty acids [51], which are needed for ester production and explains their low concentration. Figure 6: Heatmap of selected congener that drove the separation between the pretreatment techniques. While higher acid concentrations were detected in the filtered word, and the pH was significantly lower than the control word, the filtered word had the lowest peak areas for most esters.