## 3 Results and Discussion
### Chemical and Colour Properties  
The effect of underwater aging on the chemical parameters of the liquew, including total acidity, volatile acidity, ethanol content, and pH, was assessed by analysing two composite samples. These two bulk samples were made by equally mixing the individual bottles from both the cellar-aged (C) and underwater-aged (S) groups. The results are presented in Table 3.  
Although no significant differences were observed, a trend towards a higher ethanol content was noted in the underwater-aged sample, suggesting a reduced oxidation process during the one-year aging period. The results are in agreement with recent preliminary studies on bottle-aged wines stored underwater and in cellars, although these studies investigated a shorter aging period compared to the present study [16; 18].  
The CIELab colour analysis revealed no statistically significant differences in the L* (lightness) or a* (red-green) values between the S and C samples (Table 3).  
However, the b* (yellow-blue) value was significantly higher in the C samples compared to the S samples, suggesting an intensification of yellow tones during cellar aging. The calculated \(\Delta E\) value, which represents the colour difference between C and S samples, was 1.90. This value indicates minimal overall colour differences between the two aging methods. While this difference is below the threshold typically perceptible to an untrained observer, it may be noticeable to a trained assessor.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multicolumn{5}{c}{**Confusion Matrix for the Training Samples**} \\ \hline from\textbackslash{}to & Cellar & Sea & Total & \% correct response \\ \hline Cellar & 34 & 0 & 34 & 100\% \\ Sea & 2 & 32 & 34 & 94\% \\ \hline Total & 36 & 32 & 68 & 97\% \\ \hline \multicolumn{5}{c}{**Confusion Matrix for the Cross-Validation Results**} \\ \hline from\textbackslash{}to & Cellar & Sea & Total & \% correct response \\ \hline Cellar & 33 & 1 & 34 & 97\% \\ Sea & 2 & 32 & 34 & 94\% \\ \hline Total & 35 & 33 & 68 & 96\% \\ \hline \hline \end{tabular}
\end{table}
Table 2: Confusion matrix from discriminant analysis of E-nose data, showing correct and incorrect classifications for 34 cellar-aged (C) and 34 underwater-aged (S) liquor samples in both training and cross-validation.  
\begin{table}
\begin{tabular}{c c c} \hline \hline  & **S** & **C** \\ \hline Ethanol (\% \(v/v\)) & 26.27 \(\pm\) 0.12 a & 26.10 \(\pm\) 0.10 a \\ Total acidity (g/L) & 3.23 \(\pm\) 0.14 a & 3.21 \(\pm\) 0.15 a \\ Volatile acidity (g/L) & 0.21 \(\pm\) 0.01 a & 0.215 \(\pm\) 0.01 a \\ pH & 3.66 \(\pm\) 0.01 a & 3.66 \(\pm\) 0.02 a \\ \hline L* & 26.16 \(\pm\) 0.15 a & 25.57 \(\pm\) 0.74 a \\ a* & \(-\)2.61 \(\pm\) 0.51 a & \(-\)3.51 \(\pm\) 1.52 a \\ b* & 4.59 \(\pm\) 0.59 b & 5.97 \(\pm\) 1.19 a \\ \hline \hline \end{tabular} Values are reported as mean \(\pm\) standard deviation. Different letters indicate statistically significant differences (\(p\leq 0.05\)). Total acidity is expressed as g/L of tartaric acid, while volatile acidity is expressed as g/L of acetic acid. L*, a*, and b* represent the colour values in the CIELab scale.  
\end{table}
Table 3: Ethanol content, total acidity, volatile acidity, pH and instrumental colour parameters of liquor samples aged underwater (S) and in the cellar (C) for 12 months.