## 3 Results and Discussion  
### Physicochemical Analysis  
Table 1 summarises the results of the basic analytical determinations over the ageing time. The ANOVA results for acidity (Table 1) of the AUS reveal that the control spirit had significantly lower values compared to the aged ones. Additionally, the AUSs aged for 6 months presented significantly higher values than the spirits aged for 3 months. Concerning the toasting level, a trend to higher values of acidity in the spirits aged with medium toast level was observed. The increase of acidity with ageing time and with toasting level intensity is also reported for other spirits [33; 34; 35]. pH values of a spirit drink usually vary with the ageing time, however, for these samples they were not significantly different over time. This result can be explained by the short ageing time set (three and six months), compared to what is normally used for other spirit drinks. The values of total acidity and pH (0.17-0.59 and 3.50-4.01, respectively) are within the range of values found in AUS in previous works [6; 12; 36]. The dry extract increased with the ageing time, but more significantly with the toasting level (Table 1), which is ascribed to the extent of changes caused by the toasting level on the chemical composition and on the structure of the wood. Results show that MT promoted more favourable conditions than LT, giving rise to higher extraction of compounds from the wood to the distillate, positively influencing the dry extract in both sampling times. However, MPT seemed to cause an imbalance between compound formation and degradation under the influence of a more intense toasting, resulting in lower dry extract in the \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Samples**} & \multirow{2}{*}{**Total acidity**} & \multirow{2}{*}{**Fixed acidity**} & \multirow{2}{*}{**Volatile acidity**} & \multirow{2}{*}{**pH**} & \multirow{2}{*}{**Dry Extract** (mg/L)} \\ \cline{2-2} \cline{5-6}  & & & & & & \\ \hline C & 0.140 \(\pm\) 0.00 \({}^{*}\) & 0.009 \(\pm\) 0.001 \({}^{*}\) & 0.130 \(\pm\) 0.001 \({}^{*}\) & 3.91 \(\pm\) 0.02 & 10 \(\pm\) 2.00 \({}^{*}\) \\ LT3 & 0.198 \(\pm\) 0.003 a & 0.063 \(\pm\) 0.010 & 0.135 \(\pm\) 0.024 a & 4.01 \(\pm\) 0.09 & 435 \(\pm\) 657.2 a \\ MT3 & 0.210 \(\pm\) 0.036 a & 0.075 \(\pm\) 0.013 a & 0.135 \(\pm\) 0.044 a & 3.86 \(\pm\) 0.01 a & 740 \(\pm\) 245.4 d \\ MT3 & 0.298 \(\pm\) 0.025 b & 0.070 \(\pm\) 0.014 b & 0.228 \(\pm\) 0.029 b & 3.91 \(\pm\) 0.022 a & 626 \(\pm\) 118.6 c \\ LT6 & 0.265 \(\pm\) 0.042 b & 0.078 \(\pm\) 0.005 a & 0.188 \(\pm\) 0.039 a & 3.77 \(\pm\) 0.14 a & 534 \(\pm\) 14 b \\ MT6 & 0.330 \(\pm\) 0.024 c & 0.105 \(\pm\) 0.006 c & 0.225 \(\pm\) 0.026 b & 3.85 \(\pm\) 0.03 a & 793 \(\pm\) 538.3 d \\ MP76 & 0.325 \(\pm\) 0.031 c & 0.083 \(\pm\) 0.005 b & 0.243 \(\pm\) 0.030 c & 3.97 \(\pm\) 0.03 a & 678 \(\pm\) 59.1 c \\ \hline \hline \end{tabular} \({}^{*}\)Control denotes significant differences from the ageing modalities. Means within the same column followed by different letters are significantly different (\(p<0.05\)) according to [PERSON]’s test.  
\end{table} 
Table 1: ANOVA results and mean values of acidity, pH, and dry extract of the AUS aged with oak. corresponding AUS samples than those of MT in both sampling times. These results are in accordance with those obtained in the ageing of other spirits, such as wine spirits [33] and plum distillates [27]. The control spirit presented a quit null dry extract denoting a good distillation process. The values shown in Table 2 for alcohol strength were above the minimum required by the European regulation [8] and are within the range of values observed in other studies [6; 12; 36]. Alcohol strength of aged AUS present values ranging between 46.8% and 47.9% and shows an insignificant variation because this essay was made in bottles in which ethanol evaporation did not occur during the ageing process.