## 2 Results  
### Oenological Parameters  
In order to assess the enological parameters of apple wines maturered in the presence of chips of various tree species and in oak barrels, the total acidity, alcohol content and extract content were analysed. The results are presented in Table 1.  
The total acidity of wines aged in the presence of wood chips ranged from 7.64 to 7.71 g of malic acid per litre, with all cases exhibiting significantly lower values than those observed in control apple wine aged for one year in an oak barrel (7.75 g of malic acid/L). It should be highlighted that the results were consistent and the acidity of the wines was not dependent on the type of wood used. In the case of additions of heavily toasted oak wood chips, a lower acidity value was observed than in the case of lightly- and medium-toasted oak chips. Conversely, heavily toasted apple wood chips increased the acidity of apple wines. However, both of these differences were not statistically significant.  
Two key parameters of wines are alcohol content and extract content. The alcohol content of all wines aged in contact with wood chips was found to be consistently homogeneous, with values ranging from 11.52 to 11.57% (Table 1). It was demonstrated that neither the type of wood from which the chips were made nor the level of toasting had any effect on the alcohol concentration in apple wines. It is of significant importance to note that the  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Parameters**} & \multicolumn{4}{c}{**Toasting Level**} \\ \cline{2-5}  & **Lightly** & **Medium** & **Heavily** & \\  & **Toasted** & **Toasted** & **Toasted** & **Barrel** \\ \cline{2-5}  & & **1 Month** & & **1 Year** \\ \hline Total acidity & & & & \\
[g of malic acid/L] & & & & \\ Oak & 7.66 \(\pm\) 0.14 \({}^{\text{a}}\) & 7.68 \(\pm\) 0.10 \({}^{\text{a}}\) & 7.64 \(\pm\) 0.00 \({}^{\text{a}}\) & 7.75 \(\pm\) 0.01 \({}^{\text{b}}\) \\ Maple & 7.68 \(\pm\) 0.04 \({}^{\text{a}}\) & 7.68 \(\pm\) 0.04 \({}^{\text{a}}\) & 7.68 \(\pm\) 0.08 \({}^{\text{a}}\) & — \\ Apple & 7.68 \(\pm\) 0.10 \({}^{\text{a}}\) & 7.68 \(\pm\) 0.04 \({}^{\text{a}}\) & 7.71 \(\pm\) 0.00 \({}^{\text{a}}\) & — \\ Cherry & 7.68 \(\pm\) 0.10 \({}^{\text{a}}\) & 7.68 \(\pm\) 0.08 \({}^{\text{a}}\) & 7.68 \(\pm\) 0.04 \({}^{\text{a}}\) & — \\ \hline Alcohol content [\% /v] & & & & \\ Oak & 11.52 \(\pm\) 0.01 \({}^{\text{a}}\) & 11.56 \(\pm\) 0.01 \({}^{\text{a}}\) & 11.52 \(\pm\) 0.01 \({}^{\text{a}}\) & 11.21 \(\pm\) 0.03 \({}^{\text{b}}\) \\ Maple & 11.53 \(\pm\) 0.01 \({}^{\text{a}}\) & 11.54 \(\pm\) 0.03 \({}^{\text{a}}\) & 11.57 \(\pm\) 0.02 \({}^{\text{a}}\) & — \\ Apple & 11.52 \(\pm\) 0.09 \({}^{\text{a}}\) & 11.56 \(\pm\) 0.02 \({}^{\text{a}}\) & 11.55 \(\pm\) 0.05 \({}^{\text{a}}\) & — \\ Cherry & 11.56 \(\pm\) 0.01 \({}^{\text{a}}\) & 11.56 \(\pm\) 0.02 \({}^{\text{a}}\) & 11.56 \(\pm\) 0.02 \({}^{\text{a}}\) & — \\ \hline Extract content [\({}^{\text{a}}\)Blg] & & & & \\ Oak & 2.98 \(\pm\) 0.01 \({}^{\text{a}}\) & 2.98 \(\pm\) 0.01 \({}^{\text{a}}\) & 2.99 \(\pm\) 0.01 \({}^{\text{a}}\) & 3.15 \(\pm\) 0.02 \({}^{\text{b}}\) \\ Maple & 2.98 \(\pm\) 0.00 \({}^{\text{a}}\) & 2.99 \(\pm\) 0.01 \({}^{\text{a}}\) & 2.97 \(\pm\) 0.02 \({}^{\text{a}}\) & — \\ Apple & 2.97 \(\pm\) 0.00 \({}^{\text{a}}\) & 2.97 \(\pm\) 0.02 \({}^{\text{a}}\) & 2.97 \(\pm\) 0.01 \({}^{\text{a}}\) & — \\alcohol content of wines that had been aged in oak barrels for one year was found to be statistically significantly lower, reaching 11.21%.  
The content of total extract in apple wines matured in the presence of chips of various tree species was found to be equal, with no statistically significant differences (Table 1). Similarly to the alcohol content, there was no significant influence of the degree of toasting of the wood chips on the level of wine extract. However, the ageing of the wines in oak barrels contributed to a significant (over 5%) increase in the extract content.