# Pairing Red Wine and Closure: New Achievements from Short-to-Medium Storage Time Assays
## 3 Results and Discussion
### Determination of the Oxygen Transfer Rate
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multicolumn{2}{c}{**Douro Red Wine**} & \multicolumn{2}{c}{**Burgenland Red Wine**} \\ \cline{2-7}  & **Natural Cork 1** & **Micro A** & **Natural Cork 2** & **Micro A** & **Micro E** & **Screw Cap** \\ \hline Total acidity (g/L & & & & & \\ tartaric acid) & 5.60 \(\pm\) 0.06 \({}^{\text{a}}\) & 5.55 \(\pm\) 0.06 \({}^{\text{a}}\) & 4.766 \(\pm\) 0.06 \({}^{\text{a}}\) & 4.779 \(\pm\) 0.06 \({}^{\text{a}}\) & 4.805 \(\pm\) 0.06 \({}^{\text{a}}\) & 4.751 \(\pm\) 0.06 \({}^{\text{a}}\) \\ Volatile acidity & & & & & \\ SO\({}_{2}\) (g/L acetic acid) & 0.76 \(\pm\) 0.05 \({}^{\text{a}}\) & 0.76 \(\pm\) 0.05 \({}^{\text{a}}\) & 0.717 \(\pm\) 0.05 \({}^{\text{a}}\) & 0.711 \(\pm\) 0.05 \({}^{\text{a}}\) & 0.714 \(\pm\) 0.05 \({}^{\text{a}}\) & 0.684 \(\pm\) 0.05 \({}^{\text{a}}\) \\ SO\({}_{2}\) free (mg SO\({}_{2}\)/L) & 22 \(\pm\) 6 \({}^{\text{a}}\) & 19 \(\pm\) 6 \({}^{\text{a}}\) & 28 \(\pm\) 6 \({}^{\text{a}}\) & 30 \(\pm\) 6 \({}^{\text{a}}\) & 29 \(\pm\) 6 \({}^{\text{a}}\) & 26 \(\pm\) 6 \({}^{\text{a}}\) \\ SO\({}_{2}\) total (mg SO\({}_{2}\)/L) & 56 \(\pm\) 8 \({}^{\text{a}}\) & 53 \(\pm\) 8 \({}^{\text{a}}\) & 83 \(\pm\) 8 \({}^{\text{a}}\) & 91 \(\pm\) 8 \({}^{\text{a}}\) & 85 \(\pm\) 8 \({}^{\text{a}}\) & 77 \(\pm\) 8 \({}^{\text{a}}\) \\ pH & 3.76 \(\pm\) 0.04 \({}^{\text{a}}\) & 3.79 \(\pm\) 0.02 \({}^{\text{a}}\) & 3.70 \(\pm\) 0.01 \({}^{\text{a}}\) & 3.70 \(\pm\) 0.02 \({}^{\text{a}}\) & 3.70 \(\pm\) 0.01 \({}^{\text{a}}\) & 3.69 \(\pm\) 0.01 \({}^{\text{a}}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Physicochemical parameters (total acidity, volatile acidity, volatile acidity deduced from SO\({}_{2}\), SO\({}_{2}\) free, SO\({}_{2}\) total, and pH) of the Douro and Burgenland red wines stored for 35 and 5 months, respectively. The results are expressed as the averages of 4 bottles \(\times\) 3 replicates (n = 12) \(\pm\) the standard deviation. able level of dispersion in the responses obtained by this panel, retronasal perception is still possible to observe statistically significant differences between the 2 wines (\(p<0.05\)), where wines bottled with Natural Cork 1 exhibited a slightly higher level of oxidation (0.60 \(\pm\) 0.50) than those sealed with micro-agglomerated Micro A (\(-\)0.40 \(\pm\) \(-\)1.00). For the Burgenland wines stored for 5 months, a scale from 1 to 4 was used, where 1 represented the most reductive character and 4 the most oxidized character. For orthonasal perception, no statistical differences were observed (\(p>0.05\)) between wines bottled with different closures, as previously described for Douro wines, with longer storage times (35 months). Otherwise, for retronasal perception, no significant differences (\(p>0.05\)) were observed, with the exception of wines sealed with Micro E and a screw cap (\(p<0.05\)). Despite no statistically significant differences being noticed, it is worth highlighting the fact that wines sealed with a screw cap tended to exhibit a more reductive character at a retronasal level. While the OTR data showed no significant differences among the natural and micro-agglomerated cork stoppers under study (Figure 1), Douro red wines sealed with natural cork stopper for a medium-length storage time seemed to present stronger oxidation characteristics only for retronasal perception, which may be due to variability in oxygen ingress (Natural Cork 1 exhibited tendentially higher OTR). The absence of statistically significant differences in the orthonasal perception, for both wines, can be explained by the fact that aroma perception primarily involves simple volatile compounds present at lower concentrations, which are less affected by the type of closure (19; 20). In contrast, the differences observed in the retronasal perception stem from flavor perception being