## 2 Materials and Methods
### Extraction of Volatile Compounds  
For the extractions of volatile compounds from sparkling wine after aging in a bottle for 94 months, we used two methodologies. HS-SPME. First, a 5 mL of each sample and 1.25 g of NaCl were placed in a 20 mL vial, capped with a PTFE septum (Supelco, Bellefonte, PA, USA) and analyzed by HS-SPME-GCMSMS. The method is an adaptation from the one described in [23]. The extraction was carried out using a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber (Supelco Inc., Bellefonte, PA, USA) that was inserted into the headspace (HS). The extraction conditions were 40 \({}^{\circ}\)C for 40 min at 250 rpm. Then, the fiber was desorbed into the injector at 250 \({}^{\circ}\)C for 5 min [43]. Thermal desorption (TD). In TD, the desorption process was carried out in two stages. * First, the desorption tube filled with extracted compounds was heated inside the desorption unit at a certain temperature and for a certain time in order to desorb the analytes adsorbed during tube filling and focus them into a cold trap (or desorption trap). Helium gas was the carrier gas used in split-less mode [42]. Stainless-steel thermal desorption tubes (6 mm O.D. \(\times\) 90 mm long, 5 mm I.D., Markes International Limited, Pontyclun, UK) were used in this study. Tubes were packed with 200 mg of Tenax(r) TA supplied by Ingenieria Analitica, S.L (Barcelona, Spain), a porous polymer resin based on 2,6-diphenylene oxide with a particle size of 20-35 mesh, which was designed for trapping volatile and semi-volatile organic compounds from air [43]. * Then, the desorption trap was heated to a chosen temperature at the maximum heating rate to introduce the retained analytes into the chromatographic column. * The desorption tubes filled with extracted compounds were obtained following a procedure developed in this study. The designed system is shown in Figure 1. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Type** & **Code** & **Closure Description** \\ \hline Cork stopper & Cork 1 & Agglomerated cork stopper with 31 mm of diameter \\ Cork stopper & Cork 2 & Agglomerated cork stopper with 32 mm of diameter \\ Screw cap & CC1 & Polyethylene screw cap consists of a cell polyethylene foam disc \\  & & with a very fine structure. \\ Screw cap & CC2 & Saranex is composed of PE covered on both sides with PVDC \\ Screw cap & CC3 & Daraforim is a non- polyvinylidene (PVC) compound based on \\  & & polyolefinic raw materials \\  & & Saranex + and additive is composed of PE covered on both sides \\ Screw cap & CC4 & with PVDC and with the addition of an additional glue such as \\  & & Varnishe (Araldite) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Closures used for second fermentation and aging of sparkling wine: types, codes and description. \begin{table}
\begin{tabular}{l l l l} \hline \hline  & \multicolumn{3}{c}{**Base Wine**} \\ \hline Total acidity by sulfuric (g L\({}^{-1}\)) & 4.05 & Density (g cm\({}^{3}\)) & 998.9 \\ Sugar (GAP) (g L\({}^{-1}\)) & 23.1 & Turbidity (NTU) & 35.9 \\ NFA (mg L\({}^{-1}\)) & 63.0 & Free SO\({}_{2}\) (mg L\({}^{-1}\)) & 7 \\ Free SO\({}_{2}\) (mg L\({}^{-1}\)) & 8.0 & Temperature (\({}^{\circ}\)C) & 17 \\ Sucrose & 21.3 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Oenological parameters of base wine before the addition of a “tirage solution”. Figure 1 represents a hermetically sealed glass container with an outer coating through which distilled water at 52 \({}^{\circ}\)C flows. Inside the container, 30 mL of sample was heated for 6 min to achieve a constant temperature of 35 \({}^{\circ}\)C. Then, the first desorption tube was inserted to establish contact with the headspace created, and also, it was connected to a suction pump operating at 140 mL min\({}^{-1}\), as shown in Figure 1. The adsorption tube was connected for 5 min, and then it was immediately closed to avoid the loss of retained compounds. Thereafter, another desorption tube was inserted in the same way.