## 3 Results
### Changes of Aroma Compounds
Except that, the compounds in cluster 1, cluster 3, and cluster 5 were slightly reduced  
Figure 2: \(K\)-means clustering analysis based on the normalized concentrations (left) and the corresponding aroma compounds in each cluster (right) in Riesling wines. “R0” represents before bottling, and “R6” and “R12” individually represent bottle storage for 6 months and 12 months; “T0” represents the control without any cold treatment, and “T10 to T15” individually represent cold treatment for 10 to 15 days. The vertical coordinate was the best value for each center point of the cluster calculated by the \(k\)-means algorithm. only in the wines (R0) with 11-day (and 12-day) cold treatment, and the concentrations of compounds in cluster 4 were not changed by cold treatment (Figure 2). As shown in Table S1, during bottle storage, the concentrations of the compounds in cluster 1 decreased significantly in all wines after 6 months of bottle storage, but no significant difference was found between 6-month and 12-month bottle-storage wines. Among them, linalool and isoamyl acetate were the main terpenoid and acetate ester in the Riesling white wines, respectively. It was also noticed that the concentrations of the compounds in cluster 4 (such as 1,1,6-Trimethyl-1,2-dihydronaphthalene (TDN), furfural, etc.) significantly increased after 12 months of bottling storage. As for the concentrations of the compounds in cluster 3 and cluster 5, the change with the bottle-storage duration differed between the control group and cold treatment groups. The concentrations of cluster 3 compounds in the T0 group decreased significantly after bottle storage, while almost no significant difference was observed in the T10-T15 groups. Cluster 5 included the main component of acetates (ethyl acetate), fatty acid ethyl esters (ethyl lactate), and higher alcohols (isopentanol). Compared with the wine before storage, the concentrations of aroma compounds in the T0 groups did not change significantly during the subsequent bottle storage, while those of the T10-T15 groups increased after 12-month bottle storage. Interestingly, compared with the control group, we observed that most compounds did not change significantly because of the cold treatments at 0 months and 6 months after bottle storage, while some compounds in cluster 1 (1-heptanol, isoamyl acetate, linalool, and methyl octanoate), some of cluster 4 (1-butanol and acetic acid), most of the cluster 3 compounds (such as \(\beta\)-damascenone, \(\beta\)-ionone, ethyl hexanoate, ethyl octanoate, etc. ), all the cluster 5 compounds (such as isopentanol, ethyl lactate, ethyl acetate, ethyl butanoate, etc.) showed significantly higher concentrations in the T10-T15 groups after 12 months of bottle storage. These compounds mainly belonged to ethyl esters, higher alcohols, norisoprenoids, and terpenoids. As for cluster 4, only some treatment groups significantly changed the concentrations of some compounds during the bottle storage duration; for example, the concentrations of TDN in the T14 and T15 groups increased at the end of treatment (R0), and increased in the T12-T15 groups at 6 months of bottle storage (R6), but these differences disappeared at 12 months of bottle storage. The interaction of cold stabilization duration and bottle-storage duration significantly influenced the concentrations of most compounds in the wines, except two compounds in cluster 1 (3-methylpentanol and isopentanoic acid), \(\beta\)-ionone in cluster 3, and three compounds (ethyl 3-methylbutanoate, TDN, and furfural) in cluster 4.