## 4 Conclusions  
The proposed protocol was found to be suitable for the identification of 92 volatile compounds in the analyzed distillates, including alcohols, esters, acids, carbonyl compounds, terpenes, terpenoids, and flavored compounds originating from the addition of anise in spirits. PCA and OPLS-DA models were applied for the classification of the majority of the samples according to their geographical origin, while biomarker assessment revealed the statistically significant metabolites of this discrimination. An important compound group of the volatilome of Greek grape marc spirits is the group of terpenoids. Linalool, geraniol, and nerol oxide were more abundant in Thessaloniki, Limnos, and Thessaly samples produced from Muscat and Muscat of Alexandria pomaces; _alpha_-terpineol and terpinen-4-ol were detected in higher concentrations in Macedonia, Thessaloniki, and Thessaly samples (also produced from Muscat pomaces). All of these samples were aniseed distillates. Tsipouro samples from Macedonia presented high concentrations of monoterpenes, i.e., over 50-fold higher than the other samples in most cases. Limnos samples were found to be richer in hotrienol, anethol, and other flavored compounds. Other compounds, such as fenchone and carvone, were found to be higher in Thessaly and Macedonia samples, while _gamma_-isogenaiol, _trans_-_p-mentha-1(7),8-dien-2-ol, and thymyl ethyl ether were very abundant in Thessaly samples. Regarding the other groups of detected compounds, tsipouro samples from Thessaly presented very high concentrations of fatty acids. Samples from Macedonia were found to be richer in ethyl octanoate, while Thessaloniki, Thessaly, and Pella samples were richer in ethyl decanoate and ethyl dodecanoate; ethyl palmitate was higher in the Limnos and Thessaloniki samples. Most of the higher alcohols were observed in higher concentrations in grape marc spirit from Cyprus, followed by Limnos, Macedonia, and Thessaly samples; 2-methylpropan-1-ol, was more abundant in Crete, Thessaloniki, and Pella distillates. The results of this study may be a tool for producers in Greece to make high-quality grape marc spirits based on the special aroma characteristics of each production area. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/beverages9030065/s1](https://www.mdpi.com/article/10.3390/beverages9030065/s1)]([https://www.mdpi.com/article/10.3390/beverages9030065/s1](https://www.mdpi.com/article/10.3390/beverages9030065/s1)), Table S1. Sample number, region, grape variety and addition of aromatic material of the analyzed samples. Table S2. Compound name, retention time (RT), chemical formula, molecular weight (MR) and relative concentration (mg L\({}^{-1}\)) according to the production region of the metabolites identified in analyzed Greek distillates; Table S3. VIP, p(corr) and _p_-values of the statistically significant volatile metabolites of the discrimination between Crete-Soultanina and Macedonia Greek grape marc spirits; Table S4. VIP, p(corr) and _p_-values of the statistically significant volatile metabolites of the discrimination between Crete and Limnos Greek grape marc spirits; Table S5. VIP, p(corr) and _p_-values of the statistically significant volatile metabolites of the discrimination between Macedonia and Limnos Greek grape marc spirits; Table S6. VIP, p(corr) and _p_-values of the statistically significant volatile metabolites of the discrimination between Crete and Thessaloniki Greek grape marc spirits; Table S7. VIP, p(corr) and _p_-values of the statistically significant volatile metabolites of the discrimination between Thessaloniki and Pella Greek grape marc spirits. Figure S1. Boxplots of representative esters among Greek grape marc spirit samples. Black dots represent the samples and yellow dots are the mean values; Figure S2. Boxplots of representative acids, alcohols and carbonyl compounds among Greek grape marc spirits. Black dots represent the samples and yellow dots are the mean values; Figure S3.