## 1 Introduction  
Greece has a long history of vineyard exploitation and is one of the world's top 20 wine-producing countries. Aside from winemaking, the production of Greek grape marc spirits is an important chapter in the Hellenic vine cultivation history [1, 2]. \"Tispouro\" is the most well-known traditional alcoholic grape marc distillate produced in Greece from winemaking residue (it is known as \"tsikoudia\" or \"raki\" on the island of Crete). Accordingto [PERSON], [PERSON], and [PERSON], distillation in Greece has a long history and dates back to antiquity. Tsipouro and tiskoudia distillates are the outcomes of this tradition [1]. \"Tisipouro\" belongs to the \"grape marc spirit\" category and meets the relevant requirements set out in point 6 of Annex II to Regulation (EC) No 110/2008 [3] and the general requirements for \"Tisipouro\"/\"Tsikoudia\" as displayed in the technical documentation issued by the Directorate of Alcohol & Foodstuffs of the General Chemical State Laboratory of Greece [4]. \"Tisipouro\" is a transparent and colorless liquid with intensive organoleptic characteristics derived from the raw materials used (grape marc and perhaps sediment) and the specific methods of production (distillation means and processes). Its content in volatiles is equal to, or exceeding, 140 g per hectoliter of pure alcohol, while methanol does not exceed 1000 g per hectoliter of pure alcohol. The minimum alcohol by volume is 37.5% vol., and the addition of alcohol is not permitted. The production process of these grape marc distillates includes the selection of the appropriate grape variety, thorough fermentation, and finally the slow and gradual distillation of the fermented grape marc [5; 6]. Anise, fennel, saffron, and walnut tree leaves are a few aromatic seeds or plants that some viticulturists prefer to add. These spirits have recently been recognized as products of protected geographical designations when produced by professional distillers in accordance with European and national law in specific viticultural regions (Annex III, Regulation [EC] No. 110/2008) [3; 7; 8; 9]. Similar distillates with equivalent appellations are produced in numerous countries, particularly around the Mediterranean Sea, including \"zivania\" in Cyprus, \"grappa\" in Italy, \"aguardente\" or \"orujos\" in Spain, and \"bagaceira\" in Portugal. They are also produced in central Europe, specifically \"eau-de-vie de marc\" in France, as well as in some other nations, such as \"rakija\" in Slavic nations and \"tshiatisha\" in Georgia [8; 10]. Tisipouro is a well-known distillate in Greece, and includes different Protected Geographical Indications, such as \"Tispouro of Macedonia\", \"Tisipouro of Thessaly\", and \"Tsikoudia of Crete\". Traditionally, in Northern Greece (Macedonia, Thessaly, Tyrnavos, North Aegean Islands) Tsipouro is often anise-flavored, while this practice is far less common in the South of the country. In Crete, grape marc spirits are called \"Tsikoudia\" and can also derived from raisin (Soultaninan) [3; 11]. The most common grape cultivars employed in the production of Tsipouro in Greece belong to the aromatic family of Muscat (e.g., Muscat in Macedonia and Thessaly, Muscat of Alexandria in Limnos), although other autochthonous or international cultivars are also used. Each region produces a grape marc spirit according to the tradition, the culinary heritage, the cultivated grapes, and the herds grown in the region. According to the General Chemical State Laboratory of Greece, in 2021, tispouro exports reached an equivalent of 110 thousand liters of pure alcohol (Ipa), showing a 37.5% increase in comparison to the previous year, and nearly a four-fold increase compared to 2012 abroad shipments [12]. Therefore, it is important to study the products of each region with a holistic approach in order to characterize the volatilome of tispouro of different regions in Greece.