## 1 Introduction
Several factors influence the volatile composition of grape marc spirits, including grape varietal origin, pomace storage method, fermentation duration, distillation technology, and the quality and length of the wooden barrels used in the aging process [13; 14]. According to Regulation (EC) 787/2019, a grape marc spirit is required to have an ethanol content of at least 15% (\(v/v\)) [15; 16]. Tsipouro, except for ethanol and water, is composed of hundreds of volatile and semi-volatile compounds derived from grape marc seeds and peels, or created during pomace fermentation [17]. These metabolites are responsible for organoleptic characteristics which determine the quality of the spirits. Furthermore, they are utilized as markers of grape variety and maturation state at harvest, geographical origin, grape pomace storage conditions, and/or distillation technique applied [18; 19]. Aroma is a key factor in determining the organoleptic quality and style of a given distillate. Higher alcohols, acids, ethyl and acetate esters, aldehydes, and terpen are the main group of compounds detected in alcoholic beverages. 2-Methylpropan-1-ol, amyl alcohols, 2-phenylethylanol, acetic acid, acetaldehyde, ethyl acetate, ethyl lactate, 1-hexanol, linalool,and _alpha_-terpineol are the major compounds responsible for the aroma of spirits such as tispouro [1; 7; 9; 15; 20; 21; 22]. Several extraction techniques, analytical methods, and detectors have been applied by researchers for the study of the volatile composition of various grape marc spirits. Gas chromatography coupled with a flame ionization detector (GC-FID) [23; 24; 25; 26; 27; 28] and gas chromatography coupled with mass spectrometry (GC-MS) with direct injection of the sample [29], commonly following an extraction procedure [10; 18; 30; 31; 32], have been previously used for the determination of volatile profile of European distillates. Only a few of these methods have been applied to study the volatilome of Greek tispouro and tiskoudia; nevertheless, Nuclear Magnetic Resonance (NMR) spectroscopy approaches have been used to monitor the metabolic profile of Greek distillates [6; 9; 33]. Headspace Solid Phase Microextraction (HS-SPME) is a cutting-edge approach for analyzing aroma and volatile compounds because it is a simple, effective, and less expensive extraction process that requires limited solvent manipulation, and it is easily automated if a specific SPME autosampler is provided [7; 34]. SPME is the most commonly used sample preparation procedure for the detection of volatile and semi-volatile metabolites in distillate samples. The main HS-SPME parameters, which affect the detection of several volatile compounds in distillates, are the type of SPME fiber, the extraction time and temperature, the desorption time and temperature, the sample volume, and the concentration of salt. SPME settings commonly entail the use of mixed-sorbent fibers and HS extraction at temperatures ranging from 25 to 55 \({}^{\circ}\)C for 15-60 min [13; 35; 36; 37]. To the best of the authors' knowledge, whilst aroma is a quality attribute for alcoholic beverages, only one study previously applied an HS-SPME-GC-MS method to analyze Greek tispouro [21]. This study aimed to determine the volatile metabolic fingerprint of Greek distillates tispouro and tiskoudia in order to complete the lack of literature about the analysis of their volatilome using modern techniques. The aroma profile of tispouro of different regions in Greece, produced by several native grape cultivars, was herein outlined for the first time.