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Terraced vineyards are cultural landscapes with a special value. The increase in costs and the lack of professional workers make viticulture on terraces difficult to be maintained. Thus, in the face of climate change and production challenges, we aimed to study the impact of slope-wise cultivation on wine quality. The quality of Merlot wines from terraced and slightly lower non-terraced vineyards within a small area characterised by similar mesoclimatic features was compared in the seasons 2019 and 2020. The non-terraced and terraced vineyards differed in both soil profile and morphology. The number of buds, number of clusters, and leaf area were standardised, and the stem water potential (SWP) was measured during wine-growing seasons. Upon reaching maturity, grapes were hand-picked on the same day in all vineyards and microvinified. The wines were analysed chemically and sensorially. In both years, the SWP showed higher water stress in the vines from terraces. The yield, berry weight, and leaf area were lower on terraced than on non-terraced vineyards in both years, and the skin- and seed-to-flesh ratios were higher. The darker seed colour pointed to the advanced ripening on terraces, where the wines had a higher alcohol concentration and a higher total dry extract. The wines from terraces had higher concentrations of total polyphenols, anthocyanins, and proanthocyanidins (PAs) than the wines from non-terraced vineyards in both years, and the PAs in the wines from terraces in 2019 had fewer prodelphinidins and were more galloylated. Higher concentrations of higher alcohols and lower concentrations of esters and methoxypyrazines were found in the wines from terraces. The sensory analysis revealed a preference for wines from terraces with better colour intensity, fruitiness, astringency, midpalate, and overall quality. Under experimental conditions (the same harvest date, standardised viticultural variables), the wines from terraces had both better phenolic potential and better sensory quality than the wines from non-terraced vineyards.

The pressure chamber is the most used tool for plant water status monitoring. However, species/cultivar and seasonal effects on protocols for reliable water potential determination have not been properly tested. In four grapevine cultivars and two times of the season (early season, Es; late season, Ls, under moderate drought), we assessed the maximum sample storage time before leaf water potential (Ψleaf) measurements and the minimum equilibration time for stem water potential (Ψstem) determination, taking 24 h leaf cover as control. In ‘Pinot gris’, Ψleaf already decreased after 1 h leaf storage in both campaigns, dropping by 0.4/0.5 MPa after 3 h, while in ‘Refosk’, it decreased by 0.1 MPa after 1 and 2 h in Es and Ls, respectively. In ‘Merlot’ and ‘Merlot Kanthus’, even 3 h storage did not affect Ψleaf. In Es, the minimum Ψstem equilibration was 1 h for ‘Refošk’ and 10 min for ‘Pinot gris’ and ‘Merlot’. In Ls, ‘Merlot Kanthus’ required more than 2 h equilibration, while 1 h to 10 min was sufficient for the other cultivars. The observed cultivar and seasonal differences indicate that the proposed tests should be routinely performed prior to experiments to define ad hoc procedures for water status determination.

The efficient extraction of phenols from grapes is an important step for their reliable quantification. The aim was to optimise the lyophilisation process and the extraction of phenols from grape skins and seeds. The phenol extraction yield from lyophilised tissues was investigated with different accelerated solvent extraction (ASE) operating conditions. Skins and seeds were separated from frozen berries and lyophilised without being ground. The weight loss during lyophilisation was followed daily. Phenols were extracted from lyophilised, cryo-ground seeds and skins with ASE at room temperature and 10.3 MPa using 80% aqueous acetone and 60% aqueous methanol. The effects of ASE operational parameters (the number of extraction cycles (ECs) and static time (ST) duration) were investigated. The yield of extracted phenols was evaluated spectrophotometrically by determining total phenolic index at 280 nm (TPI). The weight of skins and seeds significantly dropped after 24 h of lyophilisation and continued to decrease, although not significantly, up until the 9th day. The optimal lyophilisation time was estimated to be 3 days and 5 days for skins and seeds, respectively. The phenol extraction yield was significantly affected after changes of ASE conditions. Based on TPI, the optimal ASE conditions were as follows: (i) lyophilised seeds—eight ECs with 10 min ST using aqueous acetone and then four ECs with 20 min ST using aqueous methanol; (ii) lyophilised skins—eight ECs with 1 min ST using aqueous acetone and then one EC with 20 min ST using aqueous methanol.