Search Results (4)

A study was conducted in a winery in Puglia on the effect of cooling crushed and destemmed Bombino Nero grapes, comparing two different systems: (1) traditional indirect heat exchange using a water-cooled with a tube-in-tube heat exchanger and (2) a direct refrigeration system with a CO₂ system. The must obtained from crushed grapes cooled with CO₂, compared to that treated with an exchanger, has a lower ethanol content, greater presence of sugars and higher color and tone; these qualitative advantages are due to much faster cooling and deoxygenation, which slowed down the development of indigenous yeasts present on the surface of the grapes and allowed for greater extraction of the anthocyanin components in the must. These qualitative advantages give added value to the wine, justifying higher energy costs. In fact, the test results highlighted limitations associated with higher energy costs for the direct cooling system with CO₂ compared to the traditional one with indirect heat exchange. Energy consumption in the winery is lower for the CO₂ system, but energy and costs for capture, liquefaction and stockage must also be considered. However, from an energy and functional point of view, the potential advantages related to the clarification phase should not be neglected: it could be carried out at higher temperatures than those currently adopted for musts treated with CO_2, limiting the amount of the required CO₂ and consequently the total energy consumption for the whole process. Full article

Grapevine trunk diseases are a threat to table- and grape-wine cultivation worldwide. Phaeomoniella chlamydospora (Pch) is a vascular fungus recognized as one of the most important pathogens associated with grapevine trunk diseases. The relationships between xylem vessel features and Pch susceptibility of 10 table- and 17 wine-grape genotypes, as well as 3 rootstocks, were investigated by image analysis of 50 µm cross-sections and artificial Pch inoculation on one-year-old vine cuttings. Vessels were grouped in the diameter classes 1–30, 31–60, 61–90, 91–120, and >120 µm. Among the table-grape varieties, ‘Sable’, ‘Timco’, and ‘Red Globe’ showed higher densities of large vessels (>120 μm) than ‘Italia’, ‘Sugar Crisp’, and ‘Sugraone’. Among the wine-grape varieties, ‘Minutolo’, ‘Montepulciano’, ‘Primitivo’ CDTa19, and ‘Verdeca’ showed higher densities of large vessels than ‘Aglianico’, ‘Nero di Troia’, ‘Sangiovese’, and ‘Susumaniello’. In the rootstocks, the vessel diameters were 50.8, 54.0, and 60.9 μm for ‘34 E.M.’, ‘140 Ruggieri’, and ‘1103 Paulsen’, in that order. For table-grape varieties, Pch was re-isolated from 13.3% for ‘Sugar Crisp’ and ‘Sugraone’ cuttings up to 93.3% for ‘Timco’. For wine-grape varieties, Pch re-isolation ranged from 51.1% (‘Bombino nero’, ‘Negroamaro’ D15, and ‘Sangiovese’) to 81.1% (‘Montepulciano’), while for the rootstocks, the values were from 33 to 51%. A principal component analysis (PCA) revealed a positive correlation between the frequencies of large vessels and Pch re-isolation. In addition, in wine grapes and rootstocks, higher Pch re-isolation frequencies in the lateral parts of cuttings were correlated (r = 0.79) to a higher frequency of large vessels. The results highlight relationships between grapevine xylem vessel sizes and susceptibility to P. chlamydospora that are worthy of further research. Full article

Global warming poses a threat to winemaking worldwide, especially in dry–warm regions such as Southern Italy. Must fermentation with non-Saccharomyces yeast starter is a possible approach to limit the negative effects of climate change, leading to desirable effects such as an increase in total acidity and/or aroma improvement. The aim of this study was to evaluate the effects of the use of a non-Saccharomyces starter (Lachancea thermotolerans) on the chemical and sensory properties of wines obtained by the the fermentation of two autochthonous Apulian grape cultivars, namely Bombino nero and Minutolo, as compared to the traditional Saccharomyces cerevisiae-driven fermentation. Bombino and Minutolo wines fermented with either Lachancea thermotolerans or Saccharomyces cerevisiae were characterized for their oenological parameters, volatile profiles, and sensory properties. Both chemical and sensory properties were affected by the yeast starter. Inoculation of L. thermotolerans increased sensory complexity, with different floral and sweet-like attributes for both cultivars. Bombino nero, a neutral cultivar, showed a clear effect on wine composition, with both an increase in lactic acid and a change in the volatile profile. On the contrary, the impact of L. thermotolerans was partially masked in Minutolo due to the strong primary aroma background of this highly terpenic cultivar. In this work, we evidenced a notable cultivar × yeast interaction, showing how generalizations of the effects of non-Saccharomyces yeasts on vinification are difficult to achieve, as they show a cultivar-specific outcome. Full article

In this article, experimental tests on two different kinds of pneumatic presses have been carried out in two Apulian wineries to evaluate energy consumption related to yield performance. The presses are employed to process Bombino Nero variety grapes, crushed and transformed in rosé wine though a pomace less process. The pneumatic pressured press realized a 2 h:48 min long process, with a maximum pressure on the product of 1.4 bar and a must moulding of 69% of extracted must. In regard to the vacuum press, the process duration is 3 h:18 min, with a maximum pressure of 0.9 bar and a must moulding of 58%. During the pressing operation, mean values of must flow rate are comparable: 2.1 L min⁻¹ m⁻² for the pressured press and 2.9 L min⁻¹ m⁻² for the vacuum press. However, a more detailed analysis gives more insight on the behaviour of the two presses. In regard to the pressured press, a compression phase characterized by few steps and at lowest pressure values has proven particularly effective, especially in the first phase (must moulding of 41% with a must flow rate of 4.6 L min⁻¹ m⁻²), at the lowest pressure values. On the other hand, by analysing vacuum press process, the phases sequence is much more gradual, must moulding decreases as the extraction proceeds (from 28% to 6%), and in the last three phases a very low amount of must is extracted, with must moulding smaller than 10%. The energy consumption of the pressured press during compression is mainly related to the engine power absorption (one of the two in operation), and it is below 4 kW except during start-up, due to the starting currents. The highest power is reached in the last phase in which the maximum pressure is applied and a great amount of must is extracted. On the other hand, energy consumption in the vacuum press gradually decreases. A similar trend was not observed for the specific energy for either press: while it increases along the whole process for the vacuum press, it reaches a maximum value in the second phase of the pressured one. Results show the need to pursue new studies on single component design and on pressing cycles, especially in high-capacity pneumatic vacuum presses. Several advantages on wine production costs could be achieved, even retaining high quality wines. Full article