The Content of Selected Bioactive Compounds in Wines Produced from Dehydrated Grapes of the Hybrid Variety ‘Hibernal’ as a Factor Determining the Method of Producing Straw Wines

Sweet wines are appreciated worldwide; many are produced by fermenting the must of dehydrated (semi-dried) grapes, using methods that vary from region to region. The aim of this study was to evaluate the basic chemical and oenological characteristics of wines obtained by three technologies of production. The wines were made from a hybrid cultivar ‘Hibernal’, grown under cool climate conditions. ‘Hibernal’ is a hybrid variety. This ‘Hibernal’ variety is widely cultivated in central and eastern Europe, where it is of great economic importance. Wines produced from this variety are popular in local markets. In comparison with the production of varieties belonging to Vitis vinifera, a very small percentage of the ‘Hibernal’ variety is cultivated. The methods used in the experiment for the production of wines were: classical method in the Italian passito style, modification of the passito style with a seven-day maceration of grapes, and a method of production in the Tokaj wine style at five Puttonyos. Basic chemical parameters, acid profile, total phenolic content, antioxidant and antiradical capacities, and quantitative analysis of selected polyphenols was performed. The sensory features and quality of the wines was assessed using a sommelier analysis based on The Wine & Spirit Education Trust guidelines. The results indicated that the seven-day maceration of the dehydrated grapes resulted in the highest polyphenol content, as well as the largest antioxidant and antiradical contents. The oenological evaluation of wines produced by the Tokaj method and Italian passito method with seven-day maceration found that the wines were appreciated due to their rich taste, flavor, and overall quality. The present study confirms the promising opportunities to obtain special sweet wine with a valuable composition and oenological characteristics in regions with cooler climates.

Aroma of Icewine: A Review on How Environmental, Viticultural, and Oenological Factors Affect the Aroma of Icewine

The aroma of a wine is mostly driven by not only the factors in the vineyard, such as the grape variety and harvest time, but also the fermentation process. Icewine is a unique, intensely sweet wine made from late harvested grapes that have frozen naturally on the vine. Different from normal table wines, the grapes used in icewine naturally undergo a dehydration process and freeze-thaw cycles, and the must for icewine making has to be pressed from frozen grapes. This pressing process leaves water behind as ice crystals and allows the grape juice to be concentrated with more sugars, acids, and other dissolved solids, resulting in a slower than normal fermentation. These special procedures can lead to a unique aroma characteristic of icewine. This review delves into recent advances in chemical compounds related to icewine aroma characteristics and addresses how changes in these aroma characteristics and composition are influenced by environmental, viticultural, and oenological factors in the vineyard and winery. Deficiencies in previous studies and future trends related to the flavor science of icewine were also briefly addressed.

Correlating Noble Rot Infection of Garganega Withered Grapes with Key Molecules and Odorants of Botrytized Passito Wine

Experimental passito wines with different percentages of naturally noble-rotten grapes of the Garganega variety were analyzed to evaluate key molecules and odorants related to the typical aroma and sensory profile of botrytized passito wine. Remarkable changes in the concentration of 1-octen-3-ol, 4-terpineol, benzaldehyde, N-(3-methylbutyl)acetamide, and sherry lactone 1 and 2 were observed between sound and noble-rotten wines. Wines were perceived to be different for floral, honey, figs, apricot, and caramel scents. By partial least square regression these descriptors were well correlated to samples. An important positive contribution of sherry lactones, N-(3-methylbutyl)acetamide, vanillin, benzaldehyde, and γ-butyrolactone to honey, apricot, and caramel was observed. It is conceivable that oxidative effects of Botrytis cinerea infection play an important role in the genesis of these chemical and sensory aroma markers. This study provides a predictive tool for winemakers that use natural grape withering to produce wines whose aroma profile is not standardized due to the seasonal variation of noble rot incidence.