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Background and Aims Ethyl carbamate (EC) is a known carcinogen that has been found in wines. The aims of this study were: (i) to study the effect of fermentation under different enological conditions on the EC concentration in sweet Sherry wines made from the two grape cultivars, Muscat and Pedro Ximenez, during three consecutive vintages (2008–2010); and (ii) to investigate the evolution of EC concentration during ageing in oak and in stainless steel. Methods and Results Before and during ageing, the wines obtained were periodically sampled, and EC content was determined by HPLC with fluorescence detection. Mean values of EC ranged from 6.16 μg/L for samples after alcoholic fermentation to 120 μg/L for samples after 28 months of ageing in oak. Data were submitted for ANOVA and cluster analysis. It has been observed that the various factors considered (vinification conditions, ageing type, ageing time, grape cultivar and vintage) have significant influence on the EC concentration of the wines. The use of Saccharomyces bayanus instead of Saccharomyces cerevisiae reduced the EC concentration significantly. Both the use of nutrients and skin contact with pectolytic enzymes increased EC concentration. Ageing increased the EC content for all vinification conditions. Conclusions Ageing was the most significant factor affecting EC concentration of the wines. Wines made from Muscat, fermented with S. cerevisiae and aged in oak cask for up to 28 months presented the highest EC concentration. Significance of the Study The ageing of sweet Sherry wines in oak results in a concentration of EC higher than that from ageing of similar wines in stainless steel.

Several experiments of aging in oak wood and stainless steel of sweet Sherry wines obtained from grapes cv. Muscat fermented under different enological conditions have been carried out. These wines were periodically sampled and their volatile content was analyzed using SBSE–GC–MS. A sensory study was also carried out. Data were submitted to different statistical techniques. An important influence of the three factors considered, fermentation type, aging type, and aging time, have been observed. In cluster analysis, the grouping obtained demonstrated that the volatile compounds considered possess sufficient explanatory power to detect the type of aging process and differentiate the two yeast strains studied. In the case of the linear discriminant analysis, high percentages of correct classification were obtained for the three factors considered. Taking into account the global volatile profile, the factor “aging type” (oak cask or stainless steel) has demonstrated the highest influence on the volatile content of the wines, with those wines from Experiments D4 and D5 (fermented with S. bayanus) and aged in oak wood clearly differentiated from those ones fermented with S. cerevisiae and aged in wood or stainless steel. From a sensorial point of view, the wines fermented with S. Cerevisiae and aged in wood (D1C and D2C) were the most valued ones.

Sweet Sherry wines from Pedro Ximenez and Muscat sun and chamber-dried grapes during vintages 2009 and 2010 were aged in American oak wood for 12 months. Their volatile content was periodically analyzed using SBSE-GC-MS. Cluster analysis and principal component analysis demonstrated that the volatile compounds considered can be used to detect grape variety and vintage. Principal component analysis for each grape variety, clearly differentiated aging time and vintage. Drying type was the least significant factor. Sweet wines produced using chamber driers were from Pedro Ximenez and Muscat grapes provides similar in volatile constituents as those produced by traditional process.

A study of accelerated aging on an industrial scale, employing both microoxygenation and oak chips, of a Sherry wine vinegar has been carried out. The effect of these two factors, microoxygenation and oak chips, on polyphenolic and volatile compounds, and sensorial parameters has been evaluated. The dose of oxygen applied to the vinegar and the use of chips provoke important changes in its content in polyphenols and volatile compounds and make it similar to the profile obtained using traditional aging. An alternative method of aging is proposed, using 5 g/L of chips and a dose of oxygen around 70 mL/L month. With the proposed method, and according to the sensorial and analytical results obtained, vinegars similar to those traditionally aged can be obtained by accelerated aging with microoxygenation and chips in shorter periods of time. In our case, a final reduction of 86% of time is achieved with the proposed method.