Analytical characterization of Oloroso Sherry in Sherry Cask seasoning and its influence in the ageing of brandy de jerez

Abstract

Oloroso Sherry is a typical fortified wine from Jerez de la Frontera (south of Spain). It is one of the most used in the seasoning of oak barrels, called Sherry Cask, destined in this area for ageing brandies or condiments as wine vinegars. Brandy de Jerez is an European Geographical Indication for grape-derived spirits. Its special organoleptic characteristics are due to its traditional dynamic ageing in Sherry Casks. American oak is the most common wood employed in Jerez area, where Brandy de Jerez is exclusively manufactured. During ageing period of Sherry and brandies, the wood is not only a container, it is involved in several physicochemical process with the Sherry or the distillate. Oak wood is the responsible of the presence of many compounds in the products, affecting their aroma and chemical composition and having a high influence in their final quality. Moreover, the seasoned wood with Sherry wine could transfer the compounds from wine into the brandy, improving its aroma and flavor. The casks seasoned process with Oloroso Sherry is usually carried out following a static ageing system, known as Añadas, although the traditional dynamic system from Sherry area is also employed, known as Criaderas and Solera. The Brandy de Jerez ageing must be carried out in the Criaderas and Solera system. However, there are other brandies that can be aged in static systems. There are not many studies about the cask seasoning and its impact in brandy ageing. Due to the growing market and the current interest in the Sherry Casks, it is interesting to deepen the knowledge about them. In the present work, an analytical characterization of the Oloroso Sherry used in the seasoning casks process was carried out to determine how it affects the wine. The physicochemical characterization and the sensory analysis of brandy aged in Sherry Casks were also studied, evaluating how it modifies his organoleptic properties. The effect of the brandy ageing system was also evaluated. The casks had been seasoned during 4 years with Oloroso Sherry and the brandies were characterized after 1 year of ageing. Two ageing systems were used for the experiences: dynamic (Criaderas and Solera) and static (Añadas). The results have been also compared with brandy aged in new casks. Levels of potassium and tartaric acid in Oloroso Sherry decrease after 4 years of seasoning wood. Total and volatile acidity, glycerin, ethyl acetate, ethyl lactate, ethyl succinate, dry extract and PTI increase their concentration during the process.A similar evolution was observed between brandies aged in static and dynamic system. Comparing the results with brandies aged in new casks, big differences were found. The level of wood compounds detected in brandies aged in new casks were much larger than in brandies aged in seasoned casks. However, the brandies aged in used barrels were judged more balanced than those aged in new barrels.