Impact of alternative wood ageing systems in the odorant profile of wine spirits with GC-O analysis

Mestrado em Engenharia de Viticultura e Enologia (Double Degree) / Instituto Superior de Agronomia. Universidade de Lisboa / Faculdade de Ciências. Universidade do PortoTraditionally, wooden barrels are used in the ageing/maturation of wine and many more alcoholic beverages, especially wine spirits. However, production costs, as well as the general trend towards more sustainable management of forests and trees to produce such casks, have led the researchers to develop alternative methods for ageing and storing such beverages. In this study, it was examined the application of wooden staves on wine spirits in order to accelerate the ageing process. It was evaluated the sensory composition and the odourant compounds of wine spirit aged in the traditional system (barrels) compared to the alternative system (stave) using two type of wood: Limousin oak and Portuguese chestnut. The results of sensory analysis pointed out that the alternative ageing system with chestnut wood, bring to the wine spirit an accelerated and more complex ageing with concerning the attribute deriving from wood, namely vanilla, spicy, caramel, toasted, dry fruits, smoky, coffee. Also, the wine spirits from alternative ageing system with oak wood presented a good evolution, in comparison with those from t the chestnut barrels, particularly for toasted, spicy, vanilla, dry fruit and smoke notes. The GC-O analysis, permitted to detected and identified 23 odourant compounds, especially odourant with characteristic of fresh distillate with fruity and floral note deriving from fermentation process. Only a few odourant from wood (vanillin, HMF, syringaldehyde) was identified on the different samples. Nevertheless, the CA analysis for classify and find the difference between the ageing systems shown a low % of variance that didn’t permit to discriminate the samples. These results pointed out one of the limits of GC-O analysis: contrary to the sensorial profile where volatile compounds and no-volatile compounds interact each other, giving a general perception of the product, in the GC-O analysis the volatile compounds are evaluated separately. Anyway, this work is a first approach to this subject and further studies are required to study the differences between the ageing systems after two years or moreN/