Malfeito Ferreira, ManuelRauhut, DorisPicard, David2016-02-102016-02-102015Picard, D. - Refining bretty wine. Aromatic integration of Brett matabolites through microoxygenation. Lisboa: ISA, 2015, 73 p.http://hdl.handle.net/10400.5/10898Mestrado em Viticultura e Enologia - Instituto Superior de Agronomia / Faculdade de Ciências. Universidade do PortoThis work scrutinises if and how microoxygenation can affect different Brettanomyces bruxellensis metabolites in red wine. Through an experimental research set-up using microfiltered tannin-rich red wine spiked with various concentrations of phenols, the work shows that microoxygenation technology adapted to small tanks helps to reduce vinyl compounds – the intermediary metabolite of the Brett metabolism – but not ethylphenol, which is chemically stable and difficult to bind. In the presence of oxygen, this reduction saw rates of up to 80% within a ten-day period. A follow-on experiment with sterile model wine further showed that the addition of oenological tannins and higher temperatures equally contribute to the reduction of vinylphenol, without producing additional ethylphenol. Aromatic integration, a concept by the American winemaker Clark Smith hence was caused only indirectly, through the reduction of vinyl compounds – and not as has been suggested by Smith through the integration of ethylphenol into the tannic structure of the wine. Building on these observations, a series of sensorial analysis panels with trained tasters from the universities of Geisenheim, Bordeaux, Lisbon and Changins demonstrated the social-cultural variability of aroma sweet spots for different types of bretty wine. While heavily phenolic characters were consistently rejected, wines with lower dosages of vinyl and ethyl compounds were considered as pleasantengaromatic integrationmicrooxygenationBrett metabolitesphenolic charactermaster thesis203651510