Determining wine aroma from compositional data

The value of, opportunities provided by, and the difficulties in elucidating the exact contribution that chemical compounds make to wine aroma and flavour are outlined and highlighted in this review. This paper provides an overview of the current understanding of relationships between wine sensory properties and volatile chemical composition through a discussion of recent studies where accurate, precise chemical data have been obtained for compounds shown by quantitative gas chromatography-olfactometry (GC/O) to be odour active in a sample. A centrepiece of this discussion is a compilation of compounds indicated to be most important to wine aroma. This is followed by a consideration of the limitation of odour activity values obtained by GC/O with particular reference to wine esters and volatile thiol compounds. The strengths of sensory descriptive analysis and its associated statistical methodologies to complement chemical composition data for aroma compounds are also explored. Grape flavour precursor compounds and the development of methods for their rapid quantification are then discussed in the context of the role of precursors contributing to wine aroma. Finally, an assessment is given of the likelihood in the near future of developing analytical strategies to measure wine flavour in relation to consumer expectations on the one hand, and on the other, to viticultural management practices to influence grape flavour composition.