Regionality in Australian Shiraz: compositional and climate measures that relate to key sensory attributes

Abstract

Background and Aims: Regional characters or the ‘terroir’ aspects of Shiraz are not well understood. This study aimed to characterise the chemical composition of wines from sites within six important Australian regions, and the climate profiles of the sites, and to determine how they relate to sensory differences. Methods and Results: For 22 commercially produced wines 70 chemical measures and 17 site- and season-specific climate indices were determined. Wines with stalky/cooked vegetal sensory properties had a higher concentration of cinnamate esters and dimethylsulfide, which through multivariate analyses was related to later budburst and time of harvest. Wines with a higher concentration of monoterpenes were associated with floral aroma. High radiation measures were linked to higher tannin, colour density, norisoprenoid compounds and phenylethyl acetate and to stronger dark fruit/dried fruit and tannin/colour attributes. High rainfall indices were generally related to low sensory attribute ratings and compositional measures. From cluster analysis of compositional data, wines were well grouped by region of origin. Conclusions: Distinctive chemical fingerprints exist for the regions studied, and their climatic profiles were strongly associated with wine composition, with key compounds influencing sensory differences. Significance of the Study: The approach of applying multiple site- and season-specific climate measures and relating these to chemical composition and the characteristic sensory attributes of regional Australian Shiraz wines can help producers better understand and influence the effect of place on their wines.