Cultivar, site or harvest date: the gordian knot of wine terroir

The complex interactions of vine cultivars, and localised regional climate associated with specific vineyard sites are important attributes to the concept of terroir and significant contributors to grape maturity and wine sensory profiles. An improved understanding of the influence of each factor and their interactions is a challenging conundrum, and will enable more efficient production targeting specific wine styles.

To characterise the metabolic flux of grape berries and resulting wines to characterise the relative impact of site specific climate, cultivar, and grape maturity based upon berry sugar accumulation models that consistently target specific wine styles.

A spatial and temporal study of grape and wine composition was undertaken for two important cultivars in two distinct regions of New South Wales. Measures of composition and wine sensory ratings were simultaneously analysed using a multiblock algorithm taking advantage of the ANOVA framework to identify important contributions to wine style arising from grape maturity, vineyard site and cultivar.

A consistent flux of grape and wine constituents is evident for wine made from sequentially harvested grapes from the same vineyard with increasing levels of grape maturity. Contributions of region and vineyard site to wine style could also be elucidated. Differences in metabolite flux in grapes and resulting wines between cultivars growing in similar conditions are evident.

The combination of a metabolomics and multiblock data decomposition approach may be successfully used to profile and elucidate the contribution of abiotic factors to grape and wine composition and provide improved understanding of the terroir concept.