The modification of cultural practices in grapevine cv. Syrah, does it modify the characteristics of the musts?

The wine yeast Saccharomyces cerevisiae can highly affect wine aromatic profile by producing and/or mediating the release of a whole range of metabolites (such as thiols, esters, and terpenes), which in turn contribute to enhanced aroma and flavor. These metabolites depend on yeast metabolism activated during fermentation which can constitute the ‘’metabolic footprint’’ of the yeast strain that carried out the process.

Varietal thiols 3-sulfanylhexan-1-ol (3SH), 3-sulfanylhexyl acetate (3SHA) and 4-methyl-4-sulfanylpentan-2-one (4SMP) are essential for fruity aromas of Sauvignon Blanc wines. The concentration of varietal thiols in wines was thought to be related to the concentration of their precursors in grapes, however only a small proportion of precursors are released to varietal thiols during fermentation. New findings suggested that specific grape juice metabolites could significantly impact on the development of three major varietal thiols and other aroma compounds of Sauvignon Blanc wines.

Aroma diversity is one of the most important features in the expression of the varietal and geographic identity and sensory uniqueness of a wine. Italy has one of the largest ampelographic heritages of the world, with more than five hundred different varieties. Among them, many are used for the production of dry still white wines, many classified as Protected Designation of Origins and therefore produced in specific geographical areas with well-defined grape varieties. Chemical and sensory characteristics of the aroma of these wines have never been systematically studied, and the relative diversity has never been described and classified.

Barrel fermentation and barrel-ageing of wine are commonly utilised practices in premium wine production. The wine aroma compounds related to barrel contact are varied and can enhance a range of wine aromas and flavours, such as ‘struck flint’, ‘caramel’, ‘red berry’, ‘toasty’ and ‘nutty’, as well as conventional oaky characters such as ‘vanilla’, ‘spice’, ‘smoky’ and ‘coconut’. A survey of commercially produced premium Shiraz, Cabernet Sauvignon, Pinot Noir and Chardonnay wines was conducted, assessing the prevalence of compounds that have been proposed as barrel-ageing markers¹ including oak lactones, volatile phenols, furanones, aldehydes, thiazoles2,3, phenylmethanethiol⁴ and 2-furylmethanethiol.⁵

Climate change has led to increased extreme weather events, such as severe droughts and intense rainfall, with regions like Alentejo and Algarve in Portugal, being particularly affected.