The effect of ripeness on the concentration of polyfunctional thiol precursors was investigated in 'Gewürztraminer' juices in two vintages characterised by very different climate conditions. An incremental trend of glutathionyl-3-mercaptohexan-1-ol and cysteinyl-3-mercaptohexan-1-ol during ripening was observed. The increase in the last phase of maturation was noticeable in both vintages. The concentration of 4-S-glutathionyl-4-methylpentan-2-one and 4-S-cysteinyl-4-methylpentan-2-one was confirmed to be low in 'Gewürztraminer', although the latter was found at quantifiable levels in a couple of samples. The management of the harvest date appears to be highly important in order to exploit the potential grapefruit-like note related to polyfunctional thiols of little aromatic 'Gewürztraminer' wines, particularly in case of challenging vintage years.
