Aroma profile of oxidatively aged White and Tawny Port wines with different indication of age. Contribution of the non-rectified wine spirit

The aroma profiles of oxidatively aged White and Tawny Port wines with increasing indication of age were studied to understand differences in their ageing processes. Thirty-one and twenty-eight aroma compounds were quantified in Tawny and White Ports, respectively. Sotolon increased with age in both styles, contributing significantly to the aroma of older wines. Esters such as ethyl hexanoate, ethyl octanoate, and ethyl decanoate had odour activity values (OAVs) >1, especially in Tawny Ports, where their concentrations rose with age. In contrast, their levels declined in aged White Ports, reducing aromatic impact. 1,1,6-Trimethyl-1,2-dihydronaphthalene and β-damascenone also contributed to aroma due to their low odour thresholds. Differences in aroma evolution may be linked to differences in wine matrix composition. Non-rectified wine spirit used for fortification influenced the initial aroma through its higher alcohols and esters. Over time, oxidation-derived compounds became dominant, enhancing aromatic complexity and differentiating the wine styles.