Analytical Characterisation of Selected Alternative Wood Species and Their Suitability for Oenological Applications Using Austrian Grüner Veltliner Wine

In response to growing consumer expectations for greater diversity and novel flavour profiles in wines, this study explored the use of alternative wood species in oenology. The effects of six alternative wood species – sweet chestnut, common hazel, Robinia, blackcurrant, vineyard peach, and grapevine – on Austrian Vitis vinifera L. cv. Grüner Veltliner wine were examined after a 98-day contact period using both toasted and untoasted wood chips. The aim was to characterise the similarities of these alternative wood species to traditionally used oak. A comprehensive analytical profiling was conducted, quantifying over 50 wood-associated compounds, including hydroxycinnamic and benzoic acids, ellagitannins, lactones, carbonyl compounds and volatile phenols. Currently, only oak and sweet chestnut are approved by the International Organisation of Vine and Wine for oenological applications, with wood chips permitted exclusively from the genus Quercus. Based on the results, toasted sweet chestnut was the most promising alternative species for use as wood chips. It enhanced the wine colour intensity more effectively than oak, while its phenolic composition, particularly catechin levels and hydroxycinnamic acids, aligned moderately with oak. Furthermore, wine treated with toasted sweet chestnut presented comparable concentrations of vescalagin and castalagin. The similar levels of carbonyl compounds, such as furfural, further underlined its suitability. Although volatile phenol levels, including vanillin, exceeded those of oak, wine treated with toasted sweet chestnut remained comparable in its overall composition. Based on these findings, toasted sweet chestnut is recommended for approval as wood chips, although additional sensory and toxicological studies are necessary to substantiate this recommendation.