PREVALENCE OF OAK-RELATED AROMA COMPOUNDS IN PREMIUM WINES
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
Accurate quantitative data is necessary to help understand the compounds which might influence these aromas but their analysis is often not a trivial undertaking. The furanones, especially furaneol, are difficult to measure accurately in wine as they are very polar. Thus, an improved stable isotope dilution assay was developed using automated liquid–liquid microextraction and multidimensional–gas chromatography–mass spectrometry. Also, the quantification of aldehydes was simplified using automated headspace solid-phase microextraction and gas chromatography–tandem mass spectrometry with invial derivatisation. Thiazoles were quantified utilising gas chromatography–tandem mass spectrome-try. Other targeted volatile compounds were quantified using previously published stable isotope dilution assay methods that are routinely used in-house. Wide concentration ranges were found for many of the targeted aroma compounds and this information will direct further detailed studies.
Issue: OENO Macrowine 2023
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oak barrel, wine, aroma compounds, quantitation