IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Struck flint aroma in Chardonnay wines: what causes it and how much is too much?

Struck flint aroma in Chardonnay wines: what causes it and how much is too much?

Abstract

Struck flint/struck match/gun smoke/mineral aroma is considered desirable in some styles of wines, with this character sometimes evident in wines such as Burgundian Chablis and cooler climate barrel-fermented Australian Chardonnay. Phenylmethanethiol (benzyl mercaptan) is a potent sulfur-containing volatile aroma compound and is thought to be responsible for struck flint character in wine. However, few studies targeting this character have been done. To address this, over 70 commercially available white wines, mostly Chardonnay, were chemically analysed to establish the variability of phenylmethanethiol, and the wines were assessed by a sensory panel to indicate whether there might be a transition from struck flint aroma to a less pleasant sulfurous/burnt aroma. Interestingly, another potent sulfur-containing aroma compound, 2-furylmethanethiol (furfuryl thiol), was also found in the wines and was at particularly high concentration in wines suggested as having high struck flint aroma. 2-Furylmethanethiol has previously been shown to form in white wines during alcoholic fermentation in the barrel from the furan-2-carbaldehyde (furfural) released by toasted oak staves reacting with the hydrogen sulfide produced by yeast. This survey highlighted that both phenylmethanethiol and 2-furylmethanethiol are linked to struck flint aroma but when higher levels of 2-furylmethanethiol are present, the character might tend toward sulfurous/burnt.

 There was also no information available on the effects of winemaking techniques and commonly used winemaking additives on the formation of phenylmethanethiol. Further investigations in model fermentations of its potential precursors benzaldehyde and hydrogen sulfide were conducted. Wine yeast strains that produced high concentrations of hydrogen sulfide resulted in higher concentrations of phenylmethanethiol during fermentation of a synthetic grape must and increasing concentrations of ammonia (YAN) promoted the formation of phenylmethanethiol by yeast during fermentation. Thus, different winemaking parameters could be used to modulate the concentrations of phenylmethanethiol in wine.

DOI:

Publication date: June 24, 2022

Issue: IVAS 2022

Type: Article

Authors

T. E. Siebert1*, D. Espinase Nandorfy1,2, A. G. Cordente1, L. Pisaniello1, F. T. Watson1, S. R. Barter1, D. Likos1, A. C. Kulcsar1, I. L. Francis1, and M. Z. Bekker1

1The Australian Wine Research Institute, Waite Precinct, Hartley Grove cnr Paratoo Road, Urrbrae 5064, Australia 
CASS Food Research Centre, School of Exercise and Nutrition Sciences, Deakin University 

Contact the author

Keywords

thiols, sensory, fermentation

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Monitoring of grapevine stem potentials with an embedded microtensiometer

Vine water status is a crucial determinant of vine growth, productivity, fruit composition and terroir or wine style; therefore, regulating water stress is of great importance. Since vine water status depends on both soil moisture and aerial environment and is very temporally dynamic, direct measurement of vine water potential is highly preferable. Current methods only provide limited data. To regulate vine water status it is critical to monitor vine water status to be able to: (1) measure vine water status to predict the effect of water stress on the overall vineyard performance and fruit quality and optimize harvest management and wine-making (2) properly regulate the water status to impose for a desired fruit quality or style (3) determine if water management has reached the desired stress level.

Mapping climate and bioclimatic indices at high-resolution in vineyard regions

Many of the world’s vineyard regions are located in regions of complex terrain, with the result there is significant local climate variation.

New tools for a visual analysis of vineyard landscapes?

A vineyard landscape is above all an area observed by someone, that is to say a physical entity perceved and represented by this person.

Impacts on water availability for vitiviniculture worldwide using different potential evapotranspiration methods

Beyond the sole warming globally perceived and monitored, climate change impacts water availability. Increasing heatwaves frequency observed during the last decades

The effects of calcite silicon-mediated particle film application on leaf temperature and grape composition of Merlot (Vitis vinifera L.) vines under different irrigation conditions

This study examined whether the application of calcite-silicon mediated particle film (CaPF) at veraison can mitigate a drought-induced increase in leaf temperature on grapevine, thus contributing to improved leaf functionality, yield and grape composition traits. A total of 48 five-year-old Merlot (Vitis vinifera L.)