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…

Study of Malvasia di Candia Aromatica shelf-life: effect of time and temperature on aroma compounds through an HS-SPME GCxGC-Ms approach

Young white wines should be consumed within a short time after bottling to avoid loss of their fresh, fruity attributes. Shelf-life of white wines can be extended if they are stored under suitable conditions of time and temperature prior to consumption.

Effect of oenological tannins on wine aroma before and after oxidation: a real-time study by coupling sensory (TDS) and chemical (PTR-ToF-MS) analyses

Polyphenols are important compounds involved in many chemical and sensory wine features. In winemaking, adding oenological tannins claims to have positive impacts on wine stability, protection from oxidation and aroma persistence. Polyphenols are antioxidant compounds by either scavenging reactive oxygen and nitrogen species or chelating Fe2+ ions (1). However, as tannins oxidation leads to the formation of highly reactive species (i.e. ortho-quinones), it is still unclear if they have an effective role toward oxidation of wine aromas (2). In this work, we aim at studying the effect of two commercial tannins (proanthocyanidins, ellagitannins) on red wine flavour (mainly aroma) before and after air exposition.

Irrigation as a tool for heatwave mitigation: the effect of irrigation intensity and timing in Cabernet Sauvignon

Heatwave events, defined as 2 or more days reaching ≥ 38 °C, are an increasingly frequent phenomenon threatening grape production worldwide. Heat stress has been shown to have negative consequences on grapevine physiology, leading to increased evaporative demand and intensified water stress. Due to heatwaves overlapping with important stages of grapevine reproductive development, spanning from berry set to the ripening stage, severe heat can potentially compromise yield and grape quality. The physiological response of grapevine to heat stress suggests a potential use of irrigation to mitigate heatwaves, however there is limited information regarding the irrigation amounts and timings needed for this purpose. Following up on a pivotal trial conducted between 2019 and 2022, in this study irrigation treatments with varying intensity and timing of application were refined to determine their potential mitigation of heat-associated damage to yield and fruit composition.

Texas terroir: gis characterization of the texas high plains ava

The Texas High Plains AVA is one of eight officially recognized wine regions in Texas, established in 1993. Six local wineries, including the second-largest in Texas, are supported by approximately 50 vineyards, which are also major suppliers of grapes to Texas wineries outside the region.

IMPACT OF THE WINES’ QUALITY ON THE WINE DISTILLATES’ ORGANOLEPTIC PROFILE

Brandy de Jerez (BJ) is a spirit drink made exclusively from spirits and wine distillates and is characterized by the use of casks for aging that previously contained Sherries. The quality and sensory complexity of BJ depend on the raw materials and some factors: grape variety, conditions during processing the wine and its distillation, as well as the aging in the cask. Therefore, the original compounds of the grapes from which it comes are of great interest (1 y 2) being in most cases the Airén variety. Their relationship with the quality of the musts and the wines obtained from them has been studied (3) and varies each year of harvest depending on the weather conditions (4).