IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 The inhibition of hydrogen sulfide and methanethiol accumulation in wine by Cu(II): The influence of temperature on the duration of protection

The inhibition of hydrogen sulfide and methanethiol accumulation in wine by Cu(II): The influence of temperature on the duration of protection

Abstract

Hydrogen sulfide and methanethiol are recognised as two of the most significant contributors to reductive off-flavours in wine. Cu(II) in wine is known to interact with both sulfhydryl compounds, lowering the concentration of their aroma-active forms while transitioning Cu(II) to a sulfhydryl-bound form. Both hydrogen sulfide and methanethiol can form during the aging of wine in low oxygen conditions, such as during bottle aging, and
their production is known to be accelerated by wine storage temperature. Consequently, the protection offered by Cu(II) to inhibit accumulation of the reductive aroma compounds during bottle aging will be limited by the Cu(II) concentration at the bottling and of rate sulfhydryl compound formation. Although insights have been made on the typical rates of binding of Cu(II) in wines in cellar conditions (i.e., 14 °C), the impact of elevated storage
conditions is not certain, but likely to influence the duration of time that Cu(II) can inhibit reductive wine characters. This study determines the rates of Cu binding during the storage of wine at variable temperatures.

Four red and three white wines were bottled with low (< 0.2 mg/L) and high (0.6 mg/L) Cu(II) concentrations. The wines were stored at 14 °C and 40 °C and measured at 0, 1, 3, 7 and 12
months, and 0, 3, 5 and 12 days, respectively. The different forms of Cu were quantified by colorimetry for white wine, and stripping potentiometry for red wine, and enabled calculation of Cu(II) binding rates during wine aging and estimation of activation energies for binding. The formation of free and salt-releasable hydrogen sulfide and methanethiol were determined by gas chromatography with chemiluminescence detection.

The results showed that the rate of Cu(II) binding was dramatically higher at 40 °C than 14°C, with complete binding of Cu(II) in the order of 3 – 8 months and 1 – 5 days, respectively, for the wines bottled with high Cu(II). The relative order of Cu(II) binding rates amongst wines was temperature dependent, whereby Cu(II) binding rates became more uniform across wines when stored at the higher temperatures. This implied limitations in utilising high storage temperatures to predict Cu(II) binding at lower storage temperatures. The accumulation of the aroma active forms of sulfhydryl compounds, that is, the free hydrogen
sulfide and free methanethiol, only occurred after Cu(II) was converted to its bound form and then also required a further lag time. These results provide critical insights into the time-line of protection afforded to wines by Cu(II) against the emergence of reductive characters during bottle aging.

DOI:

Publication date: June 23, 2022

Issue: IVAS 2022

Type: Article

Authors

Zhang Xinyi1, Langford Kylie2 and Clark Andrew C1

1Gulbali Institute, Charles Sturt University, School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
2Treasury Wine Estates, 97 Sturt Highway, Nuriootpa, SA 5355, Australia

Contact the author

Keywords

Copper, reduction, hydrogen sulfide, methanethiol, bottle-aging

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Understanding novel germplasm solutions: sensory, chemical and preliminary hedonic insights of wines made from Australian first-generation mildew resistant cultivars

One of the major issues for wine production in Australia is the management and eradication of powdery and downy mildews and the associated yield losses they present, costing Australian grape growers upwards of AUD$160M per annum [1].

Effect of ozone treatments in wine production of young and short-term aged white wines: destructive and non-destructive evaluation of main quality attributes

The main aim of WiSSaTech project (PRIN P2022LXY3A), supported by Italian Ministero dell’Università e della Ricerca and NextGenerationEU program, is to investigate eco-friendly and safe alternatives to sulphur dioxide (SO2) in wine production.

Consistency of the hydraulic traits and stomatal responses in grapevines with contrasting hydraulic vulnerability

Different from wild species in arid and semiarid conditions, cultivated species are very sensitive to drought and, beyond some stress thresholds, food production is not possible

Bio-protection by one strain of M. Pulcherrima: microbiological and chemical impacts in red wines

In oenology, bio-protection consists in adding bacteria, yeasts or a mixture of microorganisms on grape must before fermentation in order to reduce the use of chemical compounds such as sulphites.

The influence of different fertiliser applications and canopy management practices on the potassium content and pH of juice and wine of Vitis vinifera L. cvs. Cabernet-Sauvignon and Cabernet franc

In an attempt to reduce the pH of juice and wine, different fertiliser applications and canopy management practices were evaluated in South Africa in a field trial. Fertiliser treatments entailed no, CaSO4, Ca(OH)2, and MgSO4 fertilisation.