Impact of metal ions on wine quality

This project explores how the presence of metals can influence the ageing process of bottled wine, and provide options to minimise the detrimental influence of metals through wine production process.

The challenge

Metal ions naturally occur in grapes and wine, and are sometimes added during winemaking to repress the aroma of smelly sulfur compounds. Recommended metal concentrations in wine are given as broad ranges due to the complexity of their effects. This lack of understanding makes it difficult to predict wine ageing and shelf life, and to optimise metal concentrations in wine.

Project name: The impact of metal speciation on the development, shelf-life and sensory properties of wine (2018 -2024)

Funding Wine Australia $693,043

Our response

This project will investigate the influence of different metal species on the colour and flavour development in wine. The role of metal species on the consumption of oxygen and sulfur dioxide in red and white wines will also be expored. Additionally, the impact of ascorbic acid on copper(I) sulfide stability and activity will be assessed. By establishing a link between metal speciation and wine production steps, we seek to find efficient methods to control the specific metal species present in wine and juice. Trials will be conducted using typical winery scale production operations to identify the most effective ways to modify the metal profile of a wine. Through these efforts, the aim is to deepen the understanding of the complex relationship between metal ions and wine characteristics.

The goal

The goal is to provide valuable insights to meet the growing consumer demand for minimal winemaking intervention. By reducing input costs for wineries, we aim to positively impact wine quality by minimising the negative effects of metals during fermentation and bottle storage. The results from this study will contribute to enhancing the overall consumer experience and advancing the quality standards of wines.

Wine Australia

Our team

Principal scientist

Key research publications

Zhang, X., & Clark, A. (2023). Cu fractions in Shiraz and Pinot noir wines during bottle aging: rates of change and capacity for conversion. OenoOne, 57(4). https://doi.org/10.20870/oeno-one.2023.57.4.7425

Zhang, X., Blackman, J., & Clark, A. (2023). Ascorbic acid addition to rosé: Impact on the oxidative and reductive development of bottle wine. Food Chemistry, 424, 136418.  https://doi.org/10.1016/j.foodchem.2023.136418

Zhang, X., Langford, K., & Clark, A. (2022). Cu-organic acids in red wine after bottling: A time-line for inhibition of reductive aroma compounds. Poster session presented at 18th Australian Wine Industry Technical Conference and Trade Exhibition, Adelaide, South Australia, Australia. https://az659834.vo.msecnd.net/eventsairaueprod/production-awitc-public/b2d2faf691b14255bebdc70860f92dc9

Zhang, X., Blackman, J., & Clark, A. (2022). Reductive development of white wine during bottle ageing: The time-line of protection offered by specific Cu fractions. Abstract from 18th Australian Wine Industry Technical Conference and Trade Exhibition, Adelaide, South Australia, Australia. https://awitc.com.au/wp-content/uploads/2022/07/123_Zhang.pdf

Zhang, X., Blackman, J., Prenzler, P., & Clark, A. (2022). Reductive development of white wine during bottle ageing: Time-line of protection from specific Cu fractions. Poster session presented at 18th Australian Wine Industry Technical Conference and Trade Exhibition, Adelaide, South Australia, Australia.

Zhang, X., Bowyer, P., Scollary, G., Clark, A., & Kontoudakis, N. (2022). Sulfide-bound copper removal from red and white wine using membrane and depth filters: Impacts of oxygen, H2S-to-Cu ratios, diatomaceous earth and wine volume. Food Chemistry, 377, 1-10. [131758]. https://doi.org/10.1016/j.foodchem.2021.131758

Zhang, X., Blackman, J. W., Prenzler, P. D., & Clark, A. C. (2022). Suppression of reductive characters in white wine by Cu fractions: Efficiency and duration of protection during bottle aging. Food Chemistry, 393, 1-10. [133305]. https://doi.org/10.1016/j.foodchem.2022.133305

Zhang, X., Langford, K., & Clark, A. (2022). Cu-organic acids in red wine after bottling: A time-line for inhibition of reductive aroma compounds. Poster session presented at 18th Australian Wine Industry Technical Conference and Trade Exhibition, Adelaide, South Australia, Australia. https://az659834.vo.msecnd.net/eventsairaueprod/production-awitc-public/b2d2faf691b14255bebdc70860f92dc9

Zhang, X., Blackman, J., & Clark, A. (2022). Reductive development of white wine during bottle ageing: The time-line of protection offered by specific Cu fractions. Abstract from 18th Australian Wine Industry Technical Conference and Trade Exhibition, Adelaide, South Australia, Australia. https://awitc.com.au/wp-content/uploads/2022/07/123_Zhang.pdf

Zhang, X., Bowyer, P., Scollary, G., Clark, A., & Kontoudakis, N. (2022). Sulfide-bound copper removal from red and white wine using membrane and depth filters: Impacts of oxygen, H2S-to-Cu ratios, diatomaceous earth and wine volume. Food Chemistry, 377, 1-10. [131758]. https://doi.org/10.1016/j.foodchem.2021.131758

Zhang, X., Blackman, J. W., Prenzler, P. D., & Clark, A. C. (2022). Suppression of reductive characters in white wine by Cu fractions: Efficiency and duration of protection during bottle aging. Food Chemistry, 393, 1-10. [133305]. https://doi.org/10.1016/j.foodchem.2022.133305

Zhang, X., Blackman, J., Clark, A., & Scollary, G. (2022). The duration of protection offered by Cu against reductive character development during bottle aging of white wine. Wine and Viticulture Journal, 37(4), 28-32.

Zhang, X., Langford, K., & Clark, A. (2022). The inhibition of hydrogen sulfide and methanethiol accumulation in wine by Cu(II): The influence of temperature on the duration of protection.. Abstract from In Vino Analytica Scientia, Neustadt an der Weinstrasse, Germany. https://ives-openscience.eu/14128/

Zhang, X. (2022). The removal of specific fractions of Cu from wine.. Paper presented at 18th Australian Wine Industry Technical Conference and Trade Exhibition, Adelaide, South Australia, Australia. https://www.sciencedirect.com/science/article/abs/pii/S0308814621007706

Zhang, X., Kontoudakis, N., Clark, A., Bowyer, P., & Scollary, G. (2022). WINEMAKING COPPER SULFIDE Sulfide-bound copper removal from red and white wine by depth filtration. Wine and Viticulture Journal, 37(1), 32-34.

Clark, A., Kodoudakis, N., Zhang, X., & Scollary, G. (2021). An efficient method for the rapid assessment of free copper in white wine. Wine and Viticulture Journal, 36(1), 34-38. https://winetitles.com.au/wvj/articles/wine-viticulture-journal-volume-36-no-1-2021/an-efficient-method-for-the-rapid-assessment-of-free-copper-in-white-wine/

Clark, A., & Bekker, M. (2021). Metal ions and complexes. In P. Iland, D. Bruer, N. Bruer, C. Ford, & E. Wilkes (Eds.), Theory and concepts of chemical, physical and sensory analyses and tests of grapes and wine. (1 ed., Vol. 1, pp. 99-103). Patrick Iland Wine Promotions.

Zhang, X., Kodoudakis, N., Scollary, G., & Clark, A. (2021). Simplified method for the rapid quantification of copper fractions in wine. Vine and Wine Technical Reviews, 1-2. https://doi.org/10.20870/IVES-TR.2021.4698

Clark, A., & Zhang, X. (2021). Measurement and behaviour of Cu in wine. Paper presented at Enoforum USA, United States.

Zhang, X., Kodoudakis, N., Blackman, J., & Clark, A. (2021). Inhibition of reductive characters in wine by Cu-organic acids: Predicting the duration of protection. Abstract from Macrowine 2021. https://ives-openscience.eu/8213/

Clark, A., Zhang, X., & Kontoudakis, N. (2020). Simplified measures of copper fractions in wine: colorimetric and filtration-based approaches. Australian Journal of Grape and Wine Research, 26, 399-409.
https://doi.org/10.1111/ajgw.12450

Kontoudakis, N., Smith, M., Smith, P., Wilkes, E., & Clark, A. (2020). The colorimetric determination of copper in wine: total copper. Australian Journal of Grape and Wine Research, 26, 121-129.
https://doi.org/10.1111/ajgw.12425

Kontoudakis, N., & Clark, A. (2020). Sulfide-binding to Cu(II) in wine: Impact on oxygen consumption rates. Food Chemistry, 316, 126352.
https://doi.org/10.1016/j.foodchem.2020.126352

Zhang, X., Kontoudakis, N., Blackman, J., & Clark A. (2019). Copper(II) and sulfur dioxide in Chardonnay juice and Shiraz must: Impact on volatile aroma compounds and Cu forms in wine. Beverages, 5(4), 70.
https://doi.org/10.3390/beverages5040070

Kontoudakis, N., Schmidtke, L., Bekker, M., Smith, M., Smith, P., Scollary, G., Wilkes, E., & Clark, A. (2019) Analytical strategies for the measurement of different forms of Cu and Fe in wine: Comparison between approaches in relation to wine composition. Food Chemistry, 274, 89-99.
https://doi.org/10.1016/j.foodchem.2018.08.084

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