2018 AWRI Reports
Varela, C. Bartel, C., Borneman, A., Herderich, M., Johnson, D. Brettanomyces yeasts still have potential to give wine producers a headache Wine & Viticulture Journal 33 (3), 36-38; 2018.
Abstract: Spoilage of wine by Brettanomyces yeasts remains a challenge for winemakers. Current strategies to minimise the risk of spoilage do not eliminate Brettanomyces yeasts from wineries and are heavily reliant on the preservative sulfite to stabilise wine against Brettanomyces growth. Researchers at the AWRI have demonstrated that existing Brettanomyces wine strains have the potential to evolve greater tolerance to sulfite and have found preliminary evidence that this may be occurring in industry. These findings highlight the importance of judicious use of sulfite and the need to continue to evaluate sulfite alternatives.
Capone, D., Pearson, W., Bindon, K., Kassara, S., Francis, L., Herderich, M., Johnson, D. What makes a red wine green? Wine & Viticulture Journal 33 (2), 32-35; 2018.
Abstract: A multi-pronged approach to researching ‘green’ flavours in red wines is paying dividends for researchers and wine producers. Innovative sensory approaches have led to new understanding of what is meant by the terms ‘green’ and ‘green tannin’ in wine. Experiments looking at inclusion of stems and leaves in ferments and the influence of local vegetation on wine flavour have contributed insight into the origin of ‘green’ flavours and how winemakers may be able to manage them to achieve a desired style.
Gawel, R., Schulkin, A., Smith, P., Kassara, S., Francis, L., Herderich, M., Johnson, D. Influence of wine polysaccharides on white and red wine mouthfeel. Wine & Viticulture Journal 33 (1), 34-37; 2018.
Abstract: Mouthfeel attributes such as viscosity, astringency and hotness play an important role in wine quality and are known to be influenced by the macromolecules present in wine. Several studies investigated the sensory impact of adding polysaccharides to a range of model and real wines. While some impacts were seen on the perception of viscosity and hotness, the basic wine matrix (pH and alcohol) had a much greater effect on mouthfeel and taste than the polysaccharides. Higher pH wines generally had greater perceived viscosity, bitterness and lower astringency, and higher alcohol wines were perceived as more bitter, astringent and hot. Winemaking practices that increase the concentration of certain polysaccharides have potential to mask palate hotness in both white and red wine, but practices that change wine pH and alcohol will probably have a greater impact.
2017 AWRI Reports
Struck match, freshness and tropical fruit: thiols and Chardonnay flavour
Capone, D., Francis, L., Williamson, P., Herderich, M., Johnson, D. Struck match, freshness and tropical fruit: thiols and Chardonnay flavour. Wine & Viticulture Journal 32 (6), 31-35; 2017.
Abstract: Chardonnay is the most planted white grape variety in Australia, but understanding of its flavour and aroma chemistry has been limited. Recent research at the AWRI has highlighted the importance of ‘thiols’ (a class of sulfur-containing compounds, previously thought to be important mainly in Sauvignon Blanc) in Chardonnay flavour. These compounds can contribute to overall wine freshness, ‘fruity’ characters, ‘flint/struck match’ notes and less desirable ‘box hedge/cat pee’ characters.
Schmidt, S., Borneman, A., Kolouchova, R., McCarthy, J., Bellon, J., Herderich, M., Johnson, D. Spoilt for choice: picking the right yeast in a vibrant market. Wine & Viticulture Journal 32 (5), 35-38; 2017.
Abstract: Winemakers have access to a wide array of different yeasts, but it can be difficult to choose the best yeast for a particular must. The yeast research program at the AWRI has employed new techniques to assess large numbers of commercially available wine yeast, to understand their performance under different conditions and the genetic basis for their behaviour. Results will give winemakers more information on which to base yeast choice and also help guide the development of future yeast strains.
Coulter, A., Cowey, G., Petrie, P., Essling, M., Holdstock, M., Stockley, C., Simos, C., Johnson, D. Vintage 2017 – observations from the AWRI helpdesk. Wine & Viticulture Journal 32 (4), 29-31; 2017.
Abstract: Since 1955 the AWRI has provided technical support to Australia’s grapegrowers and winemakers. The AWRI helpdesk responds to queries, conducts investigations and monitors technical trends across the nation’s wine regions, disseminating information via eBulletins, the AWRI website, webinars and face-to-face extension events. This article examines some of the technical challenges encountered by growers and winemakers during vintage 2017, which will be remembered as a cooler, later and slower vintage in many regions.
Stockley, C., Johnson, D. WineHealth 2017 – Navigating the health effects of alcohol consumption. Wine & Viticulture Journal 32 (3), 26-30; 2017.
Abstract: In February, the WineHealth 2017 international wine and health conference was held in Spain, the eighth in a series held since 1996. Approximately 200 delegates debated and discussed the latest data presented on the health effects of alcohol consumption, and considered future research directions. This article provides a summary of the trends discussed at that conference.
Bindon, K., Smith, P., Schulkin, A., Dambergs, B., Kassara, S., Barter, S., Solomon, M., Cynkar, W., Capone, D., McRae, J., Francis, L., Robinson, E., Johnson, D. Exploring the potential for grape objective measures to predict wine grade and style. Wine & Viticulture Journal 32 (2), 46-47; 2017.
Abstract: Grape composition is a primary determinant of the wine style achieved following winemaking yet, in Australia, grape assessment is largely subjective. A recent study at the AWRI investigated the use of objective chemical and spectral measures to predict existing subjective grape grading allocations. Both chemical and spectral analytical approaches were shown to be useful for grape grade prediction. This work was then extended to assess the possibility of predicting wine grade and/or style from grape analysis, with results showing that grape compositional measures have potential to be used to support decisions about streaming fruit to wine styles or grades. A new project, focussing on Shiraz, has recently been launched to investigate applying this knowledge through collaborations with a large wine producer in South Australia.
Longbottom, M., Robinson, E., Johnson, D. Building resilience in the face of a changing climate Wine & Viticulture Journal 32 (1), 32-34; 2017.
Abstract: A three-year extension project, funded by the Australian Government, delivered targeted technical information about greenhouse gas (GHG) emissions and climate change to the Australian grape and wine community. Positive messaging and some innovative extension mechanisms led to success in raising awareness and promoting practice change. New partnerships and the strengthening of Entwine, the Australian grape and wine industry’s sustainability program, will ensure continuing efforts in this area.
2016 AWRI Reports
Wine pH, copper and ‘reductive’ aromas in wines
Bekker, M.Z., Smith, P.A., Wilkes, E.N., Johnson, D.Wine pH, copper and ‘reductive’ aromas in wines Wine & Viticulture Journal 31 (6), 36-38; 2016.
Abstract: Managing wine pH is important for nearly all aspects of winemaking, including protection against microbial spoilage, colour stability, tartrate precipitation and wine aroma and flavour. Recent research at the AWRI has investigated the effects of wine pH and the interaction between wine pH and copper on the formation of ‘reductive’ aromas post-bottling in Chardonnay and Shiraz wines. Elevated residual copper concentrations were associated with increased hydrogen sulfide (H2S), methanethiol (MeSH), and carbon disulfide (CS2) concentrations; however, when the pH was lowered to 3.0, significantly less H2S and MeSH were produced. Dimethyl sulfide (DMS) was not affected by copper additions; however, at lower pH up to 27% less DMS was produced in Shiraz wines after six months of storage.
Cordente, T., Solomon, M., Godden, P., Curtin, C., Johnson, D. A rose by any other name: novel wine yeast that impart floral aromas Wine & Viticulture Journal 31 (5), 39-40; 2016.
Abstract: While there is substantial variation amongst existing wine yeast strains in their capacity to influence wine style, some desirable flavour compounds are not produced at concentrations where they significantly impact wine style. As part of ongoing yeast strain development projects at the Australian Wine Research Institute, novel wine yeast that make ‘floral’/’rose’ aroma compounds have been generated.
Coulter, A. Cowey, G., Petrie, P., Essling, M., Holdstock, M. Stockley, C., Simos, C. Johnson, D. Vintage 2016 – observations from the AWRI helpdesk Wine & Viticulture Journal 31 (4), 43-45; 2016.
Abstract: Since 1955 the AWRI has provided technical support to Australia’s grapegrowers and winemakers. The AWRI helpdesk responds to queries, conducts investigations and monitors technical trends across the nation’s wine regions, disseminating information via eBulletins, the AWRI website, webinars and face-to-face extension events. Vintage 2016 showed some similarities to vintage 2015, with an early and compressed harvest, rain close to harvest in certain areas and some concerns about bushfire smoke.
Borneman, A., Herderich, M., Johnson, D. Wine yeast: Where are they from and where are we taking them? Wine & Viticulture Journal 31 (3), 47-49; 2016.
Abstract: Advances in DNA sequencing have allowed analysis of the genomes of large numbers of wine yeast strains for the first time. Results show that wine yeast have low genetic variation compared with the overall genetic diversity of the species Saccharomyces cerevisiae (which also encompasses brewing, baking, sake and palm wine yeasts). This new understanding will be harnessed in future yeast breeding programs.
Wilkes, E., Day, M., Herderich, M., Johnson, D. In vino veritas – investigating technologies to fight wine fraud Wine & Viticulture Journal 31 (2), 36-38; 2016.
Abstract: Many of the great wines of the world have been subject to claims of substitution or counterfeiting, damaging the reputation of the affected brands and countries of origin. This article describes recent work at the AWRI looking at analytical approaches to determine the origin of wine that could form an important part of global efforts to fight wine fraud.
Abbott, T., Longbottom, M., Wilkes, E., Johnson, D. Assessing the environmental credentials of Australian wine Wine & Viticulture Journal 31 (1), 35-37; 2016.
Abstract: Life cycle analysis (LCA) is a method for assessing the environmental impact of a product or process, taking into account all of the steps from ‘cradle to grave’. While LCA has been used to assess specific Australian wine products in the past, this is the first time the method has been used to examine the environmental impact of the Australian wine industry as a whole. An indicative carbon footprint of Australian wine was calculated and found to be relatively low, but the analysis also identified particular ‘hot spots’ where improvements could be realised.
2015 AWRI Reports
Applying the latest understanding of grape composition
Smith, P., Schulkin, A., Kassara, S., Barter, S., Soloman, M., Cynkar, W., Capone, D., Francis, L., Bindon, K., Johnson, D. Applying the latest understanding of grape composition Wine & Viticulture Journal 30 (6), 33-38; 2015.
Abstract: A wide range of compounds that contribute to wine’s appearance, aroma, flavour and texture are derived from compounds present in grapes. Quite a lot is now known about these compounds, their origin, how to measure them and how to influence their concentration through viticultural and/or winemaking practices. This article describes how key grape-derived compounds influence wine and discusses a project that is applying the latest compositional knowledge to improve the objectivity of measures of grape quality and style.
Reschke, S., Tran, T., Bekker, M., Wilkes, E., Johnson, D. Using copper more effectively in winemaking Wine & Viticulture Journal 30 (5), 35-37; 2015.
Abstract: Winemakers commonly add copper to wines before packaging to remove unpleasant ‘reductive’ aromas. However, residual copper in wine can have negative consequences including unsightly deposits, increased risk of oxidation and the formation of further reductive compounds. This article reports a pilot study examining the effectiveness of making copper additions during fermentation and using the yeast present to bind up and remove the added copper from the final wine.
Coulter, A., Cowey, G., Petrie, P., Essling, M., Holdstock, M., Stockley, C., Simos, C., Johnson, D. Vintage 2015 – observations from the AWRI helpdesk Wine & Viticulture Journal 30 (4), 34-37; 2015.
Abstract: The AWRI helpdesk provides technical support to Australia’s grapegrowers and winemakers and monitors technical trends across the nation’s wine regions. During vintage 2015, helpdesk enquiries were again dominated by issues related to weather events, in particular rain and bushfires. The helpdesk responds to individual queries on a confidential basis, but also provides the latest information to industry via eBulletins, the AWRI website, webinars and face-to-face extension events.
Borneman, A., Bartowsky, E., Costello, P., Sternes, P., Chambers, P., Herderich, M., Johnson, D. Unravelling the capricious nature of Oenococcus oeni Wine & Viticulture Journal 30 (3), 34-37; 2015.
Abstract: Exciting times lie ahead for malolactic fermentation (MLF) research and this will bring substantial benefits to winemakers. New genetic sequencing techniques are revealing the incredible diversity amongst strains of Oenococcus oeni, the bacterium primarily responsible for MLF. This new knowledge should provide extensive opportunities for Australian winemakers to choose MLF strains tailored to suit their individual conditions – optimising both fermentation efficiency and flavour release.
Tran, T., Wilkes, E., Johnson, D. Microbiological stability of wine packaging in Australia and New Zealand Wine & Viticulture Journal 30 (2), 46-49; 2015.
Abstract: One of the last processing steps that takes place before a wine reaches a consumer is the packaging process. Whether a wine goes into a cask, bottle or other vessel, the decisions and processes carried out at the point of packaging will have a significant impact on the characteristics of the wine when it is consumed. Ensuring that wines are free from microbes that can grow in the packaged product is one of the key considerations of the packaging process, and one of the more difficult to manage. This article presents knowledge gained through the conduct of microbiological audits of packaging processes across the Australian and New Zealand wine industries. It includes a brief overview of industry practices, some common misconceptions regarding the microbiology of bottling and an audit case study.
Godden, P., Scrimgeour, N., Wilkes, E., Cynkar, W., Johnson, D. Applying spectral technology to improve winemaking efficiency Wine & Viticulture Journal 30 (1), 28-32; 2015.
Abstract: Spectral technologies have been developed for the rapid and simultaneous analysis of sugar and colour levels in red grape homogenates, and of yeast assimilable nitrogen (YAN) and other compositional variables in white juice. The technologies have been extensively trialled in large wineries over several vintages, with useful data obtained in real time. This ongoing work demonstrates the significant potential of spectral analysis to replace many expensive and time-consuming traditional laboratory methods, providing winemakers with opportunities to optimise winemaking processes.
2014 AWRI Reports
Exploring oxygen’s influence
Smith, P., Day, M., Schmidt, S., Bindon, K., Kassara, S., Schulkin, A., Kolouchova, R., Wilkes, E., Herderich, M., Johnson, D. Exploring oxygen’s influence Wine & Viticulture Journal 29 (6), 33-36; 2014.
Abstract: There are a number of unanswered questions about oxygen’s role in the winemaking process. How much oxygen gets into juice through production? What does juice exposure to oxygen do to final wine style and composition? What does oxygen exposure during fermentation do to wine style? Can oxygen be better measured during winemaking or markers for exposure be identified? This article presents results from the first stage of a research program at the AWRI investigating influences on wine style from management of oxygen during winemaking.
Curtin, C., Borneman, A., Zeppel, R., Cordente, T., Robyn, K., Chambers, P., Herderich, M., Johnson, D. Staying a step ahead of ‘Brett’ Wine & Viticulture Journal 29 (5), 34-37; 2014.
Abstract: Brettanomyces bruxellensis (known in the wine industry as ‘Brett’) is a species of yeast that produces unpleasant medicinal and phenolic characters in wine. While there are practical steps to be taken in the winery that are currently successful at controlling ‘Brett’, there is a risk that a strain could emerge that is resistant to control strategies. For that reason, research is under way to understand this yeast at the genetic level and make sure winemakers can stay ahead of any ‘Brett’ threat.
Coulter, A., Cowey, G., Dry, P., Essling, M., Holdstock, M., Stockley, C., Simos, C., Johnson, D. Vintage 2014 – Trends from the AWRI helpdesk Wine & Viticulture Journal 29 (4), 34-36; 2014.
Abstract: The AWRI helpdesk provides technical support to Australia’s grapegrowers and winemakers and monitors technical trends across the nation’s wine regions. During vintage 2014, helpdesk enquiries were dominated by issues related to extreme weather events including frosts, heatwaves and bushfires. A regulatory issue concerning changes to the limits for copper, iron and manganese in wines exported to China also raised significant concern. The helpdesk responds to individual queries on a confidential basis, but also provides the latest information to industry via emails, the AWRI website, webinars and face-to-face extension events.
Gawel, R., Godden, P., Williamson, P., Francis, L., Smith, P., Waters, L., Herderich, M., Johnson, D. Influence of phenolics on white wine quality and style Wine & Viticulture Journal 29 (3), 34-36; 2014.
Abstract: The importance of phenolic compounds in red wine colour and texture is well known. For white wines the story has not been as well understood. Texture in white wines is seen as positive, but coarseness and hardness are not. AWRI researchers have studied the effects of phenolics in commercial white wines, finding out about their effects on wine style, consumer liking and winemaker assessments.
Smith, P., Bindon, K., McRae, J., Kassara, S., Johnson, D. Tannin: impacts and opportunities along the value chain Wine & Viticulture Journal 29 (2), 38-41; 2014.
Abstract: Studying tannins is challenging. Their behaviour is rarely predictable; results can be contradictory and experiments often seem to generate just as many questions as they answer. But if you step back and take a broader view of the tannin research conducted over the past few years, you can see that real progress has been made in understanding tannin at key points across the grape and wine value chain, with practical outcomes for growers and winemakers.
Viviers, M., Smith, M., Wilkes, E., Smith, P., Johnson, D. The role of trace metals in wine ‘reduction’ Wine & Viticulture Journal 29 (1), 38-40; 2014.
Abstract: Copper salts have traditionally been added to wines to remove unpleasant volatile sulfur aromas. However, investigations of interactions between metals and volatile sulfur compounds are now revealing that metals can also promote the formation and release of these unwanted aroma compounds, particularly in low oxygen storage environments. Winemakers can minimise the risk of ‘reductive’ aromas by managing the timing of any copper additions and taking steps to minimise metal concentrations.
2013 AWRI Reports
Optimising fermentation through simulation
Muhalck, R., Scrimgeour, N., Wilkes, E., Godden, P., Johnson, D. Optimising fermentation through simulation Wine & Viticulture Journal 28 (6), 38-43; 2013.
Abstract: What if winemakers had advance warning of sluggish fermentation? What if winemakers could predict when a wayward ferment might arise and take steps to prevent it, before it happened? The AWRI Ferment Simulator is a powerful new weapon in the winemaker’s arsenal. lt can be used to predict ferment behaviour, test and evaluate alternative ferment management strategies, and monitor refrigeration and electricity demand so that corrective action can be taken on time and on target.
Borneman, A., Herderich, M., Johnson, D. The DNA of innovation Wine & Viticulture Journal 28 (5), 52–56; 2013.
Abstract: Winemaking is arguably the world’s oldest biotechnology, with a history dating back more than 7000 years. The past century has seen unprecedented advances in wine research with the advent of genomics and DNA sequencing. These technologies stand to transform our understanding of wine yeast, boost efforts to combat pests, diseases and contaminants and provide greater insight into wine character, regionality and terroir. This AWRI Report explains how and why DNA sequencing technologies are relevant to grape and wine producers and outlines their potential for the future.
Hoxey, L., Stockley, C., Wilkes, E., Johnson, D. What’s in a label? How science is helping winemakers to respond to new EU rules concerning allergens in wine Wine & Viticulture Journal 28 (4), 38-41; 2013.
Abstract: on 1 July 2012, new rules came into force regarding the labelling of potential allergens in wine exported to the European Union. The AWRI developed and validated a test for milk and egg residues to allow Australian producers to measure the levels of allergens in their wines and give consumers and policymakers continued confidence in Australian wine. Through national and international collaborations, work is also under way to ensure that testing is equally robust overseas.
Longbottom, M., Simos, C., Krstic, M., Johnson, D. Grape quality assessments: a survey of current practice Wine & Viticulture Journal 28 (3), 33-37; 2013.
Abstract: There is room for improvement in winegrape assessment procedures according to a new survey, detailed in this report. With responses from grape and wine producers throughout Australia – with various roles in grape production, supply and purchase – the survey indicates that there is industry-wide support for a standardisation of assessment methods and procedures to ensure consistency, accuracy and transparency for all.
Gawel, R., Day, M., Schulkin, A., Smith, P., Herderich, M., Johnson, D. The science of texture. Wine & Viticulture Journal 28 (2), 30–34; 2013.
Abstract: Astringency, viscosity, oiliness, hotness and bitterness: these ‘textures’ influence white wine consumers and contribute to wine style. But what makes a wine ‘textural’? Phenolics, acidity and alcohol play important roles, but how? To find out, researchers at the AWRI measured their effect on white wine texture and analysed interactions between them. A major finding was that some phenolics reduce rather than increase astringency and hotness of white wine.
Parker, M., Baldock, G., Hayasaka, Y., Mayr, C., Williamson, P., Francis, I.L., Krstic, M., Herderich, M., Johnson, D. Seeing through smoke. Wine & Viticulture Journal 28 (1) : 42–46; 2013.
Abstract: As a result of bushfires and controlled burning, winemakers and grapegrowers are seeking more information about the effects of smoke on ripening grapes, wine composition and sensory qualities. What is the relationship between smoke taint and smoke exposure? How does smoke interact
with grape and vine development? Research at the AWRI has led to the development of strategies to identify smoke exposure and a deeper understanding of smoke taint. This new insight is being used to provide advice and assistance to grape and wine producers.
2012 AWRI Reports
Robinson, E., Scrimgeour, N., Marangon, M., Muhlack, R., Smith, P., Godden, P., Johnson, D. Beyond Bentonite. Wine & Viticulture Journal 27 (6) : 20–26; 2012.
Abstract: Until now, bentonite treatment has been the winemaker’s best answer to troublesome haze-causing proteins. Breakthroughs in understanding the structure and properties of those proteins at the AWRI have led to the discovery of a potentially viable and practical alternative. Laboratory, pilot and industry scale trials of proctase have been successfully completed.
Black, C. Francis, L. Henschke, P. Capone, D. Anderson, S. Day, M. Holt, H. Pearson, W. Herderich, M. Johnson, D. Aged Riesling and the development of TDN Wine & Viticulture Journal 27 (5) : 20–26; 2012.
Abstract: Understanding and managing aged Riesling flavour has proven to be both complex and elusive. Some older Riesling wines have been described as having an aroma of ‘kerosene’, while most winemakers will describe the wines as displaying toasty, lime/marmalade flavours. This AWRI report provides winemakers with the most up-to- date information and advice on the management of the TDN compound in aged Riesling.
Capone, D.L. Francis, I.L. Herderich, M.J. Johnson, D.L. Managing eucalyptus aromas. Wine & Viticulture Journal 27 (4) : 22–27; 2012.
Abstract: As an investigative story, the hunt for what causes eucalyptus character – and the origin of its aroma compound 1,8-cineole – in wine has the makings of a classic ‘whodunnit’. The search for the ‘ culprit’ or ‘ally’, depending on your preference for or against eucalyptus characters, has thrown up false leads, and an unexpected ending. Studying the origin of 1,8-cineole, AWRI research found that the location and leaves of Eucalyptus trees play a direct role in the concentration of 1,8-cineole and occurrence of the ‘eucalypt’, ‘ fresh’ or ‘minty’ characters in wine.
Dambergs, R. Sparrow, A. Carew, A. Scrimgeour, N. Wilkes, E. Godden, P. Herderich, M. Johnson, D. Quality in a cool climate – maceration techniques in Pinot Noir production.Wine & Viticulture Journal 27 (3) : 18–26; 2012.
Abstract: Australia’s cool climate wines are gaining favour. At the 2011 Melbourne Wine Show a Tasmanian cool climate Shiraz won the Jimmy Watson Trophy, while in the past the Australian wine sector has built its reputation on ripe, robust, fruit-driven red wine styles. With higher production costs, cool climate viticulture can be challenging; consistent, high quality is essential for wines to be able to target higher price points in the market. This article explains how maceration techniques can influence the tannin and colour profiles of Pinot Noir, an important cool climate red wine varietal.
Godden, P. Johnson, D. Ten years of transformation: Reflecting on the technical advances in the wine industry over the past decade. Wine & Viticulture Journal 27 (2) : 24–26; 2012.
Abstract: With the current challenges faced by the Australian wine industry, it is easy to lose sight of the extraordinary technical advances that have been made in the last 10 years. Since 2002, many practices have changed markedly; from a technical perspective, there has been a transformation in how we do many things, with grapegrowers and wine producers working smarter and more efficiently. This article explores some of those changes, the science and technology behind them and the technical support necessary for that practice change to have occurred. Investments made in the AWRI and other agencies by grapegrowers and winemakers via their investment agency, the GWRDC, have been instrumental in the development of these game-changing processes.
O’Brien, V. Johnson, D. Opportunities to improve winemaking profitability. Wine & Viticulture Journal 27 (1) : 18–21; 2012.
Abstract: A team of process experts at The Australian Wine Research Institute is offering a paradigm shift for grape and wine producers competing in a crowded global market. The approach is highly practical and focussed on efficiency drawing on the team’s collective years of experience in technical winemaking and advanced manufacturing methods.