Agreement for Industry Capability Building Activities and Research and Development Program 2013-2017
Abstract
This Final report summarises all of the research, management, extension and capability enabling projects associated with AWR1306. It includes;
Research projects (also available as individual final reports):
- Project 3.1.1 Identification and origin of volatile compounds responsible for important wine sensory attributes
- Project 3.1.3 Flavour precursors: contribution to wine aroma, in-mouth sensory properties and flavour release
- Project 3.1.4 Factors affecting wine texture, taste, clarity, stability and production efficiency
- Project 3.5.3 Formation and fate of positive and negative sulfur compounds
- Project 3.3.2 Influencing wine style through management of oxygen during winemaking
Management, extension and capability enabling projects (also available as a separate, combined final report):
- Project 2.2.1 Collecting and disseminating information regarding agrochemicals registered for use and maximum residue limits in Australian viticulture
- Project 2.2.3 Informing Australia’s wine consumers through understanding issues of wine consumption, health and nutrition
- Project 2.2.4 Increasing Australia’s influence in market access, safety, regulatory and technical trade issues
- Project 3.2.5 Safeguarding and realising the potential of the Australian wine microbial germplasm collection
- Project 4.1.1 The staging and conduct of extension programs
- Project 4.1.2 Specialised technical troubleshooting and responsive helpdesk services for the Australian wine sector
- Project 4.1.3 Library service
- Project 4.1.4 Communication with stakeholders
- Project 5.1.3 Efficient management and administration
Summary
Project 3.1.1 Identification and origin of volatile compounds responsible for important wine sensory attributes
Knowledge of the flavour compounds that are responsible for the sensory characteristics of wines is of great importance to be able to control and adjust wine aroma properties in production. Compounds not previously recognised as active flavorants in specific varieties have been identified in this project for the first time, including several compounds that give Viognier wines their distinctive ‘apricot’ flavour, and a ‘green’ flavour compound in Shiraz. In addition, numerous compounds not previously understood adequately have been revealed as significant in wine flavour, such as sulfur compounds in Chardonnay being found to confer fruit attributes. Ways of adjusting the contribution of various compounds have also been examined. For example, absorption onto food grade plastic film was shown to be effective in removing ‘green’ character from a red ferment, while avoidance of material from specific wind-break vegetation planted near vineyards reduced ‘green’ flavour in wine. Another outcome of this research has been the development of analytical tools for measurement of key wine flavour compounds, and improved understanding of winemakers’ concept of ‘green’ tannin and flavour with reference to consumer preferences. Studies of Chinese consumer red wine preferences and behaviour have helped shed light on this rapidly growing and important market for Australian wine.
Project 3.1.3 Flavour precursors: contribution to wine aroma, in-mouth sensory properties and flavour release
Glycosides were previously thought to be flavourless, needing the action of enzymes during fermentation or slow chemical reactions during wine ageing to release and express their flavour. This project has established that the presence of glycosides in wine and their concomitant breakdown during tasting can boost desirable ‘fruity’ and ‘floral’ lingering flavour attributes. As a persistent aftertaste is a hallmark of quality wines, flavour release from glycosides may be a key factor differentiating between good and excellent wines.
In this project, experiments were conducted with sensory panels tasting glycosides from white wines and parallel measurement of flavour compounds in saliva or in the mouth. The results confirmed that enzymes in the saliva act like a key to a locked door, releasing a wave of additional flavour that can be perceived over the time after swallowing, creating a positive long-lasting fruity flavour sensation.
Adding purified glycosides to a juice or wine resulted in increased flavour with no negative characteristics; it was also established that white grape skins are a readily available source for extraction of glycosides which can be used as a natural flavour boost that has potential for an easily controlled new way of enhancing a wine’s sensory properties. Finally, knowledge about the profile and/or concentrations of glycosides in grapes or a wine could be used by winemakers as a quality or style indicator.
Project 3.1.4 Factors affecting wine texture, taste, clarity, stability and production efficiency
Wine texture is considered a major product differentiator both for wine style and value in the marketplace. In addition, clarity and colour stability (absence of haze development and the retention of colour) are generally considered to be pre-requisites to market success. Achieving the optimum levels for each of these parameters is often done at significant cost using current technology and does not always ensure the wine will meet its full potential. The ability to modulate these characteristics of wine while retaining the ability to economically process the wine to ensure microbial stability and stylistic integrity is a significant challenge for the wine industry. This project focused on the key compositional drivers behind texture, bitterness, clarity, stability (protein and colour) and wine filterability and developed strategies to modulate them in a production-based environment. Specifically, it covered molecular drivers of taste and texture, ‘smart’ surfaces for efficient production, predicting haze formation, understanding and preventing wine haze, effects of filtering red wines, solids management effects on white wine style and composition, impact of winemaking methods on wine macromolecules and texture, colour development/management and a practical method to determine extractable grape colour and tannin.
Project 3.5.3 Formation and fate of positive and negative sulfur compounds
Low molecular weight sulfur compounds (LMWSCs) can contribute both positive and negative sensory attributes to wines. Positive aromas include ‘passionfruit’, ‘tropical’ and ‘blackcurrant’ and negative characters include ‘rotten egg’, ‘rubber’, ‘sewage’ and ‘canned corn’. This project focused on increasing understanding of the formation and fate of sulfur compounds responsible for these sensory attributes and applying this knowledge to develop practical strategies to manipulate and modulate LMWSCs during winemaking. A further aspect was to ensure that positive and negative compounds do not undergo any further unwanted changes in tank or bottle, once a wine has a desirable LMWSC profile.
As part of this project, new advanced analytical methods were developed to enable characterisation of the very challenging and reactive LMWSCs at part per billion (ppb) concentrations and below. Another very significant breakthrough was the identification of precursors to several key LMWSCs. The work also showed that the addition of copper significantly influenced the evolution of LMWSCs. Importantly, the effects of copper differed depending on dissolved oxygen concentration post-bottling and also as a function of the residual copper concentration. In addition, copper effects were further influenced by pH and SO2 and it was demonstrated that post-bottling formation of H2S, MeSH, DMS, and CS2 is significantly impacted by both copper additions and wine pH. Beyond copper, the project showed that the formation of LMWSCs from their precursors in wine is influenced by the presence of other metal ions that naturally occur in wine, especially when present in high concentrations. Data on factors modulating the chemical formation of LMWSCs in wine was augmented by the discovery of significant differences among wine yeast in their ability to release both positive and negative LMWSCs. Taken together, this information will help winemakers to make informed choices regarding yeast strain and winemaking conditions to suit their wine style, potentially reducing the formation of negative LMWSCs in a winery environment.
Project 3.3.2 Influencing wine style through management of oxygen during winemaking
Effective management of oxygen during winemaking can help create diverse wine styles. Oxygen exposure can be readily modulated throughout the winemaking process and a range of approaches are available to manage it. However, many of these are not based on scientific knowledge of their effects on fermentation and wine style, or are not underpinned by a clear and holistic understanding of the benefits and financial impacts across the entire wine production chain.
The aim of this project was to establish the impact of early use of oxygen at crushing or during fermentation on wine style, and on the efficiency of malolactic fermentation, using both model systems and pilot-scale fermentations. In addressing these questions this research also improved understanding of how oxygen management during processing and fermentation impacts on fermentation efficiency and fast track ageing of wine. Adoption of the outcomes from this research represent a significant opportunity for the Australian wine sector to manage oxygen exposure effectively, enhance stylistic diversity, improve fermentation efficiency and reduce costs derived from excessively reductive handling of wines.
Five pilot-scale vintage trials and numerous controlled laboratory experiments were carried out during this investment period. In parallel, several industry partners trialled the use of air additions at small, medium and large-scale wineries across the country.
The benefits of adding sizeable amounts of oxygen to red ferments include a reduction in the need for adding nitrogen supplements (a significant cost saving in itself) and prevention of low levels of sulfidic off-odours, thus bringing bright fruit characters to the forefront of the wine bouquet. In addition, softening of tannins during fermentation may reduce maturation time before bottling and make the wine available for market several months earlier.
In white winemaking, the research showed that oxygen additions can increase fermentation efficiency without having negative effects on sensory outcomes. This kinetic rather than stylistic effect could have a major impact on the efficiency of fermentation by allowing a wine to finish fermentation several days earlier than normal while maintaining style through unaltered fermentation temperatures. This is a particularly valuable outcome considering the growing need to manage fermentations in compressed vintages.
Project 2.2.1 Collecting and disseminating information regarding agrochemicals registered for use and maximum residue limits in Australian viticulture
The aim of this project was to enable grape and wine producers to manage agrochemical residue levels in wine. This was achieved by collating and providing accurate and timely information on regulatory and technical aspects of chemicals registered for use in Australian viticulture, and the maximum residue limit (MRL) requirements of those chemicals in domestic and key export markets.
Project 2.2.3 Informing Australia’s wine consumers through understanding issues of wine consumption, health and nutrition
This project was funded by Wine Australia from January 2015 to June 2017, and followed on from National Wine Foundation (NWF) projects funded between July 2013 and December 2014. The aim of this 30-month project was to generate and disseminate evidence-based and scientifically sound information regarding wine and health/nutrition to facilitate informed decision-making by the wine and associated industries, policy makers and consumers. Alcohol’s place in society is being robustly debated, particularly in Australia. That debate has the potential to lead to major changes to the wine sector’s trading environment, through increased regulation in areas such as taxation, pricing, advertising, dietary guidelines and associated public health policies and strategies. The project’s approach to inform debate and decision-making was three-fold:
- generation and provision of scientific information such as reviews, reports, critiques and briefings;
- communication to stakeholders via publication of peer-review papers and industry articles; and
- provision of submissions to government on behalf of the WFA and ABA.
Project 2.2.4 Increasing Australia’s influence in market access, safety, regulatory and technical trade issues
Maintaining market access or opening markets for Australian wine, nationally and internationally, is facilitated by managing and reducing current and potential barriers to trade. Accordingly, the Australian wine industry needs to anticipate, facilitate and influence regulation of wine composition, production, labelling and marketing. The purpose of this project was to identify and mitigate any impediments to market access. The approach taken has been two-fold:
- Provision of readily-accessible regulatory-related scientific and technical advice and assistance for the activities of key industry stakeholders; and
- Representation at national and international industry forums,
Project 3.2.5 Safeguarding and realising the potential of the Australian wine microbial germplasm collection
The AWRI wine microorganism culture collection (AWMCC) is the largest repository of wine-associated yeast and bacteria in the southern hemisphere. It provides the Australian wine industry with novel, non-commercially available yeast and bacterial winemaking strains for efficient and reliable fermentations and as a means to shape and diversify wine style. The AWMCC is also essential for capturing the value of Australia’s investment in microbial strain isolation and development, especially given the current focus on bioprospecting and generating uniquely Australian isolates. It is also fundamental to the success of Wine Australia-funded biological research projects, which depend on ready access to correctly identified strains.
The collection contains:
- more than 3,000 natural yeast isolates and laboratory-modified yeast strains for research
- a wine yeast genome deletion library of more than 1,700 strains
- a laboratory yeast genome deletion library of around 4,800 strains
- more than 1,100 bacterial strains, the majority of which are malolactic bacteria.
Project 4.1.1 The staging and conduct of extension programs
The objective of this project was to provide a multifaceted and centralised extension platform to deliver research outcomes, innovations and practical solutions to Australian grape and wine producers. Face-to-face events were delivered through the long-standing Grape and Wine Roadshow program. Roadshow seminars delivered content prepared by researchers from the AWRI, affiliated WIC partners and other organisations. Relevant content was chosen by the local regional association on each occasion, giving an indication of which topics were most relevant in their region at that time. Similar content was also delivered electronically via a webinar platform. Roadshow workshops delivered tailored practical solutions to prevailing wine sector challenges with content prepared by AWRI viticulturists and winemakers. Written extension included preparation of Technical Notes and collation of articles for the bi-monthly AWRI Technical Review, preparation of articles for AWRI eNews, Wine Australia R&D@Work and RD&E news, Ask the AWRI columns and other channels, as well as preparation of content for the AWRI website. eBulletins were also prepared when required to provide the wine sector with rapid, early warnings of emerging trends and associated recommendations, based on observations from the AWRI helpdesk.
A total of 117 Roadshow events were delivered over the four years reaching 3,132 attendees, averaging 27 attendees per event. A total of 90 webinars were delivered to 1,463 attendees, averaging 16 attendees per event. A total of 237 articles and webpages were prepared and published.
A total of 97,923 webpage views/year and 20,993 downloads of fact sheets and other packaged material were recorded for the winemaking and viticulture areas of the AWRI website since the new AWRI website structure was updated in 2014, demonstrating the wide reach of this platform.
Project 4.1.2 Specialised technical troubleshooting and responsive helpdesk services for the Australian wine sector
The AWRI helpdesk provides timely and confidential support for technical problems encountered by Australian grapegrowers and winemakers. Services include identifying the root causes of problems, and providing research-based, practical, up-to-date remediation solutions, as well as future prevention strategies. The service also ensures that Australian grapegrowers and winemakers are competitive on the world stage, by having the latest technical information readily to hand. Investigative services, including analysis of problem grapes or wine, are conducted when a problem cannot be solved through discussions with the producer.
Project 4.1.3 Library service
The AWRI helpdesk also provided an early warning system for emerging technical issues, generating information which was applied to prioritisation of research and extension activities. A number of the trends observed in helpdesk enquires during the investment period were related to extreme weather events or climate change and included issues such as earlier harvest dates, higher sugar levels and stuck fermentations, vintage compression, agrochemical issues and smoke taint.
During the investment period helpdesk staff responded to and confidentially answered 7,647 queries, and performed 860 winemaking investigations.
Project 4.1.3 Library service
The John Fornachon Memorial Library (JFML) holds the largest knowledge base of grape and wine resources in the southern hemisphere and offers specialised information services and resources to the Australian grape and wine sector. Since 2013, most of the items sourced have been in digital format and the search tools that are offered are available online at all times via the AWRI website.
The library collection comprises 87,800 items covering ‘vines to wines’ and this valuable industry-owned resource is the backbone of a suite of information services available to the Australian grape and wine sector. More than 90% of the 9,569 articles delivered by the project over the investment term were provided from the library’s own collection and the remaining requests were fulfilled via inter-library loans. Library services are used by levy payers as well as government, research organisations, students, suppliers and other participants working across the Australian wine sector.
Project 4.1.4 Communication with stakeholders
This project’s primary purpose was to deliver timely and accurate communications to Australia’s grape and wine producers in order to enhance awareness and adoption of R&D outcomes. It was designed to work closely with, and complement, the activities in Projects 4.1.1. (Extension), 4.1.2 (Helpdesk) and Project 4.3.1 (Regional nodes).
Activities in this project included production of a large range of electronic and hard-copy industry publications such as the AWRI website, Annual Report, eNews and eBulletins, Technical Review, the AWRI Report, ‘Ask the AWRI’ column, ‘Alternative varieties’ column and other trade articles. An active presence in social media, management of the AWRI’s interactions with traditional media and promotion of the AWRI webinar program were also included.
Project 5.1.3 Efficient management and administration
The AWRI’s research, development and extension activities are underpinned and enabled by leadership and essential services provided by the Corporate Services group. The group works closely with the AWRI Board to provide an appropriate mix of strategic, commercial and scientific leadership, guidance and support to all AWRI staff, and increases the efficiency of all Wine Australia investments at the AWRI by allowing operational staff to focus on their core activities with minimal administrative and commercial demands.
While predominantly supported by Wine Australia, the costs of delivering the Corporate Services function over the four-year agreement term were significantly defrayed by contributions made by the AWRI’s Commercial Services group, projects not funded by Wine Australia, or otherwise underwritten by the AWRI, which together contributed more than $3.3 million.