The Australian Wine Research Institute

What’s the dirt? Hunter Valley Semillon Project: putting science into the subregions
Cool runnings
Launch of AWRI’s new workshop – Adapting to difficult vintages
Do you use refractometers to determine wine grape price? If so, these changes affect you.
Coonawarra trial highlights the power of vintage
New speakers confirmed for WINEHEALTH 2013
Introducing a new breed of wine yeast
Interact with the experts at AWITC workshops
Can you help enhance the Agrochemical App?
Grape marc – a surprise contributor to greenhouse emission reduction
Sign up for sensory sessions
Recent literature

What’s the dirt? Hunter Valley Semillon Project: putting science into the subregions

As in other premium Australian grape growing regions, Hunter Valley winemakers are increasingly focussing on producing single vineyard and subregional wines to express the unique characteristics they are seeking. Up until now, however, the belief amongst Hunter winemakers that vines grown on the four main soil types in the region produce fruit with different flavour, style and phenolic profiles hasn’t been tested either on the tasting bench or in the lab. The Hunter Semillon project, coordinated by Sam Connew at the AWRI’s Hunter node, aims to investigate whether soil type (and thus subregion) plays a significant role in the flavour profile of Semillon wines and to explore the impact of phenolics on both juice and wine characteristics.

The first stage of the project was a formal tasting of 55 single vineyard wines from 2011 and 2012, set up to investigate the descriptive terms used to describe differences between wines originating from different soil types and sub regions. These wines were also analysed for basic wine chemistry to determine any significant trends.

In the 2013 vintage, fruit samples were collected from over 20 different vineyards and the resultant juices assessed for phenolic profiles. Fruit samples from five of these vineyards were then processed identically and the resulting wines were also reviewed for phenolic profiles. Initial data collected on the juice samples using key UV-Vis wavelengths indicated that grapes grown on different soil types contained different phenolics and that hydroxycinnamates might be an important class of compounds responsible for the differences seen between the samples. The implications of this for Hunter Valley Semillon are important, as one of the characteristics of hydroxycinnamates is that they are powerful antioxidants and give white wines good ageing potential. This study has so far shown that soil type and subregional characteristics have a role to play in wine phenolic profiles.

The latest results from this project will be presented on 16 July in a workshop ‘The terroirs and tastes of Hunter Semillon’ at the 15th Australian Wine Industry Technical Conference. The workshop will include a tasting of single vineyard Hunter Semillons and will also feature a classic Hunter vs Barossa match-up of Tyrrell’s Vat 1 Semillon vs Peter Lehmann Margaret Semillon.

Cool runnings

Electricity prices are rising. As this vintage comes to an end, it’s timely to think about taking steps to reduce winery electricity costs. Perhaps by moving some electricity use to cheaper off-peak periods, by arranging a better deal on electricity from another provider, or obtaining a government subsidy to insulate tanks? Refrigeration is the major component of most winery electricity bills and therefore a good area for focus. For some general ideas on refrigeration, check out the AWRI’s short reference guide.

Launch of AWRI’s new workshop – Adapting to difficult vintages

The AWRI will launch a new workshop ‘Adapting to difficult vintages’ in the Barossa Valley on Wednesday 15 May and in the Clare Valley on Tuesday 21 May. This workshop, developed for both grapegrowers and winemakers, focuses on coping with extreme weather conditions. Topics covered include heatwaves, bushfire, drought and excessive rain.

Participants will learn about the latest adaptation techniques for a wide range of weather-related events, both in the vineyard and in the winery. Presentations will discuss strategies to deal with drought, salinity, extreme heat, bushfires, smoke taint, processing very ripe fruit and avoiding stuck fermentations. Tactics for dealing with a compressed vintage and the associated logistical pressures will also be covered, giving participants a chance to share their experiences from vintage 2013.

Information will also be provided on growing grapes and making wine in wet seasons, including dealing with floods, high disease pressures including Botrytis, the impact of laccase and effects on filtration. The workshop will explore energy use and efficiency savings in the winery, waste water management, and will include practical exercises and tastings of regionally-suited alternative variety wines. To register, or to check out future dates and locations for this workshop, visit the AWRI Events Calendar or the Grape and Wine Events Calendar.

Do you use refractometers to determine wine grape price? If so, these changes affect you.

The National Measurement Institute (NMI) is working with a number of stakeholders in the wine grape industry, including the AWRI, on changes to the rules for refractometers. The changes will ensure that those instruments used to determine the unit price of wine grapes are accurate, traceable and comply with relevant legislation. Transitional arrangements are being provided for refractometers that are currently in use by industry. Action is required before 30 June 2013.

NMI, part of the Department of Innovation, Industry, Climate Change, Science, Research and Tertiary Education, is the peak Australian measurement body responsible for biological, chemical, legal, physical and trade measurement. NMI is responsible for Australia’s units of measurement and the development and maintenance of standards of measurement, reference materials and reference techniques. NMI provides a variety of services to industry and government, including calibration, measurement, analysis and training.

As part of the new process for refractometers, instruments will need to comply with the national standard NMI M 9. With the introduction of the standard, growers and wineries can be reassured that new refractometers will undergo thorough testing, verification and approval to make certain that they are suitable for use and maintain their accuracy over time.

Under transitional arrangements, refractometers that are currently used by industry can be considered for approval on a restricted basis, known as ‘grandfathering’. This will allow existing instruments to continue to be used for trade on or after 1 January 2014. Following grandfathering, instruments will need to be verified prior to their use.

To apply for grandfathering, please submit an application by 30 June 2013 to roselle.mailvaganam@measurement.gov.au.

The application should include the following details for each type of refractometer:

• make and model
• specifications including:
  • accuracy class – digital handheld device (type III), digital bench top device (type II) and automatic refractometers capable of making continuous measurement without operator intervention (type I).
  • measurement unit
  • temperature compensation facility

For more information, please contact Ms Roselle Mailvaganam on (02) 8467 3832 or roselle.mailvaganam@measurement.gov.au.

Coonawarra trial highlights the power of vintage

A four-year trial carried out in conjunction with Wynns Coonawarra Estate has highlighted the significant impact that vintage weather conditions can have on the development of colour and tannin levels in red grapes. Average temperature during the growing season was the most significant factor in increasing the tannin levels achieved in the grapes at harvest. The trial also studied the effect of soil type and clonal differences on the phenolic profiles of Cabernet Sauvignon, but neither had a consistent impact on the accumulation of tannins or anthocyanins in the grapes across the four vintages.

This trial assessed the impact of vintage, soil type and clonal differences on the phenolic profiles of Cabernet Sauvignon grapes grown in Coonawarra from 2009 to 2012. Five Cabernet Sauvignon clones: CW44, G9V3, Reynella, LC10 and SA125, grown in one Coonawarra vineyard with two soil types (Terra Rossa and Ground Water Rendzina) formed the basis of the trial. Parcels of fruit were processed using identical winemaking techniques in order to compare the phenolic profiles of the resultant wines.

The impact of average temperatures experienced during the growing season was the most significant factor for tannin development in the grapes, with warmer vintages producing fruit with higher tannin levels and lower anthocyanin levels. Grape tannin and colour levels at harvest also had a significant influence on colour and tannin levels in the resultant wines. High colour levels in the wines were only achieved when the grapes contained comparatively high levels of anthocyanins AND tannins.

Tannin concentration at 3-4 weeks before harvest proved to be a good indicator of tannin concentration at harvest and could therefore be used to optimise picking times to achieve a desired target tannin level in the grapes. Neither clonal type nor soil type was found to have a consistent impact on the accumulation of tannins or anthocyanins in the grapes across the four vintages.

The wines produced during these four vintages were significantly different in terms of their colour and tannin concentrations, even though identical winemaking techniques were used, and this was reflected in the sensory assessment ratings assigned by Wynns. Wines produced from clone SA125 grown on Terra Rossa were consistently the most preferred from each vintage. Soil type did appear to influence wine sensory characteristics and resulting preference in some cases; clone CW44 generally performed better on Rendzina whilst clones Reynella and G9V3 performed better on Terra Rossa soil.

A detailed summary of this work will be presented in the June edition of the AWRI’s Technical Review and outcomes will be presented through a series of posters at the upcoming AWITC in Sydney. For more details, contact Neil Scrimgeour.

New speakers confirmed for WINEHEALTH 2013

Professor Ramon Estruch from the University of Barcelona and Associate Professor Leon Simons from the University of New South Wales have recently confirmed their participation in WINEHEALTH 2013. Their presentations will be two highlights of many within the program of this international conference on the complex relationship between wine consumption and health. Prof Estruch studies the effects of alcohol consumption on the human body and A/Prof Simon is the Principal Investigator of Australia’s longest running study of healthy ageing. WINEHEALTH 2013 takes place in Sydney from 18-20 July 2013, immediately following the 15th AWITC.

Prof Estruch will present in the ‘Wine and cardiovascular disease’ conference session, focusing on a recent study comparing the effects of red wine, dealcoholised red wine and gin on cardiovascular markers. A/Prof Simons will present in the conference session that covers epidemiological evidence on the relationship between alcohol consumption and human health. Other sessions will include ‘Grapes, wine and nutraceuticals (omics)’, ‘Integrated Medicine – Healthy Ageing’ and ‘Our daily diet and lifestyle – interactions with wine’. To register or for more information, please contact Kate Beames on +61 (0) 8 83136821 or visit the conference website.

Introducing a new breed of wine yeast

Question: How can we reap the benefits of complex flavours and aromas derived from spontaneous fermentations while minimising the risk of spoilage?

Answer: Breed complexity into our wine yeast!

The AWRI has generated a new breed of wine yeast by interspecific hybridisation between a robust Saccharomyces cerevisiae wine yeast strain and Saccharomyces mikatae, a species not before associated with industrial fermentation.

By using a robust S. cerevisiae wine yeast as one parent, the hybrid yeast inherit the fermentation properties necessary for industrial usage whilst delivering novel, and wider ranging, yeast-derived flavours from the S. mikatae parent.

Chardonnay wines made with the new hybrid yeast showed different concentrations of volatile compounds known to contribute to wine flavour and aroma including flavour compounds associated with non-Saccharomyces species. The new S. cerevisiae x S. mikatae hybrids therefore have the potential to produce complex wines akin to products of spontaneous fermentation while giving winemakers the safeguard of an inoculated ferment. You can find out more on this development in the June issue of Australian & New Zealand Grapegrower and Winemaker or by contacting Jenny Bellon.

Interact with the experts at AWITC workshops

The 15th AWITC is coming up fast and the workshop program is always a major highlight. There are 44 interactive workshops on offer, covering topics from winemaking, viticulture and the environment, to business, social media, wine law and regulatory information. The workshop program is your one chance to get up close and personal with experts in all of these fields. To find the workshops you just can’t miss, check out all the details in the workshop program.

Workshop places always fill fast, particularly for the most popular topics and tastings. ‘Perfecting Pinot Noir’, wine texture and environmental issues are hot topics at the moment. Register today to make sure you don’t miss your first choices.

Some of the top selling workshops include:

Can you help enhance the Agrochemical App?

The AWRI Agrochemical Search app gives growers access to ‘Dog Book’ Agrochemical information on-the-go via mobile phones or tablets. The user selects the target pest or disease and the growth stage of the vine to receive a list of recommended active constituents and products registered in Australia. Since its release in November 2012, the app has been downloaded onto over 500 devices and been used for more than 2,300 searches. It can be downloaded for free from iTunes or Google Play.

An upgrade of the app to give further assistance to growers is now underway. To make sure this upgrade is as useful as possible, feedback from current app users is essential. Please complete this very short survey and have your say about the types of functions or information that would help you make spray decisions. Thank you for helping to improve the app!

Grape marc – a surprise contributor to greenhouse emission reduction

When thinking about reducing Australia’s greenhouse gas emissions, a winery by-product might not be the first thing to come to mind. It seems, however, that the tannins contained in grape marc may have an important role to play.

Grape marc, the left over skins and seeds from the wine making process, contains tannin and lots of it. When fed, as a dietary supplement, to cattle or other ruminant animals grape marc has been shown to reduce methane emissions. This is great news as methane emissions from enteric fermentation (livestock digestion) is estimated to contribute 10% of Australia’s national greenhouse gas emissions. Also, it looks promising for cattle farmers too as the reduction in methane loss during the digestion process may be linked to an increase in liveweight gain and hence in productivity.

As one of many research organisations participating in the National Livestock Methane Program (NLMP); the AWRI is working towards characterising different types of grape marc and assessing its performance and suitability as a methane reducing feed supplement. An additional objective is to identify if there are potential risks associated with agrichemical residues within grape marc.

Over the last six months the AWRI has developed and refined analytical techniques and methods that enable tannin levels and composition to be understood and quantified in grape marc. These analytical techniques have revealed the incredible diversity of both tannin type and tannin concentration in grape marc. The next stages of the project will use digestion simulation methods to quantify the methane suppression and productivity enhancing properties of different tannin types.

The project is supported by funding from the Australian Government Department of Agriculture, Fisheries and Forestry as part of its Carbon Farming Futures Filling the Research Gap Program with management support from Meat & Livestock Australia. For more information on this project contact: Karl Forsyth or Josh Hixson.

Sign up for sensory sessions

Two Advanced Wine Assessment Courses will be held in Adelaide in October 2013. Register your details here to make sure your name goes into the ballot for course places. The AWAC is a must for aspiring wine judges and anyone in the wine sector wanting to take their tasting skills to the next level. Want to know more? Course details are here, or you can peruse a previous course program or express your interest at awac@awri.com.au or (08) 8313 6600.

Recent literature

John Fornachon Memorial Library at the AWRI delivers journal articles and loans books to Australian grapegrowers and winemakers. Books can be searched and requested via the Library catalogue – or you can email the Library with your request. A list of recent AWRI publications follows.

• To order AWRI staff publications and articles from Technical Review please contact the Library.
• Articles and books on specific topics can be searched for and ordered via the Library catalogue
• To request a Literature search on a specific topic contact the Library via email or telephone (08) 8313 6600.

Recent AWRI staff publications

Borneman, A.R., McCarthy, J.M., Chambers, P.J., Bartowsky, E.J. Comparative analysis of the Oenococcus oeni pan genome reveals genetic diversity in industrially-relevant pathways. BMC Genomics. 13: 1-13; 2012.

Capone, D.L., Francis, I.L., Herderich, M.J., Johnson, D.L. Eucalyptus aromas: a mystery. Researchers confirm source behind minty characters. Wines & vines 94 (2): 52-57; 2013.

Curtin, C., Cordente, T. Flavour-active wine yeasts: little things that have a big impact. Australian & New Zealand grapegrower & winemaker (589): 54-56; 2013.

Dry, P. Ask the AWRI: What can you tell me about controlling Botrytis bunch rot without the use of fungicides? Australian & New Zealand grapegrower & winemaker (589): p.28; 2013.

Dry, P. Sagrantino. Wine & viticulture journal 28 (2): p.53; 2013.

Dry, P. Can the production of low alcohol wines start in the vineyard? Wine & viticulture journal 28 (2): 40-43; 2013.

Gawel, R., Day, M., Schulkin, A., Smith, P., Herderich, M., Johnson, D. The science of texture. Wine & viticulture journal 28 (2): 30-34; 2013.

Disclaimer

The material contained in this publication is comment of a general nature only and is not and nor is it intended to be advice on any specific technical or professional matter. In that the effectiveness or accuracy of any technical or professional advice depends upon the particular circumstances of each case, neither the AWRI nor any individual author accepts any responsibility whatsoever for any acts or omissions resulting from reliance upon the content of any articles. Before acting on the basis of any material contained in this publication, we recommend that you consult appropriate technical/professional advisers.