The highs and lows of wine alcohol and mouth-feel
60 years supporting Australian wine
60th birthday wine now in barrel
Changes to Food Standards Code
16th AWITC & Trade Exhibition in Adelaide in July 2016
Order the latest AWRI staff publications online
Fining time
With vintage finishing early for many, a number of winemakers are now saying that 2015 is their best vintage for some time. Wines are now being clarified, blended, fined and stabilised and it won’t be too long before white wines go into bottle. If your wines do need a light fining, check out the AWRI’s wine fining FAQ, which details the fining agents suitable for different purposes, typical addition rates and preparation tips for both lab trials and in the cellar. If you have further questions about fining, please contact the AWRI helpdesk on 08 8313 6600 or helpdesk@awri.com.au.
The highs and lows of wine alcohol and mouth-feel
Alcohol content of red wine has an impact on mouth-feel and now researchers are closer to understanding why. Lower alcohol wines are perceived as more puckering than higher alcohol wines even when they have the same amount of tannin. New research has shown that this may be because alcohol can prevent wine tannins from binding strongly to saliva proteins.
Astringency mostly involves wine tannins binding to proteins in saliva. Wine tannins are complex molecules that have both hydrophilic (water-loving) and hydrophobic (water-fearing) parts, both of which can stick to proteins. The recent study, which was conducted with the University of Queensland, showed that tannins in lower alcohol (10%) model wines grip more tightly to salivary proteins than those in higher alcohol (15%) model wines. In higher alcohol wines the alcohol can prevent the hydrophobic parts of the tannin from sticking to proteins, leaving only the hydrophilic parts to do the heavy lifting. In low alcohol wines, both parts of the tannins can stick to proteins, enabling the tannins to bind more tightly. This may be something to consider when producing lower alcohol wines.
The full paper detailing these results is accessible via the AWRI library:
McRae, J.M.; Ziora, Z.M.; Kassara, S.; Cooper, M.A.; Smith, P.A. Ethanol concentration influences the mechanisms of wine tannin interactions with poly(L-proline) in model wine. J. Agric. Food Chem. 2015, doi: 10.1021/acs.jafc.5b00758
60 years supporting Australian wine
On 27 April 2015 the AWRI celebrated its 60th birthday – 60 years of research and technical support for the Australian wine industry. Two celebratory events were held in the birthday week – one for staff and one for past and present Councillors and Directors.
AWRI staff took part in a special session of Wine Australia’s A+ Wine School at the National Wine Centre, followed by celebratory drinks with staff from grape and wine industry bodies. Led by Aaron Brasher and Tony Love, the Wine School presented an excellent overview of Australian wine styles, from Tasmanian sparkling to Rutherglen fortifieds.
At the staff celebration, Dan Johnson gave a presentation featuring photographs and newspaper clippings from the AWRI’s 60-year history. He also announced that a new instrument for measuring metals in wine will be purchased by the AWRI to mark the 60th milestone. This instrument will provide a new capability to analyse metals and metal isotopes in wine, with applications for industry including regulatory compliance and wine provenance and authenticity investigations.
On Thursday 30 April, past and present Councillors and Directors of the AWRI attended a dinner held in the Mortlock Chamber of the State Library of SA to thank them for their contributions to the AWRI’s achievements. A very special line-up of wines was served, with vintages marking important years in the AWRI’s history. Sincere thanks are extended to all of the wineries that generously made rare museum stock available for the dinner.
‘Dog book’ update underway
The preparation of the 2015/16 edition of ‘Agrochemical registered for use in Australian viticulture’ (the ‘Dog book’) has begun. Manufacturers of agrochemicals used in viticulture are being contacted to find out about any new or discontinued products. The recommended withholding periods for grapes destined for export wines are also being carefully reviewed. Once completed, the information in the updated ‘Dog Book’ will be made available via both print and online formats.
The recommended withholding periods listed in the ‘Dog Book’ take into consideration a number of factors including:
- export market regulatory requirements such as maximum residue limits;
- good viticultural practices;
- impacts on fermentation or wine quality; and
- environmental impacts and workplace health and safety.
The recommendations are reviewed and confirmed by an Agrochemical Reference Group each year at a meeting in May. This group includes employees of organisations representing wine-grape growers, wine producers, industry associations and the AWRI. The Agrochemical Reference Group also discusses any issues related to pest and disease control that have arisen during the previous season. For more information, please contact Marcel Essling on 08 8313 6600 or marcel.essling@awri.com.au.
ERF Auction Day
Part of the Australian Government’s policy for reducing greenhouse gas emissions by 5% of 2000 levels by 2020 is the purchasing of Australian Carbon Credits (ACCUs) via the Emission Reduction Fund (ERF). ACCUs can be generated through activities that reduce greenhouse gas emissions or sequester (store) greenhouse gases when using an ERF method. For wineries and vineyards this could be based on improving energy and fuel efficiency, reducing emissions through improved soil management or undertaking a tree planting project.
The ERF enables the Australian Government to purchase lowest priced abatement on offer through a reverse auction. On 15-16 April, the Clean Energy Regulator held the first ERF auction. This auction was a success; the Clean Energy Regulator awarded 107 Carbon Abatement Contracts to the value of $660 million, to deliver a total of 47 million tonnes of abatement at an average price of $13.95 per tonne. Contracts were awarded to 43 contractors for a total of 144 projects. The majority of the contracts were awarded under sequestration methods, and landfill and alternative waste treatment methods. Contract lengths range between three and ten years, with the majority being for the standard seven years.
Detailed up-to-date information on how to participate in the ERF and the next auction can be found on the Clean Energy Regulator website. Additional resources are available on the AWRI website and at the workshops being held soon by the AWRI as part of the government’s Extension and Outreach program. These workshops will be publicised on the AWRI events calendar.
60th birthday wine now in barrel
There’s been a lot of progress in the making of the AWRI’s 60th birthday wine since the last eNews. Both primary and malolactic fermentations are complete, the wine has been blended and was recently transferred into barrels. Visit the 60th birthday wine blog for lots of photos and all the winemaking details.
Changes to Food Standards Code
Food Standards Australia New Zealand has conducted a review of the Food Standards Code to make requirements clearer and ensure it better meets the needs of stakeholders. The revised Code was gazetted on 10 April 2015 and changes take effect on 1 March 2016. The new Code can be viewed here. Resources to explain the changes, including a video are also available here. Many of the changes are related to enforcement of the code; however, one of the changes includes definitions that are used throughout the Code, which make navigation easier.For more information, please contact Creina Stockley on 08 8313 6600 or creina.stockley@awri.com.au.
Prize for thesis excellence
AWRI Health and Regulatory Manager, Dr Creina Stockley, was recently informed that her PhD thesis had been awarded the Flinders University Vice-Chancellor’s Prize for Doctoral Thesis Excellence. Creina will be presented with a medal and certificate by the Vice-Chancellor later this month. Congratulations Creina!
Roadshows on their way
The AWRI’s roadshow seminar and workshop program is entering a busy period from May to July 2015, with workshops in Mildura, Renmark, Coonawarra and Tasmania and seminars in the Hunter Valley, Langhorne Creek, Mildura, Rutherglen, Bendigo and Avoca. Visit the AWRI events calendar for dates and details of how to register for each event. For assistance, please contact the events team on 08 8313 6600 or events@awri.com.au.
What’s new in eBooks?
Six new eBooks have recently been added to the AWRI’s collection with topics including flavour chemistry, non-interventionist winemaking, terroir and phylloxera. To keep in touch with latest additions to the collection, visit the new eBook titles page on the AWRI website.
16th AWITC & Trade Exhibition in Adelaide in July 2016
The 16th Australian Wine Industry Technical Conference and Trade Exhibition is returning to Adelaide in July 2016. The program will include respected local and international speakers, workshops, technical posters, an expansive trade exhibition and networking events. A call for workshop submissions and poster abstracts will take place in the coming months and registrations will open in February 2016. Contact information and further details are available here.
Order the latest AWRI staff publications online
Accessing the latest AWRI publications is easy. Visit the AWRI Publications web page to:
- View the 10 most recent AWRI staff publications and order the articles online from the AWRI Library
- Search the staff publications database
- Read the full-text of ‘Technical Notes’ from Technical Review (PDF format)
- Read the full-text of ‘AWRI reports’ published in Wine & Viticulture Journal (PDF format).
A full list of AWRI publications published since the last eNews is included below:
1699 Curtin, C., Borneman, A., Zeppel, R., Cordente, T., Kievet, R., Chambers, P., Herderich, M., Johnson, D. Staying ahead of Brett. US Wine Business Monthly 22(3): 42, 44-47; 2015.
1700 Essling, M. Ask the AWRI: Rainfall close to harvest. Aust. N.Z. Grapegrower Winemaker (614): 32; 2015.
1701 Li, S., Crump, A.M., Grbin, P.R., Cozzolino, D., Warren, P., Hayasaka, Y., Wilkinson, K.L. Aroma potential of oak battens prepared from decommissioned oak barrels. J. Agric. Food Chem. doi: 10.1021/acs.jafc.5b00339; 2015.
1702 Mayr, C.M., Capone, D.L., Pardon, K.H., Black, K.H., Black, C.A., Pomeroy, D., Francis, I.L. Quantitative analysis of GC-MS/MS of 18 aroma compounds related to oxidative off-flavor in wines. J. Agric. Food Chem. doi: 10.1021/jf505803u; 2015.
1703 Longbottom, M. Vineyard longevity – maintaining the asset. Wine Vitic. J. 30 (2):13; 2015.
1704 Tran, T., Wilkes, E., Johnson, D. Microbiological stability of wine packaging in Australia and New Zealand. Wine Vitic. J. 30(2): 46-49; 2015.
1705 Dry, P. Tannat. Wine Vitic. J. 30(2): 61; 2015.
1706 Coulter, A. Copper: friend or foe? Aust. N.Z. Grapegrower Winemaker (615): 73; 2015.
1707 McRae, J.M., Ziora, Z.M., Kassara, S., Cooper, M.A., Smith, P.A. Ethanol concentration influences the mechanisms of wine tannin interactions with poly(L-proline) in model wine. J. Agric. Food Chem. doi: 10.1021/acs.jafc.5b00758; 2015.
Acknowledgement
The AWRI acknowledges funding from Australia’s grapegrowers and winemakers through their investment body, the Australian Grape and Wine Authority, with matching funds from the Australian Government. The AWRI is a member of the Wine Innovation Cluster in Adelaide, South Australia.