Challenges with botrytis, laccase and glucans – thanks to a wet harvest
Is that wine yeast up to the task? Choosing the right strain for difficult juices
Your say is important to us
Want to know how transport and harvesting affects tropical aromas in your Savvy?
Hunter Valley and Adelaide Hills – were on our way!
A positive link between wine and improved cognitive function?
Reduced costs of export approval have been well received by many
Jancis Robinson leads international wine delegation to Tasmania
AWRI contributes to new textbook
Recent publications from AWRI staff members
If you are dealing with botrytis this vintage, you are not alone. This last month, 1 in 5 calls to our winemaking team have been about botrytis, as winemakers use all their skills this vintage to deal with the effects of processing botrytis affected fruit.
Wines made from grapes affected by Botrytis cinerea may contain laccase, an enzyme which, due to its relative stability in wine, is capable of causing serious oxidative damage. Winemaking strategies for treating botrytis infected fruit in the winery can be found here in our recent eBulletin.
AAlso be aware that botrytis can also produce and release glucans into juice and the resultant wine. Glucans are polysaccharides which are large molecules that can make the wine more difficult to filter. You can test for glucans using the polysaccharides test available on the AWRI website. Commercially available glucanases are available to break down these glucans.
Due to seasonal variation, vineyard management and differences in grape processing, grape juice composition can vary to the extent that not all yeast strains are capable of thriving in it to make quality wine. Until recently the degree to which grape juice nutrient composition could vary and how that variation affects fermentation performance was not well understood.
Recent work at the AWRI has begun to shed light on these dynamics through a survey of 100 different Chardonnay musts to determine composition and how this composition impacts on performance for different strains of wine yeast. The predominant factor limiting fermentation performance, after YAN, was juice pH. For some yeast strains low juice pH (less than 3.1) and associated low potassium levels can lead to prolonged (sub optimal) fermentation times, high residual sugar and elevated volatile acidity. This work has shown that winemakers working with low pH juices should consider insuring against fermentation difficulties and adverse quality outcomes through judicious choice of yeast strain.
You can access the paper describing the work via the AWRI library:
Schmidt SA, Dillon S, Kolouchova R, Henschke PA, Chambers PJ (2011) Impacts of variations in elemental nutrient concentration of Chardonnay musts on Saccharomyces cerevisiae fermentation kinetics and wine composition. Appl Microbiol Biotechnol DOI: 10.1007/s00253-011-3197-3
Should you require further assistance, please call the AWRI’s Winemaking and Extension Services team on 08 8313 6600 or contact us by email.
Recently, youve been given the opportunity to complete some surveys. As the industrys own innovation company, we work for you and what you have to say helps us to deliver to you more of what you really need regardless of your production size. Grape producers have been telling us about their pest and disease management strategies this season; wine industry members have been telling us what they want in our publication, Technical Review, and weve just asked wine producers to tell us about how they use water and wastewater in the production process. Improving your reality matters to us make sure you have your say.
Pest and disease management: Over 160 growers have logged onto http://www.surveymonkey.com/s/2010_11Review and shared their experiences of the 2010/2011 growing season. The information collected about pest and disease management in difficult conditions is going to help regions identify what needs to be done to manage similar conditions in the future. All growers who support their region and complete the survey will be sent the collated results. The survey will be closed on 13 May and personal information is kept confidential. For more information contact Marcel Essling on 08 8313 0370.
Winery wastewater: CSIRO and the AWRI are investigating technologies that may help wineries to improve their business sustainability through improved management of water and wastewater. The first part of our project is to gain a good understanding of how wineries use water and how they manage wastewater. The project is intended to help identify technologies worthy of trials and detailed economic investigations. Click on this link to be taken to the survey: http://www.surveymonkey.com/s/winery_wastewater. For more information contact Karl Forsyth.
Technical Review: So far, weve received comments from over 150 people regarding what they want from Technical Review in the future. Click on this link to access the survey: http://www.surveymonkey.com/s/TR_reader_survey. For more information contact Rae Blair.
The effects of transport and processing on the compounds which form the tropical aromas in Sauvignon Blanc havent been well understood. Recent studies at the AWRI have revealed some interesting facts.
This study was carried out on a commercial-scale (2.5 tonne replicates) to have direct relevance to the wine industry. One of the most important findings was that a large increase in precursor concentrations was found after transportation of machine-harvested berries. This has implications for the varietal aroma profiles of wines exhibiting tropical and citrus characters.
In this same investigation, replicated experiments were carried out to ascertain the effects of different antioxidant treatments, among other aspects. Learn more about these findings from a scientific paper that has just been published; contact the AWRI library to request a copy.
Effects of Transporting and Processing Sauvignon blanc Grapes on 3-Mercaptohexan-1-ol Precursor Concentrations. J. Agric. Food Chem. 2011, 59 (9), 46594667 .Capone, D.L. and Jeffery, D.W.
For further information, contact Dimitra Capone tel. 08 8313 6689.
Our Roadshow team are on their way to the Hunter Valley (18 May) and Langhorne Creek (25 May). Our presentations will address the technical production needs of each region.
The Australian Wine Research Institute will hold two seminars this month to address the issues faced by winegrape producers in the Hunter Valley and Adelaide Hills.
Producers in the Hunter Valley can attend the AWRI presentation on 18 May and those in Langhorne Creek can attend on 25 May.
The seminars are being held in response to a call for more information on how to deal with particular problems on behalf of the local associations in each region.
Amongst the presentations, AWRI Group Manager, Industry Development and Support Con Simos will present at both seminars, focusing on the options available in cold stabilising wine in the Hunter Valley, and management strategies for botrytis and downy mildew in Langhorne Creek.
He says the seminars provide a good opportunity to winemakers and grapegrowers to have their questions answered.
“The regional associations are given the opportunity to say ‘these are the issues and this is what we’d like you to talk about’,” Simos said. “And that’s what we do. It also gives us a great opportunity to interact with local members.”
Those who attend the seminars will also be given an opportunity to discuss other issues not covered in the presentations with the speakers for about one hour.
Grapegrowers, winemakers, suppliers and stakeholders are all encouraged to attend the event in their region.
Both seminars will feature presentations by AWRI viticultural consultant Peter Dry on how vine balance affects yield and quality as well as new AWRI technologies and consumer preferences.
Specific topics to be covered in the Hunter Valley include wine flavour, clones and wild ferments, while the Langhorne Creek seminar will focus on irrigation strategies, disease, health, eucalyptol and bunch rot.
The Hunter Valley seminar will take place from 9am-4pm on Wednesday 18 May at Mercure Resort Hunter Valley Gardens, Chardonnay Room. Cost is $65. Registration is due Monday 9 May.
Contact Melissa Romeyn from Hunter Valley Wine Industry Association on ph. (02) 4991 4533 or at email@example.com for more information.
The Langhorne Creek seminar will take place from 9am-4pm on Wednesday 25 May at Langhorne Creek Bowling Club, Sports Oval, Murray Road, Langhorne Creek. Cost is $20. Registration is due Friday 20 May.
Contact Lian Jaensch from Langhorne Creek Grape and Wine Inc. on tel. (08) 8537 3362 or at firstname.lastname@example.org for more information.
The AWRI continues its role in coordinating or participating in studies showing the impact of wine consumption on human health. A small pilot study is underway between the AWRI and the Brain Sciences Institute of Swinburne University.
This study is funded by the National Wine Foundation and focuses on whether wine-derived resveratrol has an effect on improving cognitive function (that is, the ability to think, remember and problem solve) and changes in brain blood flow in ageing or older Australians. Dementia is a form of cognitive dysfunction whereby an individual loses the capacity to think, remember and reason due to physical changes in the brain. Dementia is associated with increased disability and an increased need for institutionalised care, especially in an ageing population over 60 years of age. While there are other risk factors for dementia, ageing is by far the most important risk factor. Globally, the population aged 60 years of age is projected to triple by 2050, while the population aged over 80 years is projected to increased by five-fold. At present, there are few options for the treatment of dementia. Interestingly, older Australians generally drink less alcohol at any one drinking session than younger Australians, but they tend to drink alcohol every day. For further information on this study, contact Creina Stockley.
“Its heartening to see that AWRI is aware of the hardships faced by Australian Wine Exporters and actually doing something about it.”
Joe Ceravolo – Ceravolo Wines
The AWRI Commercial Services has been working hard over the last 18 months to streamline analytical workflows to do what we can to help the Australian wine industry. Our goal has been to reduce costs and turn around times, while maintaining our strict quality assurance regimes. We are now offering substantially cheaper analyses particularly for export certification testing (less than half price for some tests). See the AWRI website for further information.
Interested in hearing the latest developments on cool climate viticulture, oenology and marketing? Like to hear about a major three year research program into improving cool climate Pinot Noir and sparkling wines? Keen to catch up with industry colleagues from around the world?
If so, make sure you have the 8th International Cool Climate Symposium in your diary. Co-presented by Wine Tasmania, The Australian Wine Research Institute and Tasmania Institute of Agricultural Research, this event will be held in Hobart, 31 January to 4 February 2012. Click here for more information.
A new three volume text book entitled Handbook of enology Principles, practices and recent innovations, has been published recently by AsiaTech Publishers. It features two chapters by AWRI staff members: Creina Stockley and Eveline Bartowsky.
Creina’s 63 page chapter outlines the potential therapeutic effects of wine in moderation and discusses the viticultural and winemaking practices that influence the alcohol and phenolic content of wine – the two key therapeutic components of wine. Eveline’s 38 page chapter focuses on malolactic fermentation.
Research articles and books can be requested from the John Fornachon Memorial Library at email@example.com or phone us on (08) 8303 6600.
Bartowsky, E. (2011) Malolactic Fermentation. In Joshi, V.K. (ed) Handbook of Enology: Principles, Practices and Recent Innovations, Volume 2: Principles and Practices: Asiatech Publishers, Inc; New Delhi : 526-563.
Bindon, K.A., Kennedy, J.A. Ripening-Induced Changes in Grape Skin Proanthocyanidins Modify Their Interaction with Cell Walls. Journal of Agricultural and Food Chemistry 59 : 2696-2707; 2011.
Capone, D.L., Jeffery, D.W. Effects of Transporting and Processing Sauvignon blanc Grapes on 3-Mercaptohexan-1-ol Precursor Concentrations. Journal of Agricultural and Food Chemistry doi: 10.1021/jf200119z
Capone, D.L., Sefton, M.A., Jeffery, D.W. Application of a Modified Method for 3-Mercaptohexan-1-ol Determination To Investigate the Relationship between Free Thiol and Related Conjugates in Grape Juice and Wine. Journal of Agricultural and Food Chemistry doi: 10.1021/jf200116q
Cozzolino, D., Cynkar, W., Dambergs, R., Smith, P. Two-dimensional correlation analysis of the effect of temperature on the fingerprint of wines analysed by mass spectrometry electronic nose. Sensors and Actuators B 145 : 628634; 2010.
Curtin, C.D., Bellon, J.R., Bartowsky, E.J., Henschke, P.A., Chambers, P.J., Herderich, M.J., Pretorius, I.S. Harnessing AWRI’s yeast and bacteria research to shape ‘next gen’ Chardonnary Part 1: ‘Wild’ and ‘non-conventional’ yeast. Wine & Viticulture Journal January/February : 15-20; 2011.
Evans, D.E., Goldsmith, M., Dambergs, R., Nischwitz, R. A Comprehensive Revaluation of Small-Scale Congress Mash Protocol Parameters for Determining Extract and Fermentability. Journal of the American Society of Brewing Chemists 69(1) : 13-27; 2011.
Marangon, M., Lucchetta, M., Waters, E.J. Protein stabilisation of white wines using zirconium dioxide enclosed in a metallic cage. Australian Journal of Grape and Wine Research 17 : 2835; 2011.
Stockley, C. (2011) Therapeutic Value of Wine: A Clinical and Scientific Perspective. In Joshi, V.K. (ed) Handbook of Enology: Principles, Practices and Recent Innovations, Volume 1: Introduction to Vine and Wine: Asiatech Publishers, Inc; New Delhi : 146-208.
Torrea, D., Varela, C., Ugliano, M., Ancin-Azpilicueta, C., Francis, I.L., Henschke, P.A. Comparison of inorganic and organic nitrogen supplementation of grape juice Effect on volatile composition and aroma profile of a Chardonnay wine fermented with Saccharomyces cerevisiae yeast. Food Chemistry 127 : 1072-1083; 2011.
Ugliano, M., Kwiatkowski, M., Vidal, S., Capone, D.L., Siebert, T., Dieval, J., Aagaard, O., Waters, E.J. Evolution of 3-Mercaptohexanol, Hydrogen Sulfide, and Methyl Mercaptan during Bottle Storage of Sauvignon blanc Wines. Effect of Glutathione, Copper, Oxygen Exposure, and Closure-Derived Oxygen. Journal of Agricultural and Food Chemistry 59 : 2564-2572; 2011.
Varela, C., Chambers, P.J., Coulter, A., Dry, P.R., Francis, I.L., Gawel, R., Muhlack, R., Henschke, P.A., Stockley, C., Herderich, M.J., Pretorius, I.S. Controlling the Highs and Lows of Alcohol in Wine. Practical Winery and Vineyard Winter : 6-18.
Vincenzi, S., Marangon, M., Tolin, S., Curioni, A. Protein evolution during the early stages of white winemaking and its relations with wine stability. Australian Journal of Grape and Wine Research 17 : 20-27; 2011.
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.