2011 Pre-vintage warning about fungal diseases-winemaking strategies
Riverina region gets a boost with regional RD&E node
New analysis methods manage stock loss through bushfire season
Spraying for downy? Check your MRLs
Locusts plaguing growers could leave residues
Concerned about VA?
International regional groups recognise the value of tannin benchmarking
Come in from the cold
Election results confirm AWRI’s Directors
Gippsland producers welcome AWRI Roadshow for first time
OIV call for papers
New books in the John Fornachon Memorial Library
2011 Pre-vintage warning about fungal diseases-winemaking strategies
Untimely spring and early summer rains have seen an outbreak of downy mildew infections in regions across south eastern Australia. In these conditions, fungal diseases such as botrytis and powdery mildew can also develop. Downy mildew damage can provide an avenue for Botrytis infection. While powdery mildew is not linked to downy mildew infection in the same way as Botrytis, it should not be ignored as it, too, can compromise wine quality.
An eBulletin released on 11 November 2010 (click here), provided an update on the downy mildew outbreak including a summary of the important issues around control. A further update was released on 6th December 2010 (click here).
In the current situation, it is important to be thinking about processing options and strategies for dealing with Botrytis infected fruit (click here) as well as managing potential issues associated with higher levels of residual elemental sulfur and copper residues from more than normal spray applications. An article outlining strategies for detailing various fungal infections can be found here. It is essential to check for laccase activity (see Commercial Services for available analyses) when dealing with fruit infected with Botrytis.
The vineyard applications used to control fungal infections may contain elemental sulfur and copper (in addition to other active constituents) depending on the type of fungal infection(s) you are trying to manage. Some agrochemical residues can have an impact during vinification.
Higher levels of residual elemental sulfur can lead to excessive hydrogen sulfide production during fermentation. For more information, refer to strategies for managing elemental sulfur (click here). Removal of elemental sulfur from red must is difficult, reduction can only be controlled through reducing application in the vineyard.
High levels of copper can also accumulate through spray applications in wet years, however it is our experience that these levels, although sometimes quite high (>5 mg/L) will decrease considerably during fermentation and be removed with the lees. It is important that copper additions post-fermentation are informed additions, that is, the concentration of copper is known before performing any copper sulfate additions.
Further assistance
Further information can be accessed through the AWRI’s Information Services team by ordering from the reference list included in the 2011 Pre-vintage warning about fungal diseases – winemaking strategies eBulletin.
Should you require further assistance, please call the AWRI’s Winemaking and Extension Services team on 08 8313 6600 or by email
Riverina region gets a boost with regional RD&E node
Following on from the successful establishment of an AWRI node in Hobart in 2008, the AWRI has now established, together with the NWGIC, a node in the Riverina.
Improved technology adoption in the NSW/Riverina area with emphasis on sustainability and environmental management is the focus of the work of the AWRI’s Dr Richard Muhlack. Established on 1 November 2010, the node, managed by Richard Muhlack, is located at the Riverina TAFE. Key deliverables from the node are expected to be:
- improved industry access to process engineering and environmental-impact reduction expertise;
- strategies and technologies which reduce costs and maximise sustainability; and
- specific demonstration of benefits of the application of process engineering and environmental impact minimisation principles.
In-depth discussions already held with the three leading wine producers in the Riverina, indicate a strong prima-facie case that large reductions in grid-supplied electricity use are possible. These producers have informed us that electricity prices in the region are forecast to increase by as much as 80% in the next five years. The node plans to work in collaboration with Charles Sturt University/National Wine and Grape Industry Centre and the University of Adelaide to develop a project addressing industry needs. The project will aim to provide definitive data which will aid Riverina wine producers to make informed business decisions. However, while focusing on the unique combinations of potential alternative energy sources which have been found to exist in the Riverina, the project will also provide data and a model which will be of great value to other wine producers seeking to conduct similar studies in their own region.
New analysis methods manage stock loss through bushfire season
For grapegrowers and winemakers, the bushfire season brings many challenges. Understanding the impacts of smoke on grapes and wine is key to minimising quality impairment and stock loss.
The negative impact of smoke from bushfires on grapes and wine has unfortunately been experienced by many Australian producers in recent years. Recent research at the AWRI on samples of grapes and wine affected by bushfires has resulted in greatly improved methods for determining the extent to which grapes are affected by smoke exposure.
Several important volatile phenol compounds have been identified in smoke and are indicative of smoke exposure in grapes and wine. All of these compounds are now measured together in the one analysis to give grapegrowers and winemakers an improved understanding of the smoke effect at the time of analysis of the fruit or wine. Find out more here
A ground-breaking outcome from smoke research has revealed that the grape rapidly transforms volatile smoke compounds into non-volatile compounds by binding to sugars within the grape. These smoke derived precursors are quite stable (not volatile) in the grape and represent another useful diagnostic marker or tool for indicating the extent of smoke exposure by the fruit.
These ‘smoke precursor compounds’ can be released as volatile smoke taint compounds during fermentation as well as over time in bottle. In this way, the smoke precursor compounds can act as a hidden storage form of undesirable smoke-affect volatiles that can become more apparent during winemaking and/or storage. Find out more about the method in Hayasaka, Y., Baldock, G.A., Parker, M., Pardon, K.H., Black, C.A., Herderich, M.J., and Jeffery, D.W. (2010) Glycosylation of Smoke-Derived Volatile Phenols in Grapes as a Consequence of Grapevine Exposure to Bushfire Smoke. Journal of Agricultural and Food Chemistry, 58(20): 1098910998, available for request here
And, don’t be fooled into thinking you don’t have a problem if you can’t smell smoke taint in your wine. Recent sensory studies on some synthesised precursors revealed that while no aroma is perceived from smelling these compounds, tasting the compounds releases the respective volatile compounds in the mouth, giving a ‘back palate’ retronasal perception of some smoke-related characters. So, whilst not imparting an aroma to wine, these compounds may be important in the perception of smoke taint. Find out more here
If you think your grapes and wine have been affected by bushfire smoke, what should you do? Both the new multi-smoke taint compounds method and the smoke precursor method above will be available from the AWRI Commercial Services in 2011. These diagnostic tools should assist grapegrowers and winemakers to make objective decisions in the event of a bushfire, or drifting smoke from prescribed burns. Contact the AWRI’s Winemaking Services for more information.
Spraying for downy? Check your MRLs
With downy mildew warnings being issued in many areas, numerous or late applications of agrochemicals may have been used to address the problem. Don’t be caught out exceeding MRLs.
The new multi-residue assay by LC/MS/MS covers a broad range of fungicides and insecticides, including most of those pesticides listed for use against downy mildew. These include azoxystrobin (Amistar), benalaxyl (Galben), dimethomorph (Acrobat), oxadixyl, trifloxystrobin (Flint), pyraclostrobin (Cabrio), captan and metalaxyl (Ridomil, Axiom). Analysis of fruit prior to harvest or processing (weighbridge samples) can alert winemakers and viticulturists to the risk of maximum residue limits (MRLs) breaches for export markets. The analysis can be performed on grapes, juice and wine and, combined with improved turnaround times, provides wineries with the ability to isolate potentially problematic batches of fruit and wine until analytical results are available.
The analysis of wine, juice and grapes is also available for other registered pesticides for use on downy mildew, such as copper, phosphorous acid and dithiocarbamates (mancozeb, metiram, zineb).
For more information regarding analysis, please contact Randell Taylor (Randell.Taylor@awri.com.au; Ph: [08] 8313 6618) or for assistance with sample submission please contact the Commercial Services Customer Service group (commercialservices@awri.com.au, Ph: [08] 8313 6600)
For more information regarding the analysis and standard pricing, see our website
Special vintage discounted prices
Grapes
10 or more sample: $175/sample
Wine/Juice
10 ore more samples: $145/sample
Please call or email Randell Taylor to discuss discounts for large sample numbers or specific requirements.
Locusts plaguing growers could leave residues
Locust plagues loom as a major threat in many warmer areas of south-east Australia over the spring and summer. Many of the insecticides permitted for use on locusts have very low maximum residue limits (MRLs) in major export countries, with some even stating ‘no detectable residues’.
The new multi-residue assay by LC/MS/MS covers a broad range of fungicides and insecticides, including all of those pesticides listed for use against locusts. These include fenitrothion, chlorpyrifos (Lorsban, Strike-Out), carbaryl (Bugmaster), diazinon and malathion (Maldison). Analysis of fruit prior to harvest or processing (weighbridge samples) can alert winemakers and viticulturists to the risk of maximum residue limits (MRLs) breaches for export markets. The analysis can be performed on grapes, juice and wine and, combined with improved turnaround times, provides wineries with the ability to isolate potentially problematic batches of fruit and wine until analytical results are available.
For more information regarding analysis, please contact Randell Taylor (Randell.Taylor@awri.com.au; Ph: [08] 8313 6618) or for assistance with sample submission please contact the Commercial Services Customer Service group (commercialservices@awri.com.au, Ph: [08] 8313 6600)
See the website for more information and standard pricing.
Special vintage discounted prices
Grapes
10 or more samples: $175/sample
Wine/Juice
10 ore more samples: $145/sample
Please call or email Randell Taylor to discuss discounts for large sample numbers or specific requirements.
Concerned about VA?
Volatile acidity production during winemaking is influenced by several factors, including juice composition and bacterial spoilage, but is strongly influenced by the metabolism of yeast strains. Some strains make more VA, some make less. Rather than dealing with a VA problem after it has occurred, a new yeast strain has been developed that may help avoid the problem altogether. A robust winemaking strain (Maurivin PDM) that produces moderate to low amounts of VA during fermentation was further improved using standard non-GE (genetic engineering) techniques. The new strain, AWRI-2051 produces 50-90% less VA, while its original fermentation characteristics were retained. For further information about the strain please contact Dr Chris Curtin and to obtain a culture for trial during the 2011 vintage contact the AWRI Culture Collection Manager Dr Eveline Bartowsky.
International regional groups recognise the value of tannin benchmarking
A number of international groups, including wineries and laboratories in Hawke’s Bay (New Zealand) and Tuscany (Italy) are realising the value of benchmarking the tannin levels in their red wines through the AWRI Tannin Portal. Although primarily set up to service individual wineries, the Portal can be used by regional organisations whose members have limited access to the necessary UV-Vis spectrometer equipment.
Tannin plays a significant role in the development of colour, texture, and aroma in red wines. Tannin and phenolic compounds contribute positively to the sensory properties and mouth-feel of red wines and have been shown to influence consumer preference and perceived wine quality.
Wineries that have subscribed since the tool was launched in July 2010 are actively assessing the tannin levels of their wines and benchmarking them against others in the AWRI’s extensive database. The Portal is used to measure levels of tannins, phenolics and pigments in wines and can be used to assess vintage to vintage variability as well as differences related to region.
Wineries using the Portal have an improved understanding of how the value and premium positioning of their wines can be improved, which can drive growth in export markets.
Most wineries that have subscribed are expected to use the tool for monitoring the development of tannin and colour in red wine ferments during the upcoming 2011 vintage. Measurements can be made in real-time, with results available within an hour of sample preparation.
Measuring tannin concentration in wine and grape juice enables wineries to manage and understand better phenolic extraction during ferments and compare the effects of different winemaking treatments. This allows the winemaker to tailor the treatment process to achieve the desired level of tannins in the resultant wines.
Enquiries and subscriptions from regions and individual wineries are invited for the upcoming 2011 vintage. For further information, please refer to the AWRI website or contact Neil Scrimgeour.
Come in from the cold
Ever wondered how electrodialysis stacks up against traditional cold stabilising techniques? The AWRI’s Commercial Services recently undertook a benchmarking exercise with interesting results.
The AWRI’s Commercial Services team is passionate about facilitating the uptake of new technologies which might provide a benefit to the wine industry. The team was recently provided with the opportunity to benchmark electrodialysis (ED) against the traditional cold stabilisation technique.
As the world becomes more environmentally conscious we need to embrace practices which reduce our environmental footprint. Traditional cold stabilisation could be responsible for up to 20% of the electricity used in a winery.
It’s time we reconsidered wine stabilisation.
The AWRI recently completed a thorough environmental and economic comparison of ED and conventional cold treatment for wine tartrate stabilisation. Under strictly controlled conditions, the two techniques were assessed with a focus on environmental footprint, economic performance, final wine quality and ease of implementation. In summary, the results indicated compelling advantages for ED, dismissing some of the previous misconceptions associated with the technology. Specifically, we identified the following:
- Power usage for ED was a very small fraction of the total used in conventional cold stabilisation (2.6% to 4.4%, depending on the agreed point where stability meets specification).
- Wine volume lost in ED was almost 1% lower than conventional cold stabilisation (0.47% compared to 1.46%).
- The ED-treated wine was stabilised inline at ambient temperature in 17 hours compared with 384 hours for cold stabilisation.
- While total water use for ED was higher (26.4 litres water per 100 litres wine compared to 12.4 litres for cold stabilisation), the waste load on the treatment system, measured as total potassium, was lower – (5.2 kg vs. 7.0 kg).
- Labour input for ED was higher (17 hours compared with 9 for cold), although the ED labour requirement was increased by the coincidence of the trial with a quarterly equipment maintenance cycle.
- A trained sensory panel could find no statistically significant difference between the two treatments.
The results of the trial show that ED appears to offer a viable alternative method to tartrate stabilisation in wine. There are clear opportunities to realise improved environmental performance, particularly in reduced electricity consumption.
Download the report in full here.
Election results confirm AWRI’s Directors
Nominations for the three vacant positions on the AWRI board were called from Australian grape and wine producers in August. With more nominations received than vacant positions in the small wine producer category, an election process was conducted in November. At its December meeting, the AWRI board confirmed the three incoming directors are Brett McKinnon (Orlando Wines), Louisa Rose (The Yalumba Wine Company) and Peter Dawson (Peter Dawson Consulting).
The election is carried out by the Australian government Department of Agriculture, Fisheries and Forestry the department responsible for the collection of levy monies from grape and wine producers. The AWRI’s Managing Director, Dr Sakkie Pretorius, said that “the department advised us that the election result was very close between the candidates for the ‘small producer’ category. It is very encouraging to see the high level of interest from industry to contribute to the AWRI.” He welcomed the reappointment of Brett McKinnon and Peter Dawson and the new appointment of Louisa Rose saying, “These are three high calibre industry members with vast experience in production and the wine business. The AWRI will benefit greatly from their contribution, which in turn will be of immense benefit to the Australian grape and wine industry.”
The AWRI’s board directors are appointed for a three-year term and can offer themselves for re-nomination at the conclusion of this term. The next round of nominations will take place in the second half of 2011 when the term of appointment for another three directors will be due for renewal.
Gippsland producers welcome AWRI Roadshow for first time
Our first Roadshow visit in the Gippsland region was held at the Century Inn, Traralgon, on 16 November.
Producers received presentations on a list of topics ranging from viticulture, latest advances in wine chemistry and new technologies. Pictured here (L to R) are Peter Godden, AWRI’s Group Manager Industry Applications, Alastair Butt of Lightfoot and Sons and Tambo Wines, Alan Bell of Mardon Hills Wine and President of Wines of Gippsland and Peter Dry, AWRI’s Viticulture Consultant.
OIV call for papers
Interested to present a paper or poster at the next OIV World Congress in Portugal?
The next OIV World Congress is being held in Porto, Portugal on 20 27 June 2011. The conference theme is The construction of wine – a conspiracy of knowledge and art. The sub-themes are as follows: construction of a wine; constructions for wine; construction of the cities of wine; and construction of wine markets. The call for papers and posters for this Congress has commenced. Submissions must be made on-line through the Congress website. First, you must register through login and password and then you can access to the submission form. Using your login and password you can always access to your submitted papers. Submissions must be received by 15 February 2011. For all further information, please visit the Congress website.
New books in the John Fornachon Memorial Library
We have had a very positive response to these titles, which are published in the Woodhead Publishing Series in Food Science, Technology and Nutrition. For a detailed description of these titles and lists of contents click on the URLs. To borrow books from the library or to order electronic copies of the book chapters, please contact the Library.
Reynolds, A. Managing wine quality: Viticulture and wine quality (Volume 1) 624 p. 2010.
http://www.woodheadpublishing.com/en/book.aspx?bookID=1521
Reynolds, A.G. Managing wine quality : Oenology and wine quality (Volume 2) xxvi, 651 p. 2010.
http://www.woodheadpublishing.com/en/book.aspx?bookID=2050
Butzke, C. Winemaking problems solved. xxiii, 398 p. 2010.
http://www.woodheadpublishing.com/en/book.aspx?bookID=1518
de W. Blackburn, C. Food spoilage microorganisms. xxiii, 712 p. 2006.
http://www.woodheadpublishing.com/en/book.aspx?bookID=835
Skibsted, L.H.; Risbo, J.; Andersen, M.L. Chemical deterioration and physical instability of food and beverages. 2010.
http://www.woodheadpublishing.com/en/book.aspx?bookID=1524
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.