eNews – July 2012

AWRI in review

Transport taints

Phenolics – friend or foe?

Brilliance beyond bentonite

Leveraging Lactobacillus

The ABC of MRLs

AWRI website makeover

Out of the ordinary

AWAC alumni grows

International influence

Olympic odyssey

Recent literature

AWRI in review

As most of our industry colleagues would be aware, the AWRI receives the majority of its funding from a combination of levies collected from winemakers and grapegrowers, with matching funds from the Australian government. The body who is responsible for the prudent investment of these funds, the Grape and Wine Research and Development Corporation, has recently undertaken a formal review of the current investment agreement between the GWRDC and the AWRI. The review, which was undertaken in May, was welcomed and embraced by the AWRI and involved a large number of industry personnel. Whilst the review findings are not yet finalised, a sincere thanks goes to those industry members who contributed to the process.

Transport taints

Over the past 12 months, the AWRI’s Winemaking Services team has received an increase in the number of wines submitted with taints presumed to have occurred during transport overseas in flexitanks. Appropriate sampling of wine before and after transport will assist in identifying the culprit.

There are several reasons as to why wineries choose to transport their wine overseas in bulk. The wine is typically transported in flexible tanks (wine bladder), more commonly known as flexitanks. Occasionally, some of these wines appear to be tainted when they arrive at their destination. The taint is usually a hydrocarbon one, but can be a chloroanisole or chlorophenol taint. It might be that the flexitanks are exposed to a tainted environment and that the taint goes through the bag to taint the wine. Alternatively, the flexitank wine bladder might have previously been exposed to a taint, which it then releases into the wine during transport. Either way, it is difficult to prove the wine became tainted during transport unless the right samples are submitted for analysis.

Samples of the wine from the flexitank, once it is filled, should be taken and kept as ‘holdback’ samples. Then, once the wine arrives at the destination, further samples should be taken from the tank. In this way, if the wine appears to be tainted after unloading, the ‘holdback’ and ‘destination’ samples can be tested and the results compared.

The AWRI’s investigative team is here to help. Contact us should you require any further information or assistance.

Phenolics – friend or foe?

A new report by the AWRI contradicts widely held assumptions about phenolics in white wines – particularly their assumed effects on astringency. The collaborative research project with Orlando Wines has shed new light on the impact of phenolic compounds in white wine which may allow winemakers to better manage palate texture in their wines.

The effects of the phenolic composition, alcohol and acidity levels of white wines on their mouth-feel and bitterness were assessed by a team of researchers at the AWRI using experimental winemaking, sensory, and advanced compositional analysis. The key findings were that low pH enhanced astringency, while the presence of two major phenolics in Australian white wines either increased palate ‘oiliness’ (Grape Reaction Product [GRP]) or suppressed ‘hotness’ (caftaric acid).

The AWRI researchers made experimental wines over three vintages which clearly exhibited a range of ‘phenolic’ characters. From these wines, the researchers isolated GRP and caftaric acid. These wines and phenolic compounds were used to identify correlations with sensory ratings and explore the role played by pH and alcohol on phenolic taste and texture.

In the wines made using methods designed to alter their phenolic content (i.e. pressings, hyperoxidation, skin contact), the perception of astringency was found to be far more influenced by pH than by the total amount of phenolics. Increased skin contact led to more phenolics, as expected, but unexpectedly astringency decreased and viscosity increased, mostly due to the pH increase (caused by potassium extraction from skins). However, wines to which 30% more phenolics were added were more astringent, but overall, this significant increase in total phenolics induced a relatively small increase in astringency compared to that caused by pH. The increase in astringency resulting from adding phenolics was greater in higher pH wines, once again highlighting the importance of pH on astringency. Higher pH was also associated with higher viscosity, further emphasising the importance of pH on the perception of mouth-feel in white wines. GRP was found to increase the impression of oiliness in model wine. Palate hotness or ‘burning after taste’ is most highly associated with alcohol concentration. High phenolic levels also appeared to slightly enhance the hot palate sensation, but in a further discovery, the major phenolic in white wine, caftaric acid, actually suppressed alcohol hotness. Bitterness was generally positively associated with phenolics, although not for the two major phenolics in Australian white wines (GRP and caftaric acid). This implicates some other phenolics whose identity remains unknown in white wine.

The report detailing the research carried out is now available on the GWRDC website.

Brilliance beyond bentonite

The search for alternatives to bentonite for wine protein fining has recently produced some exciting results. The AWRI has been testing two new strategies for protein removal from juices/wines that show excellent promise to become viable tools for winemakers.

The AWRI has proven that a polysaccharide from seaweeds, carrageenan, can remove proteins from juices/wines very effectively. It was also found that juice flash pasteurisation combined with an enzymatic treatment succeeded in stabilising wines too. Following these two very different approaches, the AWRI has been able to obtain wines that did not need bentonite fining, without inducing major changes on the chemical or sensorial attributes of the wines treated.

Read the latest on the work into new solutions for preventing wine protein haze in the following publications: Australian Journal of Grape and Wine Research, 18 (2), 194-202; Grapegrower and Winemaker, 580, 71–73; Food Chemistry, DOI 10.1016/j.foodchem.2012.05.042; or contact the John Fornachon Memorial Library or Dr Matteo Marangon for more information.

Leveraging Lactobacillus

Lactobacillus species are usually associated with wine spoilage, however, this species is able to conduct malolactic fermentation (MLF) in wine. In fact, a Lactobacillus plantarum strain has recently been introduced as a commercial MLF starter culture. A recent collaboration with an Italian visiting scientist is providing information on how to use these tough bacteria to our advantage.

In order to have a better understanding of how Lactobacillus strains survive in wine, a screening of Lactobacillus strains in the AWRI Wine Microorganism Culture Collection was undertaken in collaboration with an Italian visiting scientist, Mr Alessandro Moncalvo (Università Cattolica del Sacro Cuore, Piacenza). Using high throughput screening techniques developed in the AWRI Biosciences Team, Alessandro screened over 35 Lactobacillus strains (which had been collected over many years) for their ability to grow at 18-28°C; tolerance to ethanol; SO2; and pH in defined medium. As predicted, a range of phenotypes was observed. Several strains were selected for further characterisation in a red wine for their ability to survive and complete MLF. These strains are currently being identified to species level. This study will provide an important insight into how Lactobacillus survive and proliferate in wine, and will provide a better understanding to minimise their ability to spoil wine.

The ABC of MRLs

Avoid the bite of maxing out on residue levels in your wine. The AWRI’s ‘dog book’ Agrochemicals for use in Australian viticulture 2012/2013 has just been published and is also available online.

AWRI website makeover

Have you visited the AWRI’s website before? The AWRI website has had a major overhaul and information and resources for winemakers, grapegrowers, wine exporters and consumers are now easier to find and use. It is definitely worth revisting: http://www.awri.com.au.

The AWRI website contains over 12,000 pages of information. Information is easily found through the various new sections of the website:

‘Resources for Vineyards’

Why would you visit? See information and resources on: Advice and support; Agrochemicals; Analytical Services; Viti-Note Factsheets; Library and Information Services; Seminars and Workshops.

‘Resources for Wineries’

Why would you visit? See information and resources on: Advice and support; Aroma and flavor; Consultancy Services; Frequently Asked Questions; Fermentation; Laboratory establishment and methods; Library and Information Services; Online tools and databases; Packaging; Regulatory advice and support; Seminars and workshops; Sensory assessment.

‘Resources for Exporters’

Why would you visit? See information and resources on: Advice and support; Analytical services; Library and Information Services; Seminars and workshops.

‘Resources for Consumers’

Why would you visit? See information and resources on: Advice and support; Wine and health information; Library and Information Services.

Information and resources can also be found under:

About us: containing AWRI corporate information.

Research and Development: details of the AWRI’s research program and the development of research outcomes for uptake by Australian grape and wine producers.

Industry Support and Education: details of extension activities including Roadshows, seminars, workshops; resources for winemakers; winemaking advice and problem solving; online videos; and the Advanced Wine Assessment Course.

Commercial Services: details of analytical and sensory services; process optimisation; proof of performance; environmental strategy; and packaging solutions.

Information Services: find AWRI publications such as Technical Review and the Annual Report; staff publications; eBulletins; eNews; Factsheets; Grape and Wine search portal; Library Services to levy payers; and the online image collection.

Our people and employment: details of positions vacant at the AWRI and profiles of AWRI staff.

Is there something missing on our website that you would find useful? Contact us and let us know.

Out of the ordinary

Both grapegrowers and wine producers are generally enthusiastic about new grape varieties. However, wine marketers and sommeliers tend to have a more conservative approach. In order to convince wine marketers of the merits of Alternative Varieties, a special ‘Research to Practice’ workshop was presented on 12 June at the AWRI.

The audience comprised seven marketers from small to large wine companies and representatives from Barossa, Limestone Coast and Riverland regions and Wine Australia. The workshop provided a forum for discussion of the challenges faced by wine marketers in educating consumers about new varieties. For more information contact Dr Mardi Longbottom.

AWAC alumni grows

Do you want to benchmark your wine sensory ability in a rigourous, quantifiable manner? Do you know your sensory assessment strengths and weaknesses? Or, are you keen to contribute to the wine show system as a wine judge? Another 30 industry members came closer to their goals after completing the recently-held 31st AWRI Advanced Wine Assessment Course in June. Forty hours over four days including a new wine bracket, lively and interesting discussions and structured and assessed tutored tastings were a feature. Congratulations to all those who participated and are now part of the 930 who have completed the course since it first began.

The 31st AWAC settled into its new home at the Adelaide Showgrounds, also home to the Royal Adelaide Wine Show. The quality of the discussions – thanks to the great line up of guest judges and active participants – ensured the four days of the course were not only interesting and lively but of maximum value. Check out some of the comments @The_AWRI #AWAC twitter account.

Participants were also treated to the addition of a new bracket of Moscato wines, and Con Simos was joined in leading the discussion by the AWRI’s Matt Holdstock and Geoff Cowey.

Congratulations again to Peter Lehmann Wines, who followed up receiving the ‘Wine of the 30th AWAC’ with their 2003 Peter Lehmann Margaret Semillon being awarded the ‘Wine of the 31st AWAC’. The AWRI will shortly be announcing the 31st AWAC Dux who will be offered a place as an associate judge at the Royal Adelaide Wine Show.

The next AWAC course will be held in November, which promises to be even better, with some new advancements to the course now in the pipeline.

All positions in this AWAC are currently filled so if you aren’t already registered for our ballot for future AWACs, make sure you enter your name here.

International influence

The AWRI’s Health and Regulatory Information Manager, Creina Stockley, was elected to the position of President of Commission IV – Safety and Health at the OIV (Organisation Internationale de la Vigne et du Vin) General Assembly held in Izmir, Turkey last weekend. This is a three year appointment which effectively increases Australia’s influence in the wine and health and food safety arenas, as well as maintains Australia’s membership of the OIV Bureau, the peak scientific committee of the 45 member-country OIV.

Creina has been an Australian delegate and expert to the OIV since 1999, but has been informally involved since 1991 when she commenced at The Australian Wine Research Institute. A clinical pharmacologist/toxicologist, she has been Vice-President and acting President of the Nutrition and Wine expert group (2000-2006) and is currently President of the Food Safety expert group (since 2007).

Olympic odyssey

Best wishes go to the AWRI’s Customer Services Manager Commercial Services, Matthew Cream, as he and his family prepare to fly out to London to participate in the Olympic Games. Matthew has been selected to be among the 16 trios of match officials to referee the Football.

p>After arriving in London on 19 July, Matthew will receive training and instruction prior to the first matches scheduled to start on 26 July, the day before the opening ceremony. The 16 trios of match officials will cover the 32 matches, so it is likely we’ll see Matthew officiating in two matches and perhaps another two as reserve. Matches will be held in London, Cardiff, Coventry, Manchester, Newcastle and Glasgow. Matthew has been a FIFA Assistant Referee able to officiate in international matches since 2000, with the 2005 and 2009 FIFA Confederations Cup 3rd v 4th matches being highlights. Good luck Matthew!

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 AWRI 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

Bartowsky, E., Costello, P., Francis, L., Travis, B. Oenococcus oeni and Lactobacillus plantarum : Effects of MLF on red wine aroma and chemical properties. Practical winery & vineyard 33 (2) : 57-59; 2012.

Coulter, A. Laccase and rot: Is it there or is it not? Australian & New Zealand grapegrower & winemaker (579): 69-72 ; 2012.

Cowey, G. How and why identify matter other than grapes. Australian & New Zealand grapegrower & winemaker (580): 77-78 ; 2012.

Cozzolino, D., Cynkar, W.U., Shah, N., Smith, P. Multivariate data analysis applied to spectroscopy : potential application to juice and fruit quality. Food research international 44 (7) : 1888-1895 ; 2011.

Curtin, C., Kennedy, E., Henschke, P.A. Genotype-dependent sulphite tolerance of Australian Dekkera(Brettanomyces) bruxellensis wine isolates. Letters in applied microbiology 55 (1): 56-61; 2012.

Curtin, C. D. Borneman, A. R. Henschke, P. A. Godden, P. W. Chambers, P. J. Pretorius, I. S. Advancing the frontline against Brett : AWRI breakthrough offers potential to transform the battle against Brett. Practical winery & vineyard 33 (2) : 47-48, 50-54, 60; 2012.

Curtin, C. Borneman, A. Chambers, P. Pretorius, S. Winning at snakes and ladders. Practical winery & vineyard 33 (2) : 55-56; 2012.

Dambergs, R.G., Mercurio, M.D., Kassara, S., Cozzolino, D., Smith, P.A. Rapid measurement of methyl cellulose precipitable tannins using ultraviolet spectroscopy with chemometrics: application to red wine and inter-laboratory calibration transfer. Applied spectroscopy 66 (6) : 656-664 ; 2012.

Dambergs, R., Sparrow, A., Carew, A., Scrimgeour, N., Wilkes, E., Godden, P., Herderich, M., Johnson, D. Quality in a cool climate –maceration techniques in Pinot Noir production. Wine & viticulture journal 27 (3) : 18, 20-26 ; 2012.

Henschke, P.A., Varela, C., Schmidt, S., Torrea, D., Vilanova, M., Siebert, T., Kalouchova, R., Ugliano, M., Ancin-Azpilicueta, C., Curtin, C.D., Francis, L. Modulating wine style with DAP: case studies with Albariño and Chardonnay. Australian & New Zealand grapegrower & Winemaker (581): 57-58, 60-63; 2012.

Henschke, P., Bellon, J., Curtin, C., Chambers, P. Breeding for success: yeast strain development at the AWRI. Wine & Viticulture Journal 27(3): 35-39 ; 2012.

Krömer, J.O., Nunez-Bernal, D., Averesch, N.J.H., Hampe, J., Varela, J., Varela, C. Production of aromatics in Saccharomyces cerevisiae — A feasibility study. Journal of biotechnology doi.org/10.1016/j.jbiotec.2012.04.014: 1-10 ; 2012.

Longbottom, M. Mixed cost and quality effects from thinning. Australian & New Zealand grapegrower & winemaker (579): 52 ; 2012.

Marangon, M., Lucchetta, M., Duan, D., Stockdale, V.J., Hart, A., Rogers, P.J., Waters, E.J. Protein removal from a Chardonnay juice by addition of carrageenan and pectin. Australian journal of grape and wine research 18 (2) : 194-202; 2012.

Marangon, M., Pocock, K. F., Waters, E.J. The addition of bentonite at different stages of white winemaking and its effect on protein stability. Australian & New Zealand grapegrower & winemaker (580) : 71-73; 2012.

Marangon, M., van Sluyter, S.C., Robinson, E.M.C., Muhlack, R., Holt, H., Haynes, P.A., Godden, P.W., Smith,
P.A., Waters, E.J. Degradation of white wine haze proteins by a glutamic acid peptidase during juice flash pasteurization. Food chemistry doi.org/10.1016/j.foodchem.2012.05.042: 1-42; 2012.

Pretorius, I.S., Curtin, C.D., Chambers, P.J. The winemaker’s bug : from ancient wisdom to opening new vistas with frontier yeast science. Bioengineered bugs 3 (3): 147-156; 2012.

Scarlett, N., Bindon, K. Case study of vigour-based zonal vineyard management and phenolic variation in wine Wine & Viticulture Journal 27(3): 41-43 ; 2012.

Schmidt, S.A., Jacob, S.S., Ahn, A.B., Rupasinghe, T., Krömer, J.O., Khan, A., Varela, C. Two strings to the systems biology bow: co-extracting the metabolome and proteome of yeast. Metabolomics DOI 10.1007/s11306-012-0437-1:1-16; 2012.

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.