The Australian Wine Research Institute

The Australian Wine Research Institute Blog

March 2010

1 March 2010 >

Stuck on sulfur?
Message in a bottle
All about salt
Tracking tropical
Green talent
London tastes Australia
New chair

Stuck on sulfur?

If you’ve sprayed your grapes with sulfur and need to harvest now within the 30 day withholding period, the AWRI has some advice to help you.

If you are concerned about the effects of sulfur on yeast and fermentation, access our eBulletin which offers easy-to-follow advice to reduce your risk of problems. Contact Marcel Essling from the AWRI’s Viticulture team on (08) 8313 6600 for more information.

Message in a bottle

Did you know that the loss of fresh fruit characters and the development of ‘reductive’ and ‘oxidised’ characters could be the result of poor management of oxygen transmission through wine bottle closures or packaging? Commercial Services can now accurately measure the oxygen transmission rate (OTR) of your packaging non-destructively.

Brand new and proven to be highly reproducible, the method directly measures the real OTR of different closures and packaging solutions while they are in contact with wine. It can be used to check ‘problem’ bottles from a particular batch or weak points in bulk container packaging. Email AWRI Commercial Services or call on (08) 8313 6600 to test your closures, or access the Commercial Services Packaging solutions webpage for more information.

All about salt

Are you confused about salt? Do you know whether to measure sodium or chloride concentration? What’s the legal limit? Is there a link between high salt levels in petioles (leaf stems) and the amount that ends up in wine?

The AWRI’s salinity experts are here to help. They recommend that you measure chloride ion concentrations to stay within legal limits. The Australian and New Zealand Food Standards Code has set the limit at 1000 mg/L of soluble chlorides expressed as sodium chlorides that equates to 607 mg/L of choride ion.

As for petioles – taken at flowering or veraison – there’s evidence that high salt levels might indicate more salt in your grape juice. How much, however, cannot be predicted.

To find out more about salt in winemaking contact Geoff Cowey.

Tracking tropical

What’s the link between tropical aromas in Sauvignon Blanc and the precursors (or compounds) that create them? How do they change or degrade in the vineyard, during transport and in winemaking?

The AWRI’s Aroma Chemistry team has been on a mission to find out. Their discoveries have just been published – a must-read for anyone wanting to know how tropical thiol aromas are created and how precursors change from the vineyard to the winery.

For a summary access the 2009 AWRI Annual Report, or contact the AWRI Library to request the scientific publications:

Synthesis of Wine Thiol Conjugates and Labeled Analogues: Fermentation of the Glutathione Conjugate of 3-Mercaptohexan-1-ol Yields the Corresponding Cysteine Conjugate and Free Thiol. J. Agric. Food Chem. 2010, 58: 13831389.

Analysis of Precursors to Wine Odorant 3-Mercaptohexan-1-ol Using HPLC-MS/MS: Resolution and Quantitation of Diastereomers of 3-S-Cysteinylhexan-1-ol and 3-S-Glutathionylhexan-1-ol. J. Agric. Food Chem. 2010, 58: 13901395.

To find out more contact Dimi Capone, or view the AWRI’s wine thiol precursors webpage.

Green talent

Are you committed to environmentally-friendly wine production, but don’t know where to start or what to do next? The AWRI Commercial Services has a new ‘green team’ of specialists ready to help you.

Karl Forsyth can help you to adopt a range of sustainable practices from more effective wastewater management to calculating your carbon footprint. In today’s environmentally-conscious marketplace, their expertise offers you a competitive edge.

For more information email Karl Forsyth.

London tastes Australia

The AWRI delivered a ‘taster’ of its Advanced Wine Assessment Course in London, in February, in conjunction with Wine Australia’s Annual Trade Tasting, World Class Australia Event.

Hosted by Con Simos, Group Manager, Industry Development and Support at the AWRI, the short course put 26 participants through their paces with two ‘flights’ of Riesling and Shiraz wines. Some wines were repeated to test tasters’ ability to score reliably and consistently.

The day presented a new approach to tasting Australian wine and a snapshot of the AWRI’s well-regarded four-day Advanced Wine Assessment Course. Con Simos went on to showcase the AWRI’s work on flavor including revealing black pepper and eucalyptus aromas as well as other AWRI research programs in Dublin, Ireland.

New Chair

The AWRI has announced that Mr Peter Dawson has been appointed Chair of the AWRI board.

Mr Dawson has played a pivotal role in the development of one of Australia’s largest wine companies Hardy’s – and the industry as a whole. He has served on many industry advisory committees, including the board of the AWRI for the past 10 years.

Peter brings his winemaking credentials as well as stable and visionary stewardship to the board.

Read the AWRI’s media release.

Elemental sulfur residues – potential impact on fermentation and management strategies

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During the current vintage, our Viticulture team have received queries regarding the impact that elemental sulfur residues might have on fermentation.

Background

For the control of Powdery Mildew, the AWRI recommends a thirty day withholding period (WHP) for grapevines which are sprayed with elemental or crystalline sulfur. Use of these chemicals within the WHP may increase the risk of residue levels remaining in must. This may lead to fermentation problems. The WHP is set to allow enough time for elemental sulfur to degrade to levels that minimise the risk of fermentation problems. Research indicates that as the length of time between the application of sulfur in the vineyard and harvest increases, the impact on fermentation declines.

Implications

Elemental sulfur residues in must can be converted by yeast to sulfurous off-flavours such as hydrogen sulfide (H2S) during fermentation. During and after fermentation, elemental sulfur may also be reduced to sulfide by enzymatic or non-enzymatic chemical processes.

The main factors that control H2S production from elemental sulfur are:

  • temperature (lower production at lower temperature);
  • oxidation potential (higher production rate at lower oxidation potential); and
  • ethanol concentration (lower production at lower ethanol concentration).

Elemental sulfur can also oxidise to sulfur dioxide (SO2) and have an antimicrobial affect on inoculated yeast, delay the onset of fermentation or cause a slow or sluggish fermentation.

Management strategies

Settling of white musts before fermentation might remove some elemental sulfur in the lees.

Treat the ferment as ‘high risk’, paying attention to temperature, oxidation and fermentation rate.

Ensure adequate YAN (yeast assimilable nitrogen) levels in juice to facilitate good yeast performance.

Use of low hydrogen sulfide producing yeast strains could limit the amount of hydrogen sulfide produced.

Addition of greater yeast inoculums as a sacrificial culture could assist with binding of elemental sulfur and generated SO2.

Please click here to download the AWRI stuck fermentation fact sheet.

Further queries

If you require further information, please contact the Winemaking and Extension services team on (08) 8303 6600

or by e-mail
Viticulture
Winemaking
Health and Regulatory

Or visit our website for more information.

February 2010

1 February 2010 >

eNews welcome
No to natamycin
Copper watch
Having filtration problems?
Tracking tannin
What’s that horrible smell?
Found an amazing fermentation?
The 14th Australian Wine Industry Technical Conference (AWITC)
Where are you now?
Congratulations Con!
Vintage papers

eNews welcome

Welcome to our first issue of the AWRI’s e-newsletter. The purpose of the newsletter is to give you quick, easy and regular updates on our activities. We hope you find this newsletter of interest and we welcome your feedback.

No to natamycin

With many export countries clamping down on the fungicide natamycin, the AWRI Commercial Services is offering screening services and support to Australian winemakers.

Natamycin is used by food manufacturers to stop the growth of yeasts and mould. Whilst it is permitted for use in winemaking in South Africa, natamycin is not permitted as a winemaking additive in Australia.

Some export countries require residues of natamycin to register below 0.005 mg/L. To make sure your wines meet this requirement AWRI Commercial Services can help you.

For more information click here or contact Randell Taylor on 08 8313 6600.

Copper watch

This month the AWRI is advising all winemakers to check copper levels in their reds and whites to stay well within international standards.

Our Health and Regulatory Manager, Creina Stockley, reminds us that Canada has a copper limit of less than 1.0 mg/L, while the USA has a limit of 0.5 mg/L.

To find out more, read our paper, below, about copper additions and other treatments for sulfide development. You can also contact the AWRI’s Geoff Cowey for advice.

Cowey, G. Excessive copper fining of wines sealed under screwcaps – identifying and treating reductive winemaking characters. Australian & New Zealand Grapegrower & Winemaker. 531 : 49-56 ; 2008.

Having filtration problems?

Could your filtration problems be caused by polysaccharides? The AWRI has a test that can help you.

Our researchers found that some 2008 and 2009 reds were harder to filter due to polysaccharides. They have uploaded a polysaccharides test now available on the AWRI website.

The test is simple to use and will help you to work out whether polysaccharides are causing your filtration problems. To access the test, you’ll need a password, available here. You can also contact the AWRI’s Geoff Cowey for more information.

Tracking tannin

The AWRI’s new tannin web portal offers fast, easy analysis of tannin, total phenolics and total pigment in red wines and ferments.

This online tool allows users to enter their own UV-Vis spectral data into a web interface to instantly receive results. The results can also be benchmarked against our extensive database. To find out more, read our Factsheet.

Interested in a sneak preview? To be part of our pilot users group click here or contact Commercial Services on 08 8313 6600.

What’s that horrible smell?

Hydrogen sulfide and mercaptans can make the best wine smell and taste of rotten egg or burnt rubber. But thanks to research at the AWRI, winemakers can now access a new service to identify and quantify many of the key compounds responsible for these so-called ‘reductive’ aromas.

Created primarily by stressed yeast cells or changes in sulfur chemistry under anoxic conditions, the ‘rogue’ compounds can have a significant sensory impact even at trace levels.

For more information click here, or contact Randell Taylor from AWRI’s Commercial Services on 08 8313 6600.

You can also access these papers from the AWRI Library:

O’Brien, V. Colby, C. Wine faults caused by reductive characters: low molecular weight sulfur compounds. Australian and New Zealand Wine Industry Journal 23 5 : 50, 52, 54-55 ; 2008.

O’Brien, V. Francis, I.L. Osidacz, P. Packaging choices affect consumer enjoyment of wines. Australian and New Zealand Wine Industry Journal 24 5 : 48-54; 2009.

Found an amazing fermentation?

If you’ve discovered an intriguing fermentation, the AWRI can help you to repeat that fermentation by isolating the related yeast or bacteria and storing it for future use.

Maybe you’ve encountered characters you’d like to access again, or you would need support with storage of your yeasts or bacteria.

Contact the AWRI Wine Microbiology Culture Collection for more information or contact Eveline Bartowsky or Jane McCarthy on 08 8313 6600.

The 14th Australian Wine Industry Technical Conference (AWITC)

Online registration opens soon for the 14th AWITC, to be held at the Adelaide Convention Centre, South Australia, 3-8 July 2010.

This year’s conference promises to be an exciting and informative event with a wide range of speakers from the grape and wine sector.
Click here to access the conference program.
Click here to access the workshop program.

For more information, visit http://www.awitc.com.au/ or contact Kate Beames on 08 8313 6696 or at info@awitc.com.au

Where are you now?

If you’ve attended an AWRI Advanced Wine Assessment Course, we want to hear from you.

Since the course began in 1992, more than 800 people have attended and we want to keep our records up-to-date.

Please help us to keep your details current by clicking here. All information will remain confidential.

If you have not attended the course but would like more information or you’d like to join our mailing list, click here.

Congratulations Con!

Con Simos, the AWRI’s Group Manager Industry Development and Support, has been accepted for the 2010 Future Leaders Program, run jointly by the Australian Wine and Brandy Corporation, the Winemakers’ Federation of Australia, the Grape and Wine Research and Development Corporation and Wine Grape Growers’ Australia.

The Future Leaders Program brings together leading lights from Australia’s grape and wine sector to develop leadership, collaboration and networking skills, passing on the knowledge of current leaders to prepare for the industry’s future.

Vintage papers

It is that time of year and vintage is back on once again. Recent papers that have been published you might find useful can be requested below.

Technical Review Issue 182 – Yeast strains available for winemaking – 2009/2010

O’Kennedy, K. Wine yeast nutrients 101. Australian & New Zealand Grapegrower & Winemaker (550) : 99-104 ; 2009.

O’Kennedy, K. The case for co-inoculation of wine yeasts Australian and New Zealand Wine Industry Journal 23 (6) : 44; 2008.

Threlfall, R. T. Morris, J. Use of yeast supplements during wine production. Australian and New Zealand Wine Industry Journal 24 (6): 32-39 ; 2009.

Rensburg, P. van Pretorius, I. S. Enzymes in winemaking: harnessing natural catalysts for efficient biotransformations – a review. South African Journal of Enology and Viticulture 21 Special issue : 52-70; 2000.

Howell, G. Preparing your wine laboratory for vintage. Australian & New Zealand Grapegrower & Winemaker (551) : 86-88 ; 2009

Cowey, G. Coulter, A. Holdstock, M. Brines, paints, oils and the occasional mobile phone – common vintage contaminants. Australian & New Zealand Grapegrower & Winemaker 541, : 60-65 ; 2009.

Cuthbert, J. Gishen, M. Day, C. Oemcke, D. Taking the sting out of spoilage Australian and New Zealand Wine Industry Journal 23 (6) : 47-50; 2008.

Please contact the AWRI Library to request any of these publications.

Agrochemical Update September 2009

16 September 2009 >

FUNGICIDES

APVMA 63216

Kocide Opti has been granted registration by the Australian Pesticides and Veterinary Medicines Authority for the control of Downy mildew in grapevines.

Kocide Opti is a DuPont product. It contains the active constituent cupric hydroxide which is a Group M1 fungicide.

Restriction on use for export grapes: Use no later than 30 days before harvest.

APVMA 63940

Cop-IT has been granted registration by the Australian Pesticides and Veterinary Medicines Authority for the control of Downy mildew and Powdery mildew in winegrapes.

Cop-IT is an Agspec product. It contains the active constituent copper ammonium acetate which is a Group M1 fungicide.

Restriction on use for export grapes: Use no later than 30 days before harvest.

HERBICIDES

APVMA 31394

Roundup CT has been granted registration by the Australian Pesticides and Veterinary Medicines Authority for use in vineyards.

Roundup CT is a Nufarm product. It contains the active constituent glyphosate-ipa which is a Group M herbicide.

Note: LI-700 is one of the suggested surfactants that may be used with this product. It is advised that you contact your winery or grape purchaser prior to the use of LI-700.

APVMA 63316

Colt has been granted registration by the Australian Pesticides and Veterinary Medicines Authority for use on covercrops in vineyards.

Colt is a Farmoz product. This herbicide contains the active constituents bromoxynil and diflufenican which are classified as Group C and F respectively.

APVMA 61355

Fuzilier has been granted registration by the Australian Pesticides and Veterinary Medicines Authority for use in vineyards.

Fuzilier is an Ospray product. It contains the active constituent fluazifop-P which is a Group A herbicide.

Fuzilier has a label withholding period of four weeks.

INSECTICIDES

APVMA 62616

Clap has been granted registration by the Australian Pesticides and Veterinary Medicines Authority for the control of longtailed mealybug and tuber mealybug in winegrapes.

Clap is an Ospray product. It contains the active constituent buprofezin which is a Group 17A fungicide.

Restriction on use for export grapes: Use no later than 80% capfall.

Corrections to the AWRIs Dog Book Agrochemicals Registered for Use in Australian Viticulture 2009/2010

Page 6 and 12: The product Hydrocop contains the active constituent copper hydroxide not cuprous oxide.

Page 6: The active constituent metalaxyl is a Group D fungicide.

Page 7: The restriction on use for quinoxyfen is use no later than E-L stage 34 (before bunch closure) but do not use later than 42 days before harvest.

This information is provided to inform the wine industry of agrochemical product information, and should not be interpreted as an endorsement.

Agrochemical Update June 2009

22 June 2009 >

The AWRI publication Agrochemicals registered for use in Australian viticulture 2009/2010 is now available.

Major changes in the 2009/2010 Dog Book

1. Active constituents

None of the active constituents have been removed. However, methoxyfenozide (insecticide) and pine oil (herbicide) have been added.

METHOXYFENOZIDE

APVMA 61605

Prodigy has been granted registration by the Australian Pesticides and Veterinary Medicines Authority for the control of light brown apple moth in grapevines.

Prodigy is a Dow AgroSciences product. It contains the active constituent methoxyfenozide which is a Group 16A insecticide.

Prodigy (methoxyfenozide) now replaces Mimic (tebufenozide). However, tebufenozide remains in the 2009/2010 booklet as existing stocks are still registered for use in viticulture.

Restriction on use for export grapes: Use no later than 80% capfall.

PINE OIL

APVMA 62367

BioWeed has been granted registration by the Australian Pesticides and Veterinary Medicines Authority for the control of weeds in vineyards

BioWeed is a Certified Organics (Australia) product. BioWeed is a contact herbicide, containing the active constituent pine oil for which the activity group is unspecified.

2. Restrictions on use

The major change to note is the recommended export withholding period for procymidone.

The 2009/2010 restriction on the use of products which contain the active constituent procymidone is “Not recommended for use on grapes destined for export wines”.

3. Content – changes to the fungicide activity group codes

The main additions in content in the three sets of tables in the Dog Book are a result of changes to the fungicide activity group codes.

CropLife Australia has changed the activity group codes for fungicides to bring them in line with International codes. None of the groupings change, they have simply been assigned a new code. Chemical companies have three years in which to change their product labels to reflect these new codes so it is expected that there will be a mix of old (pre 2009) and new (from 2009) activity group codes for fungicide products over the next two years. Therefore, we have made changes to Table 1. Recommendations, Table 2. Agrochemicals registered for use in Australian viticulture and Table 3. Fungicide resistance management strategies

Recommendations: The activity group codes for all active constituents have been added to this table. Only the old (pre 2009) activity group codes for fungicides have been added because most product labels do not reflect these changes as yet. Due to a space restriction we have replaced activity codes that are unspecified with n/a.

Agrochemicals registered for use in Australian viticulture: Both the old (pre 2009) and new (from 2009) activity codes for fungicides are displayed in this table.

Fungicide resistance management strategies: CropLife Australia have re-written the resistance management strategies for botrytis, downy mildew and powdery mildew which replaces the old (pre 2009) fungicide activity group codes with the new (from 2009) codes. To make it easier to develop an appropriate spray program which takes into account the three fungicide resistance management strategies we have provided the corresponding old (pre 2009) activity group codes until all product labels have been updated.

4. Permits

APVMA: Permit number 11015

Permit 11015 replaces permit 10127. Permit 11015 currently issued by the Australian Pesticides and Veterinary Medicines Authority, allows the use of Sumi-Alpha Flex (containing 50 g/L esfenvalerate as its only active constituent) for the control of Garden weevil in grapevines grown in Tasmania and Western Australia. This permit expires on 28 August 2009.

Restriction on use for export grapes: Use no later than 80% capfall.

For other permit information visit the AWRI agrochemical website http://www.awri.com.au/industry_support/viticulture/agrochemicals/

5. AWRI Online Search Facility for Agrochemicals.

The AWRI has developed an ‘Online Search Facility for Agrochemicals’ which provides a searchable web-based format, delivering a more efficient way of retrieving agrochemical information currently available on the AWRI website.

Using this facility, users can rapidly access information contained in the current AWRI publication Agrochemicals registered for use in Australian viticulture (often called the ‘Dog Book’). It also provides additional information derived from the AWRI agrochemical database which is not published in the Dog book.

The new AWRI Online Search Facility for Agrochemicals can be accessed by visiting the agrochemical section of the AWRI website http://www.awri.com.au/agrochemicals/

6. Other agrochemical issues
‘Sunscreen’ products do not require APVMA registration.
Due to another hot and dry season, the use of products such as Surround and Screen were being considered as a way of reducing leaf temperatures relative to ambient temperatures.

Surround and Screen as protectants against sunburn and heat stress are not required to be registered by the APVMA and there is no State or Territory legislation regulating their use. The registration process is governed by Commonwealth legislation. The agricultural chemical products that require registration encompasses all herbicides, insecticides, fungicides and growth regulators. It does not include products such as Surround and Screen because they do not fit the definition of an ‘agricultural chemical product’ (For more information on this definition go to http://www.apvma.gov.au/registration/chemreg.shtml). Therefore, Surround and Screen can be used on grapevines despite the fact that grapevines do not appear on the label. Given the nature of the product, residues might be present at harvest, especially in the case of late season applications. We do not know if this will have any impact on the winemaking process and final wine quality. It is advised that you contact your winery or grape purchaser prior to application of these products

This information is provided to inform the wine industry of agrochemical product information, and should not be interpreted as an endorsement.