Wine & Viticulture Journal Autumn 2024 FREEVIEW

AUTUMN

• Is TCA in the air a threat for bottled wine?

• Climate change consequences for Pinot Noir berry quality

• Managing wine portfolios for growth

• Tasting: Reduced and No & Low Alcohol Still White Wines

INDUSTRY ASSOCIATION COLUMNS

8 WINE AUSTRALIA (Martin Cole): Driving growth through products that meet consumer demands

9 AGW (Lee McLean): There’s never been a more important time for governments to invest in the wine industry

10 ASVO (Andy Clarke): Post-vintage events ripe for the picking

WINEMAKING

12 The influence of mushroom chitosan on caftaric acid and furan-derived aroma compounds in Pinot Noir juice and base wine

21 Is TCA in the air a threat for bottled wine?

33 AWRI REPORT: NOLO wine — laying the groundwork for big steps forward

VITICULTURE

30 Cover crops and no-tillage show negligible effects on grapevine physiology in warm and hot climates

45 Performance of genetically diverse phylloxera genotypes on 5C Teleki rootstock

52 TONY HOARE: Managing vineyards in heatwaves – Part 1

56 Turning up the heat: climate change consequences for Pinot Noir berry quality

60 Grapevine trunk disease pathogen spore detection varies within and around vineyards

66 The latest research on grapevine virology: Highlights of the 20th International Council for the Study of Virus and Viruslike Diseases of the Grapevine meeting

71 ALTERNATIVE VARIETIES: Counoise

BUSINESS & MARKETING

73 Rebalancing Australian wine supply and demand remains a challenge despite small reduction in wine inventory in 2022-23

75 Managing wine product portfolios for growth

77 Which are Australia’s emerging winegrape varieties?

TASTING

86 Reduced and no and low alcohol still white wines

Kym Anderson

Matthew Ayres

Regina Billones-

Baaijens

Bernedette

Carmody

Andy Clarke

Catherine Clarke

Justin Cohen

Martin Cole

John Paul

Cunningham

Peter Dry

Scott Gregan

Nuredin Habili

Sandy Hathaway

Jessica Henneken

Tony Hoare

Belinda Hughes

Brian Jordan Rainer Jung

Belinda Kemp

Mark Krstic

S. Kaan Kurtural

Meifang Liu

Lauren Marigliano

Jacob Medeiros

Lee McLean

Judit Monis

Romy Moukarzel

Amber Parker

Wes Pearson

Gary Pickering

Germán Puga

Sandra Savocchia

Olaf Schelezki

Duncan Shouler

Mark Sosnowski

Justin Tanner

Andrii Tarasov

Nazereth Torres

Shufen Xu

Runze Yu

Daniele Zaccaria

Maria Zumkeller

It’s been quite the start to the New Year for the Australian wine industry.

First, there was the release in early January of the long-anticipated draft of the One Grape & Wine Sector Plan — the document designed to outline what the industry needs to prioritise between now and 2030 to address its near and present challenges.

And then came the news just as this issue of the Wine & Viticulture Journal was being finalised for print in late March that China had decided to remove the anti-dumping duties it imposed on Australian wine in March 2021 for what was supposed to be five years.

Suffice to say, the draft One Grape & Wine Sector Plan, which the boards of Australian Grape & Wine (AGW) and Wine Australia (WA) identified a need for in September 2022 and was based on sector-wide consultation which ran from July to October 2023, was met with largely unfavourable reactions from members and observers of the wine industry.

Ross Brown, executive director of the Brown Family Wine Group, said his company expected the document to have a “strategic focus with measurable and actional outcomes”. Instead, he said it “lacks strategy and doesn’t define clear actions for the industry” and presented “nothing bold or substantially different to the status quo”. Andrew Weeks, former chief executive of Australian Vignerons (which merged with the Winemakers’ Federation of Australia in 2019 to become Australian Grape & Wine), lamented the fact that the plan has “no clear articulation of the key problems that the wine sector is facing” and “has limited chance of success”. Even the Australian Wine Research Institute, which curiously failed to rate a mention in the draft plan’s list of ‘sector bodies supporting the success of the grape and wine sector’, described it as “a plan to plan” in its formal submission in response to the plan.

After the feedback period to the plan ended on 5 February, AGW and WA, the organisations that have been leading the development of the plan, wrote to industry and noted that “most respondents raised the need to better define the plan’s next steps”. While confirming that the plan aims to “highlight the collective priorities identified by the grape and wine sector to encourage greater alignment of activity across the industry” it was not “a prescriptive plan”. “It will be up to each organisation, including representative organisations and individual businesses, to assess the plan and set their own targets.”

AGW and Wine Australia, with the assistance of consulting firm ACIL Allen, are now in the process of “refining and enhancing” the plan to “reshape the final document” which is scheduled for release mid-year.

The One Grape & Wine Sector Plan is being developed in response to “unprecedented challenges” impacting the industry. China’s decision to impose antidumping duties on Australian bottled wine was one of those challenges. After peaking at $1.3 billion in the 12 months ended October 2020, Australian wine exports to China totalled just $10.1 million in the 12 months ended December 2023. And to think the tariffs had two years to run until AGW convinced China in November last year to review the need for the duties!

According to statistics from Trade Data Monitor, total wine imports to China fell from 688 million litres in 2018 to 248 million litres in 2023 – a third of what it was five years ago. Clearly, Australian wine is highly unlikely to enjoy the peaks it once did anytime soon, but it’s a welcome win nonetheless. Even China is hoping that having our products back in the marketplace will provide some much-needed competition to alleviate the rising prices of its existing imported wines and stimulate the overall domestic demand for wine, including its own home-grown products.

INDUSTRY OUTLOOK

TASKFORCE FORMED TO ADDRESS INDUSTRY CHALLENGES

Commonwealth, state and territory agriculture ministers agreed to establish a viticulture and wine sector working group following an agriculture ministers’ meeting on 8 March.

The formation of the working group was in response to “the significant challenges facing winegrape growers, particularly in the inland regions”, a communique of the meeting revealed.

The working group will comprise representatives of the Commonwealth, state and territory governments, Wine Australia, Australian Grape and Wine and other relevant groups as agreed by the working group, “to provide recommendations to Agriculture Ministers to address the challenges facing growers”, particularly the current oversupply of red winegrapes.

The working group was expected to visit regions most impacted by the oversupply, including the Riverland in SA and the Riverina in NSW, reporting back to agriculture ministers by the end of April 2024.

“The working group will also propose to agriculture ministers actions to support improvement in the grape and wine sector and its long-term viability by July,” the communique said.

Australian Grape & Wine (AGW) welcomed the formation of the work group.

“Australian Grape & Wine has been encouraging a coordinated and collaborative approach to deal with the challenges our sector is facing and we are pleased Ministers have agreed to form this working group,” said AGW chief executive Lee McLean.

“We know there are a number of regions experiencing acute financial pressure as a result of supply and demand imbalances, including the Riverland in South Australia, the Riverina in NSW, and the Murray Valley in Victoria, and it’s pleasing the group will focus on ways we can work together to relieve these pressures in these regions,” he said.

“Australian Grape & Wine has put a range of options to the Albanese Government ahead of the Federal Budget, including proposals to help rebalance supply, grow demand and boost regional tourism. These proposals are all aimed at helping Australia’s grapegrowers and winemakers to find a pathway through the current

challenges towards a sustainable and more profitable future.”

Lee said the formation of the working group was a reflection of the strong working relationship that AGW had developed with the Australian Government.

INDUSTRY AWAITS FINALISED ONE SECTOR PLAN

The Australian wine industry is awaiting the release of the finalised One Grape & Wine Sector Plan following publication of the draft document in early January.

Developed jointly by Australian Grape & Wine (AGW) and Wine Australia (WA), the draft ‘One Sector Plan’ is aimed at directing the collective efforts of the industry in response to its recent challenges and to get the sector back on track to achieving the longterm goals set out in Vision 2050.

The draft plan was informed by sector-wide consultation which was carried out from July to October 2023.

Members of the wine industry were given until 5 February 2024 to provide feedback on the draft plan. AGW and WA subsequently advised that the views it received in response to the draft plan were “insightful and varied”.

“In light of your feedback, we are committed to refining and enhancing the One Grape & Wine Sector Plan to reflect the collective vision and aspirations of the industry. We intend to release the final One Grape & Wine Sector Plan mid-year,” said AGW chief executive Lee McLean and WA chief executive Martin Cole in an email to industry on 16 February.

“While the feedback received will be

considered as we reshape the final document, we note that most respondents raised the need to better define the plan’s next steps, and we would like to take the opportunity to respond to this now to explain our view of what the plan is designed to do and what it will be used for.

“Our objective for the One Grape and Wine Sector Plan is to help organisations and businesses to find opportunities to collaborate where they can for the common good of the industry, drawing upon the priorities grapegrowers, winemakers, representative organisations, research institutions and others have identified throughout the consultation process,” Cole and McLean said.

“This is not a prescriptive plan. It will be up to each organisation, including representative organisations and individual businesses, to assess the plan and set their own targets. This reflects the fact that while we should be united where we can, there will be areas in which our priorities will differ. It also reflects the individual governance arrangements that every organisation in the industry must abide by in crafting their own plans.”

The draft One Grape & Wine Sector Plan can be downloaded here: www.wineaustralia. com/whats-happening/one-sector-plan

WINE EXPORTS

CHINA REMOVES DUTIES ON AUSTRALIAN BOTTLED WINE

The duties on Australian bottled wine imports into Mainland China were removed from 29 March 2024 following a review of the duties by China’s Ministry of Commerce (MOFCOM).

MOFCOM determined that, “in view of the changes in the relevant wine market conditions in China, it is no longer necessary to impose anti-dumping duties and countervailing duties on imported relevant wines originating in Australia”.

In advising of its decision, MOFCOM noted that the quantity of wine imported from Australia had dropped sharply since the introduction of the anti-dumping duties in late March 2021 and the source of China’s wine imports had adjusted accordingly. During the same time, the local demand for domestic wine had declined due to various factors including the competition from different product categories.

The influence of mushroom chitosan on caftaric acid and furan-derived aroma compounds in Pinot Noir juice and base wine

By Jacob Medeiros1, Shufen Xu2, Gary J. Pickering1,2,3,4 and Belinda S. Kemp5*

The excessive accumulation of phenolic compounds in winegrapes destined for sparkling wine production can be unavoidable in some years to achieve desirable ripeness levels. These compounds can be removed through the use of fining agents such as polyvinyl-polypyrrolidone (PVPP). Chitosan, a naturally synthesised biopolymer derived from crustacean exoskeletons and the cell walls/root structures of fungi, has been proposed as a more sustainable alternative to these fining agents This study set out to determine the ability of mushroom-derived chitosan to reduce the concentration of the phenolic compounds caffeic and caftaric acid in Pinot Noir grape juice, and to establish the synthesis of furan-derived aroma compounds during storage when it is added to sparkling base wine.

INTRODUCTION

Winegrapes destined for traditional method sparkling wine production are typically hand harvested and whole bunch pressed to minimise the extraction of phenolic compounds into the juice (Charnock et al. 2022). The excessive accumulation of these compounds may be unavoidable in some years to attain appropriate ripeness levels for sparkling wine production (Chamkha et al. 2003) In these years, the removal of phenolic compounds from grape juice is possible through the use of fining agents such as polyvinyl-polypyrrolidone (PVPP) or activated carbon (Spagna et al. 2000). More recently, crustacean- and fungiderived chitosan have been proposed as more

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sustainable alternatives to these fining agents (Vendramin et al. 2021), reflecting wider industry initiatives towards, and consumer interest in, sustainable wines (Baiano 2021, Pickering and Best 2023).

Chitosan is a naturally synthesised biopolymer derived from crustacean exoskeletons and the cell walls/root structures (mycelium) of fungi (such as Aspergillus niger and Agaricus bisporus) (Silva et al. 2020). Formed via the deacetylation of chitin, it is one of the most abundant biopolymers on Earth (Vendramin et al. 2021). Chitosan molecules are chemically defined by their molecular weight (MW) and degree of deacetylation (DD), which refers to the proportion of the

IN BRIEF

■ Chitosan is a fining agent used in winemaking and has antimicrobial properties, although its use in juice and wine beyond these applications has been limited until now.

■ This study aimed to determine if chitosan derived from button mushrooms could reduce caffeic and caftaric acid concentrations in Pinot Noir grape juice.

■ It also aimed to determine if chitosan, when added to base wine, could influence the formation of furan-derived aroma compounds during storage.

■ The results demonstrate the potential of mushroom-derived chitosan to remove caftaric acid from grape juice and suggest that chitosan influences the synthesis of furan-derived compounds in wine after short-term storage.

monomer units that are N-deacetylated (Abd El-Hack et al. 2020). In 2009, the International Organisation of Vine and Wine (OIV) authorised the use of fungal chitosan (derived from A. niger) in the winemaking process to improve flocculation of suspended solids and proteins, thereby decreasing

*Correspondence: Belinda.Kemp@NIAB.com

Cover crops and no-tillage show negligible effects on grapevine physiology in warm and hot climates

By Maria Zumkeller1, Nazereth Torres2, Runze Yu3, Lauren E. Marigliano1, Justin D. Tanner1, Daniele Zaccaria4 and S. Kaan Kurtural1

Researchers evaluated the effects of annual or perennial cover crops and tillage regimes on whole grapevine physiology and berry composition in both a hot and warm climate in the US state of California.

INTRODUCTION

In the last decade, there has been a rise in the adoption of sustainable soil management practices that reduce soil erosion and bolster soil organic matter to counter the impacts of climate change on agricultural soils (Lal 2004a, Powlson et al. 2011a, Lal 2012a, Lazcano et al. 2020a).

Traditionally, vineyard rows were kept bare with the use of herbicides and tillage. However, there is disagreement on the utility of this practice due to the detrimental effects of tillage on air quality and soil physical, chemical and biological properties (Patiño-Zúñiga et al 2009a, Ferreira et al. 2020, Gatti et al. 2022a). Thus, the adoption of cover crops and reduced tillage is considered a sustainable alternative to the traditional management of vineyard floors (Alsina et al. 2013b). Furthermore, environmental regulations and public perception serve as an additional incentive to adopt climate-smart practices (Guerra and Steenwerth 2012).

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IN BRIEF

■ Researchers studied the effects of tillage and cover crops on grapevine water status, leaf gas exchange, components of yield, berry composition and the resulting water footprint in a hot (Fresno County) and warm climate (Napa County) in California.

■ The variety involved in the Fresno County site was Ruby Cabernet/Freedom; the variety at the Napa County site was Merlot.

■ Treatments included perennial grass, resident vegetation and an annual grass grown under conventional tillage and no-till settings.

The benefits of cover crops on the properties of soils are well documented. They can increase soil organic matter (SOM), total nitrogen, microbial biomass, β-glucosidase, and alkaline phosphomonoesterase, improve water infiltration and aggregate stability, reduce soil erosion and greenhouse gas emissions (GHG), and increase vineyard biodiversity (Ingels et al. 2005, Steenwerth and Belina 2008b, Gattullo et al. 2020, Abad et al 2021, Zumkeller et al. 2023). Nevertheless, the adoption of cover crops in vineyards is limited by the concern of excessive competition between the cover crop and grapevine for water and nutrients (Smith et al 2008, Steenwerth and Belina 2008a, Celette et al. 2009a, Steenwerth et al. 2013, PérezBermúdez et al. 2016). Thus, the presence of a cover crop is generally reported to affect grapevine water status detrimentally (Naor et al. 1997, Monteiro and Lopes 2007, Hatch et al. 2011a, Pou et al. 2011, Steenwerth et

■ Under the experimental conditions of the study, in both the hot and warm climate vineyard cover cropping had negligible beneficial effects on grapevine physiology, mineral nutrition or productivity with no detrimental effects on vineyard water footprint.

■ Tillage was shown to be beneficial in younger vineyards to improve plant water status in semiarid regions.

al. 2016, Tomaz et al. 2021). Despite wide acceptance of this particular effect, results depended on the specific conditions of the study, as some studies have shown that cover crops may improve early-season water status (Ingels et al. 2005, Delpuech and Metay 2018, Reeve et al. 2016); yet others have

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3Department of Viticulture and Enology, California State University, Fresno, California, United States of America

4Department of Land, Air and Water Resources, University of California Davis, Davis, California, United States of America