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New research says ‘not all hope lost' when it comes to smoke taint

Published:  08 April, 2020

A multi-faceted, multi-agency smoke taint project, supported by the Australian Wine Research Institute (AWRI) and funded by the Australian government, has confirmed that blending or dilution with unaffected wine can be an effective remedy for smoke-affected wine.

AWRI said the project had three major objectives: to develop an early warning remote sensing network for monitoring real-time levels of smoke; to evaluate a range of possible preventative measures to reduce uptake of smoke compounds in the vine and grapes; and to evaluate remedial management options for dealing with smoke-affected grapes and wine.

Dilution with unaffected wine was one option for managing a smoke-affected wine, it said, and this was evaluated in one part of the project,

Following the trial, “the message was clear - not all hope is lost when it comes to smoke-affected fruit”, said AWRI research scientist, Dr Julie Culbert, who recently finalised a factsheet on dilution to treat smoke tainted wine.

“Blending trials will help you determine if a final wine blend with suitable sensory properties can be achieved.”

The trial was based on blending a smoke-affected 2019 Pinot Noir rosé and with an unaffected Pinot Noir wine of a similar style sourced from the same vintage.

A dilution series of six samples – 100% smoke-affected wine, 50% smoke-affected wine, 25% smoke-affected wine, 12.5% smoke-affected wine, 6.25% smoke-affected wine and 0% (equivalent to 100% unaffected wine) – was created and then assessed for ‘smoke’ aroma and flavour and ‘overall fruit’ aroma and flavour.

As expected, the 100% smoke-affected wine scored significantly higher in ‘smoke’ aroma and flavour than the unaffected wine and was the lowest scoring wine for ‘overall fruit’ aroma and flavour,” said Culbert. 

“Dilutions of the affected wine with 75% or more unaffected wine resulted in ‘smoke’ aroma and flavour scores not significantly different from the unaffected wine.”

The findings of the dilution study on the smoke-affected Pinot Noir “didn’t really surprise the team”, she added. 

“We knew if we could add sufficient unaffected wine to reduce the smoke compounds to concentrations close to or below background concentrations (found in non smoke-affected wine) then it should reduce or eliminate the smoke character of the diluted wine.

“In this case, we were able to blend away smoke taint in the 100% smoke affected Pinot Noir rosé wine by adding more than 75% unaffected wine,” she said. 

However, stressed Culbert, the level of dilution required to dilute smoke characters sufficiently would differ from wine to wine – depending on the level of smoke compounds in the wine and the sensory properties of the unaffected wine used as the blending wine.

The funding for the project from the Australian Government Department of Agriculture, Water and the Environment forms part of its Rural R&D for Profit program.

Andreas Clark, CEO, Wine Australia told Harpers: “Wine Australia’s investments in this area span 15 years and more recently have aimed to develop a comprehensive range of solutions for the sector.

“This particular project was a perfect example of the complexities involved; as it considered preventative actions in the vineyard – both using new technologies to develop an early warning system and application of barrier sprays to the grapes – and different remedial options for when fruit is affected by smoke.

“Culbert’s dilution technique was investigated concurrently with other winery treatments such as use of activated carbon to absorb smoke compounds, and use of enzymes to degrade smoke compounds,” he said.

Research into the effect of smoke on grapes and wine was ongoing, he added, with samples and data collected from the fires this season providing “valuable material to assist the development of management solutions”.

“The ultimate aim of all research completed in Australia is to provide our grape and wine community with innovative and cost-effective solutions that have a rigorous, scientific evidence-base and can be confidently relied on to ensure that winemakers can produce wines that consumers can enjoy without unwanted flavours.”