A multi-faceted, multi-agency project has confirmed that blending or dilution with unaffected wine can be an effective remedy for smoke-affected wine.
It is welcome news for growers and winemakers with fruit that has been affected by smoke from recent bushfires across the country.
‘The message is clear: not all hope is lost when it comes to smoke-affected fruit’, said Australian Wine Research Institute (AWRI) Research Scientist, Dr Julie Culbert. ‘Blending trials will help you determine if a final wine blend with suitable sensory properties can be achieved.’
Julie was part of the AWRI team working on the ‘smoke taint’ mitigation project funded by the Department of Agriculture, Water and the Environment’s Rural R&D for Profit program and Wine Australia, and recently finalised a factsheet on dilution to treat smoke tainted wine.
The smoke taint 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 is one option for managing a smoke-affected wine, and this was evaluated in one part of the project.
The trial took a smoke-affected 2019 Pinot Noir rosé wine and then blended it with an unaffected Pinot Noir wine of a similar style sourced from the same vintage.
A dilution series of 6 samples – 100 per cent smoke-affected wine, 50 per cent smoke-affected wine, 25 per cent smoke-affected wine, 12.5 per cent smoke-affected wine, 6.25 per cent smoke-affected wine and 0 per cent (equivalent to 100 per cent unaffected wine) – was created and then assessed by members of the AWRI’s technical quality panel for ‘smoke’ aroma and flavour and ‘overall fruit’ aroma and flavour.
‘As expected, the 100 per cent smoke-affected wine was scored significantly higher in “smoke” aroma and flavour than the unaffected wine and was the lowest scoring wine for “overall fruit” aroma and flavour’, Julie said. ‘Dilutions of the affected wine with 75 per cent or more unaffected wine resulted in ‘smoke’ aroma and flavour scores not significantly different from the unaffected wine.’
Julie said the findings of the dilution study on the smoke-affected Pinot Noir didn’t really surprise the team.
‘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,’ she said.
‘In this case, we were able to blend away smoke taint in the 100 per cent smoke affected Pinot Noir rosé wine by adding more than 75 per cent unaffected wine.’
However, Julie stressed that 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.
‘This is where blending trials can play an important role in decision-making. We recommend conducting trials on small volumes of wine to determine a final wine blend with suitable sensory characteristics.
‘And, as with all remediation treatments, producers should consider the costs and benefits of a dilution approach and their own individual circumstances and wine characteristics.’
Top tips to manage smoke taint from harvest through to final product
- hand harvest fruit
- exclude leaf material
- maintain integrity of harvested fruit (avoid maceration and skin contact)
- keep fruit cool
- whole bunch press
- separate press fractions
- conduct trials with fining agents
- minimise fermentation time on skins
- consider addition of oak chips and tannin
- consider reverse osmosis of wine (although the smoke characters might return over time), and
- market for quick sale.[1]
The smoke taint project was supported by the AWRI, through funding from the Australian Government Department of Agriculture, Water and the Environment as part of its Rural R&D for Profit program and Wine Australia. Project partners included the AWRI, Agriculture Victoria, LaTrobe University, Wine Victoria and CRC Polymers.
Want to learn more?
Wine Australia has a range of resources on fire and smoke assessment on its website here, as does the AWRI here, which also provides factsheets on treating smoke affected wine.
[1] Source: AWRI fact sheet: Smoke Taint – practical management options for grape growers and winemakers.