Where there’s smoke there’s not necessarily taint

This project is supported by funding from the Australian Government Department of Agriculture and Water Resources as part of its Rural R&D for Profit programme.

The most concerted effort yet to understand how, when, where and why smoke affects wine grapes kicks into gear this vintage.

Victorian-based researchers will accompany authorities to the site of controlled burns in and around wine regions to monitor the movement and make-up of the smoke to get a better idea of the patterns of impact.

‘The missing component in all the research that’s been done to date is the smoke composition work,’ said co-project leader Dr Ian Porter. ‘The damaging compounds aren’t in all smoke and they drop out at a certain distances from a fire, so which fires are and aren’t they in?’

The project is one part of a twin assault being funded Australian Government Department of Agriculture and Water Resources as part of its Rural R&D for Profit programme, the Victorian Government, the Australian Wine Research Institute (AWRI), La Trobe University and Wine Australia.

While Dr Porter and colleagues at Agriculture Victoria and La Trobe are working on ‘the pre-emptive side of things’, researchers at the AWRI, led by Dr Mark Krstic, will run a concurrent program looking at how to limit uptake by fruit and ameliorate juice and wine when a smoke taint event does occur. Together the teams will look at mitigation treatments in the vineyard and wine.

‘The overlap is that we are working cooperatively on understanding the sensory wine threshold levels in different wines’, said Dr Porter, who spreads his time between La Trobe and Agriculture Victoria.

Minimising the impact of wildfires on wine grapes is important in wine regions globally. There is equal concern about the impact of controlled burns, which are mandatory in Victoria and therefore occur regularly. Many people fear that any fire brings smoke and that all smoke poses a problem, even low level haze, but studies to date suggest that this may not be the case.

‘The important factor – and we didn’t really understand just how important it is until about three years ago – is that particulate matter in smoke haze does not necessarily mean there are damaging compounds in it. Now we can take that knowledge further. I think we are going to take great strides in the next three years.’

Dr Ian Porter

While the project will be intense, logistically difficult and not without risk, some important lead-up work has already been done.

First, the Victorian Government funded a $4 million project at the Centre for Expertise in Smoke Taint Research, which provided key scientific information about the free and bound compounds that cause smoke taint and how they get in to the berries.

Then Dr Porter and his team were able to do preliminary field sampling at controlled burns last Autumn while working in collaboration with the Department of Environment, Land, Water and Planning (DELWP).

Ten remotely accessible smoke detectors were set up in major vineyards – three in North Eastern Victoria (the King and Ovens Valleys), three in the Yarra Valley and others at the fire front – and data was captured on the distribution of particulate matter in smoke haze across a full season of controlled burns. Smoky air also was sampled to determine the chemical composition at varying distances from the fire front.

The work allowed the research team to not only test their monitoring procedures, but also to get to grips with the complex issues around access and communications and learn the safety protocols. With the method in place, they can get down to the targeted data collection in the new project.

‘The key question now is how far do you need to be downwind of a fire to get the concentration of the compounds and for how long do you need to be exposed to get taint?’, Dr Porter said. ‘You can get taint in 10 minutes if you are right next to a fire, however the compounds change very rapidly. So what does it mean if you’re 500 metres or 10 kilometres away or are subject to low level smoke for several weeks?