Grampians Fires

[I Love Shiraz]

With the large bushfire burning in the Grampians the last 2-3 days, I wonder what affect it may have on the vineyards in the region. Are the grapes large enough for the fires to cause smoke taint?

[cuttlefish]

I think it's too early in the fruits development for there to be any negative impact from smoke. They're only just going through veraison, I believe. Some may be a tiny bit further along, but nothing to worry about at this point. An actual firefront across your vineyard would be a different story, but I haven't heard of anything of that nature.

[Sean]

Looks like we are in for another long summer of bushfires unfortunately, and the risk to wildlife, property and lives.

The CFA does a great job of course. But often these bushfires are burning in inaccessible areas and go large scale. They will do back burning to limit or impede the spread of bushfire if they can. But they are mostly using resources to protect property such as homes, farming sheds, livestock - and human life.

The really big bushfires are never put out unless there is a rain event. They can keep burning for months and unless there is a threat to the small rural hamlets in these areas they will wait for them to burn out. As we saw in the Black Summer bushfires, however, the fire threat can start up and pose another, bigger threat all over again.

Those bushfires started in November 2019 and were still going in February 2020. You might remember the Gippsland bushfire that came down out of the ranges and burned down to the ocean. At Mallacoota there were 60 houses destroyed and people had gathered at the foreshore watching the country burning around them. On 3 January, nearly 2,000 people were evacuated by the Royal Australian Navy.

By the end of the 2019/20 bushfires in Victoria alone, five lives were lost and it had destroyed over 300 homes and 6,600 livestock. The fires burned up more than 1.5 million hectares of land, including private land, parks, critical animal habitats and water catchment areas. (Source - Australian Government website)

Across Australia (so including SA, Queensland and NSW), 33 people died including nine firefighters. More than 3,000 homes had been destroyed and 17 million hectares of land had burned.

So this is what people will be worried about.

But to answer the question from the OP, it seems that the AWRI has changed its thinking on the issue of smoke taint.

I also remember it being associated with the veraison stage. That was probably because we understood that smoke taint was absorbed by the waxy cuticle on the berries. There was also often discussion whether this affected red grapes (because they use skins and pulp in the winemaking) much more than white grapes. Both of these assumptions are now being questioned and investigated by the AWRI.

“The effects of smoke exposure vary depending on stage of grapevine growth and development when smoke exposure occurs. In the past it was believed that early-season smoke exposure posed lower risk than exposure close to harvest; however, data from Australian smoke events in 2019/20 showed that there is a significant risk of perceptible smoke characters in wine, even when smoke exposure occurs prior to veraison.” - AWRI fact sheet ‘Smoke taint - entry into grapes and vineyard risk factors’ (October 2023)

This fact sheet also sets out a basic guideline on risk of smoke taint based on the stages of development of the grapevines.

Grapevine shoots 10cm in length - Low risk
Flowering - Low risk
Berries pea size - Variable to high risk
Beginning of bunch closure - Variable to high risk
Onset of veraison - Variable to high risk
Post-veraison to harvest - High risk

Vineyard owners who think they might have smoke taint are encouraged to get a testing kit from the AWRI four weeks before harvesting.

The AWRI is more interested in smoke-related volatile phenols in the grapevine, not just its accumulation on the berries. I am thinking it must be because they are focusing on the chemistry of this rather than the physical side to it - or simply the resultant how grapes taste and sensory wine experience. Smoke is made up of “particulate” matter as well as volatile phenols, and this is what they are measuring using nephelometry - although none of this is conclusive and more a work in progress.

This is probably getting more attention, because we are getting these longer duration bushfire events over summer rather than a bushfire event per se. The impact of bigger bushfires or even back burning will have an impact for vineyard owners, even if they are not directly threatened by a bushfire.

Wineries across different areas of the country were impacted by those Black Summer bushfires in 2019/20 from the Adelaide Hills in SA to Hunter Valley to southern NSW and Gippsland. For example, the Mount Pleasant winery in Hunter Valley scrapped their entire 2020 vintage and Tyrrell’s lost 80% of their crop because of smoke taint. Bruce Tyrrell said - “We didn’t have any immediate fire, we just had the smoke hanging around.” (Source - The Guardian)

So now there are bushfires around eastern areas of the Grampians in Victoria. The out of control bushfire in the Grampians National Park has now burned up 55,000 hectares of bushland. They have had fire threatened areas around Halls Gap, Moyston and Pomonol over the last couple of weeks and it is continuing through today.

Back in February 2024 there was a bushfire in the Mt Cole valley and Pomonal areas, which destroyed a number of homes and primary school in the town. Also a Grampians winery named Mountainside decided not to pick the 2024 vintage because of smoke taint. Thankfully other wineries in the Grampians reported they were not affected by that bushfire (Source - ABC News).

Everyone out there will be watching the bushfire season this summer very closely.

[I Love Shiraz]

Looks like we are in for another long summer of bushfires unfortunately, and the risk to wildlife, property and lives.

The CFA does a great job of course. But often these bushfires are burning in inaccessible areas and go large scale. They will do back burning to limit or impede the spread of bushfire if they can. But they are mostly using resources to protect property such as homes, farming sheds, livestock - and human life.

The really big bushfires are never put out unless there is a rain event. They can keep burning for months and unless there is a threat to the small rural hamlets in these areas they will wait for them to burn out. As we saw in the Black Summer bushfires, however, the fire threat can start up and pose another, bigger threat all over again.

Those bushfires started in November 2019 and were still going in February 2020. You might remember the Gippsland bushfire that came down out of the ranges and burned down to the ocean. At Mallacoota there were 60 houses destroyed and people had gathered at the foreshore watching the country burning around them. On 3 January, nearly 2,000 people were evacuated by the Royal Australian Navy.

By the end of the 2019/20 bushfires in Victoria alone, five lives were lost and it had destroyed over 300 homes and 6,600 livestock. The fires burned up more than 1.5 million hectares of land, including private land, parks, critical animal habitats and water catchment areas. (Source - Australian Government website)

Across Australia (so including SA, Queensland and NSW), 33 people died including nine firefighters. More than 3,000 homes had been destroyed and 17 million hectares of land had burned.

So this is what people will be worried about.

But to answer the question from the OP, it seems that the AWRI has changed its thinking on the issue of smoke taint.

I also remember it being associated with the veraison stage. That was probably because we understood that smoke taint was absorbed by the waxy cuticle on the berries. There was also often discussion whether this affected red grapes (because they use skins and pulp in the winemaking) much more than white grapes. Both of these assumptions are now being questioned and investigated by the AWRI.

“The effects of smoke exposure vary depending on stage of grapevine growth and development when smoke exposure occurs. In the past it was believed that early-season smoke exposure posed lower risk than exposure close to harvest; however, data from Australian smoke events in 2019/20 showed that there is a significant risk of perceptible smoke characters in wine, even when smoke exposure occurs prior to veraison.” - AWRI fact sheet ‘Smoke taint - entry into grapes and vineyard risk factors’ (October 2023)

This fact sheet also sets out a basic guideline on risk of smoke taint based on the stages of development of the grapevines.

Grapevine shoots 10cm in length - Low risk
Flowering - Low risk
Berries pea size - Variable to high risk
Beginning of bunch closure - Variable to high risk
Onset of veraison - Variable to high risk
Post-veraison to harvest - High risk

Vineyard owners who think they might have smoke taint are encouraged to get a testing kit from the AWRI four weeks before harvesting.

The AWRI is more interested in smoke-related volatile phenols in the grapevine, not just its accumulation on the berries. I am thinking it must be because they are focusing on the chemistry of this rather than the physical side to it - or simply the resultant how grapes taste and sensory wine experience. Smoke is made up of “particulate” matter as well as volatile phenols, and this is what they are measuring using nephelometry - although none of this is conclusive and more a work in progress.

This is probably getting more attention, because we are getting these longer duration bushfire events over summer rather than a bushfire event per se. The impact of bigger bushfires or even back burning will have an impact for vineyard owners, even if they are not directly threatened by a bushfire.

Wineries across different areas of the country were impacted by those Black Summer bushfires in 2019/20 from the Adelaide Hills in SA to Hunter Valley to southern NSW and Gippsland. For example, the Mount Pleasant winery in Hunter Valley scrapped their entire 2020 vintage and Tyrrell’s lost 80% of their crop because of smoke taint. Bruce Tyrrell said - “We didn’t have any immediate fire, we just had the smoke hanging around.” (Source - The Guardian)

So now there are bushfires around eastern areas of the Grampians in Victoria. The out of control bushfire in the Grampians National Park has now burned up 55,000 hectares of bushland. They have had fire threatened areas around Halls Gap, Moyston and Pomonol over the last couple of weeks and it is continuing through today.

Back in February 2024 there was a bushfire in the Mt Cole valley and Pomonal areas, which destroyed a number of homes and primary school in the town. Also a Grampians winery named Mountainside decided not to pick the 2024 vintage because of smoke taint. Thankfully other wineries in the Grampians reported they were not affected by that bushfire (Source - ABC News).

Everyone out there will be watching the bushfire season this summer very closely.

Wow what an insightful response Sean. No question our biggest concern is a loss of life and property (homes). It is also devastating when people's livelihoods are destroyed or damaged. Let's hope neither people, nor properties are affected here.

Based on AWRI's latest research, there is certainly a chance that the bushfires will cause smoke taint in the grapes in the region, depending where a vinyeard is located and how long the bushfire lasts.

[phillisc]

Had a mate pick up some wine for me today at Bests... comment was it was very smoky indeed. They have been very unlucky in the Grampians to have two significant fire events inside 12 months.
Cheers Craig