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Newcastle Herald
 
22 February 2020 | Newcastle Herald

The 2020 Hunter Valley wine vintage has been full of climate-related challenges

Hard season: Broke winegrower and winemaker Andrew Margan in December 2019. "Our crop is down by at least 50 per cent compared to 2018," he says. Picture: Max Mason-Hubers
 

Historically, rain comes standard at this time of year; it's the spur of the old Hunter wine-growing joke - if you can make great wine in the Hunter, you can make it anywhere. The drought, however, has really taken its toll on the winegrowers and their vineyards in Wine Country. Four consecutive vintages without any significant rainfall, made worse by persistent high temperatures and recurrent extreme-heat events; vines blistering by day and baking by night.

"This year, the sub-soil moisture has been completely depleted. Even with irrigation, the vines just struggle to ripen when day time temperatures get above 40C," viticulturist Liz Riley says. "The drought alone has seen average yields decrease anywhere between 40 per cent and 60 per cent."

Sadly, a drought is not as immediately dramatic as a bushfire. Fires get all the headlines.

"The fires came right down both sides of the valley, you could hardly see or breathe. The smoke was so thick it stung your eyes and made your throat sore. It went on for weeks and weeks," recounts winegrower Rod Windrim of Krinklewood Vineyard, near Broke.

The Broke-Fordwich sub-region was the worst affected by the bushfires burning nearby in the Yengo National Park and Corrabare State Forest.

"Thankfully, the vineyard wasn't burnt out, and our house and the fences weren't damaged, either. All we lost was this year's vintage," Windrim says, stoically.

Smoke haze had been visible in the air above the Hunter Valley since late October 2019, when out-of-control bushfires burned to the north, near Port Macquarie. This was only the beginning. As the summer season approached, large fires began burning all around the region, to the north, south, and west of Wine Country.

The subsequent smoke haze got thicker and thicker, heavier and heavier, drifting dangerously and aimlessly on the wind, draining down the slopes of the Brokenback range and encompassing vineyards right throughout the valley.

Still, the winegrowers didn't panic, because the vines hadn't hit veraison, yet. Veraison is the onset of ripening, when the colour of the grape bunch changes. A visual indication that the fruit is almost ready to harvest.

Early enquiries were made about the effect the smoke would have, but it was too soon to tell. The effects of smoke exposure to grapevines varies depending on its stages of growth and development. The most critical stage for potential smoke ingress in grapevines is during and after veraison, when sugars increase and grapes get riper.

"Smoke-taint compounds are made up of volatile phenols that permeate the skin of the grapes and bind to the sugars where they stay and accumulate. The more smoke the grapes are exposed to, the more phenols can bind to the sugars and accumulate in the grapes," says La Trobe University professor and smoke-taint researcher, Dr Ian Porter. "You need to get above a certain threshold of phenol compounds in the grapes to end up with a noticeable sensory taint in wine."

Smoke-taint can manifest itself anywhere between the pleasant smell of bacon to the filthy taste of a used ashtray. It all depends. The science of smoke-taint is still so new. What researchers, like Porter, do know is that the constitution of the smoke particulates - the composition and various levels of specific phenols in the smoke in the air - determines the severity of smoke-taint.

Dr Porter makes it very clear: "It's not wise to dumb it down to just smoke presence equals smoke-taint, because it's not that simple."

"Grape variety, moisture levels, UV radiation, wind direction, geography, topography and distance can all have a variable effect. People think it's just a matter of measuring smoke and assuming that any levels above 100 [g/kg, micrograms per kilogram] will be detrimental. It's just not that simple," Porter explains.

While the smog of millions of hectares of burnt out bush from beyond the Brokenback hung menacingly in the air, nervous winemakers sent off grape samples to the Australian Wine Research Institute (AWRI) as the start of harvest drew near. Under 100g/kg was OK, but, obviously, 30 is better than 90.

Winemakers performed micro-ferments - micro-batch winemaking - to verify the presence or absence of smoke-taint in their grapes. Red wine ferments should show higher signs of taint than white wine ferments, because of the grape skin contact and maceration required to extract colour, which can also extract any volatile phenols.

Despite the mitigating benefits of the irrigation network, which draws water from the Hunter River and distributes it over 500km2 to vineyard properties throughout Wine Country, the ongoing lack of rainfall over the last few years has severely impacted vineyard yields.

"Last year we were down about 30 per cent. This year we're down another 20 per cent. So, our crop is down by at least 50 per cent compared to 2018," Broke-Fordwich winegrower Andrew Margan says. "We have irrigation, which helps a lot, and the vines are relatively healthy. The problem is that the vines set their buds for the next vintage in November, and we've just had one of the driest November's on record. I can't see a lot of fruit being set for next year, unless we get some really decent rain between now and then."

The Hunter Valley has always had a reputation for being an extremely difficult region to grow grapes and make wine. The elements have always been against the region's winegrowers. Rain and hail are typically to blame, and fires have burned before. Most recently in '03, and before that, back in '68, when bushfires ravaged parts of Pokolbin, destroying vineyards, wineries, and other infrastructure.

"I remember there was a ring of fire around the ridge of the mountain, all the way around," Bruce Tyrrell recalls. "I was just a boy, but I remember everything was black... the fire just burnt everything that stood in its way. Of course, in those days, no one knew what smoke-taint was, so it was never discussed."

While it's clear that something has changed, in many ways the challenge of a vintage like 2020 is nothing new. As the oldest continually producing wine region in Australia, the people of the Hunter have a strong culture of cooperation, and a long history supporting and assisting one another through difficult times, such as this. Like all of us, they have an obligation to endure. To struggle against the elements, and any other challenges that beset them as wine producers of one of the world's greatest wine regions.

As Max Lake of Lake's Folly once wrote... 'where wine is easy to grow, it is seldom superb'.

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