Labs running overtime testing wine grapes for smoke taint

“It’s incredibly important. People use these results to make a decision about whether to harvest or not. You might have a multimillion-dollar crop and you get one chance a year to pick it, and if this testing shows that the grapes are no good then you can’t harvest. If they harvested and then found out they’re no good, they’ve spent more money throwing good money after bad,” he said.

Grape testing is typically done a couple of weeks before harvest. This gives winemakers enough time to conduct a “bench fermentation”, and to taste the wine to check for signs of smoke.

“If the winemaker can taste smoke and then gets results from a lab like ours, they can compare those two things and it’s up to them to make a decision about whether they should harvest,” Mr Howell said.

One of the Hunter Valley’s best-known wine producers Tyrrell’s revealed last month it would not harvest most of its vineyards because of smoke taint.  “We are estimating a total crop loss of 80 per cent,” the company said, adding that the impact of smoke taint was not universal across the Hunter Valley.

The intensity of a fire and heat play a role in smoke taint, as does the “age of the smoke”.

Australian Wine Research Institute managing director Mark Krstic said smoke from recently combusted material carried a higher risk than smoke drifting onto a vineyard many days after a fire ignited.

The institute, a body owned and governed by the wine industry, tests for smoke taint at a facility in Adelaide. Dr Krstic estimated that about 1000 wine grape samples had been tested so far this season, between the two testing organisations.

“We expect a lot more to come through the door, up until probably the end of March and beyond,” he said.

Smoke from a bushfire burning on the western side of Wine Country Drive at North Rothbury, NSW, in November 2019.Credit:Marina Neil

The samples sent to the institute are double-sealed in plastic bags, which contain 500 grams of wine grapes.

Dr Krstic was cautious about discussing test results, but said “a lot of decisions” had been made by producers to not harvest their grapes in response to the smoke.

“There’s certainly been some smoke-affected stuff, we’re not trying to hide that. But I would say that it’s been encouraging, we’re seeing in a lot of regions that there’s certainly a lot of hope out there still, in terms of producers making good wines this year,” he said.

Dr Krstic said the lab had been open since the middle of December and his team had been working right through the Christmas/New Year period, and over weekends.

The industry is so sensitive to this issue that they’re very keen to make sure that no tainted wine makes it out into the market.

Dr Mark Krstic, managing director of the Australian Wine Research Institute

“We’re taking in a lot of grape samples at the moment, testing them, and then providing data back for them to make decisions about whether they pick the grapes, or leave the grapes on the vine,” Dr Krstic said.

“The industry is so sensitive to this issue that they’re very keen to make sure that no tainted wine makes it out into the market,” he said.

Dr Krstic said more and more examples of smoke taint had emerged around the world in recent years, after fires in places such as California and South Africa.

“We know a lot about it but there’s still a lot of research and development required to really get to the bottom of the problem, and understand how we then manage it, because it is a very complex problem from a chemistry perspective,” he said.

Mr Howell stressed the industry had not been uniformly affected by this summer’s devastating bushfires. While smoke taint can have a severe impact on individual vineyards and incomes, “from an overall point of view for the Australian wine industry, the volume is hardly likely to be affected, because the bulk of the vines are grown in inland areas that haven’t been affected by these fires”.

The institute’s technicians have recently started testing wine from the current vintage for smoke taint.

What is smoke taint and how do scientists test for it?


Bushfire smoke can taint wine because of the chemicals released into the atmosphere when woody material such as trees burn. The chemicals that can damage wine grapes are known as volatile phenols, which are released in a gaseous form and travel with the smoke.

Dr Krstic said volatile phenols can be absorbed by the berries. His lab examines 500 gram samples of wine grapes when undertaking testing. It can also test wine that has been produced.

All up, the berries are put through a 12-stage process during testing. Early on they are blended to be “homogenised” before they are subject to complex scientific testing.

“We have to extract the taint compounds out of those samples and we run two separate chemical analyses,” Dr Krstic said.

One analysis measures volatile phenols and the other measures sugar-bound compounds in the samples. All up, 13 compounds are quantified, some of which occur naturally in grapes, and these measurements are then compared to normal background levels of the compounds in grapes.

The testing process uses expensive equipment that in some cases costs hundreds of thousands of dollars.

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