Whilst it obviously doesn’t compare to the devastation experienced by so many during the recent bushfires, we were fully aware that the smoke haze that lingered through the Hilltops and neighbouring regions during the fires also posed a significant threat to our vineyards and our winemaking process this season. And unfortunately, we weren’t wrong!
For many local winemakers, such as ourselves, the smoke has had a devastating effect, penetrating our grapes and destroying 90% of our 2020 vintage. Yes they are our grapes in the photo, picked from the vine and lying useless on the ground.
How does smoke impact wine production?
Smoke from bushfires is made up of many chemical compounds and when the smoke sits on the skin of the grapes, the chemical compounds are absorbed by the grapes as they ripen. Then, when the grapes are crushed and begin to ferment, the smoke compounds are released into the wine.
Drinking smoke-tainted wines is very unpleasant. The wines can smell and taste like a campfire or an ashtray. They can even have a heavy chemical taste depending on the types of smoke compounds present. The wines also taste very dry and dusty. They can also be very bitter or acrid at the extreme level. Not something you would really want to share with your friends!.
The result of the smoke from the recent bushfires is that we and many other wine producers will not be making any wine from our 2020 vintage vineyards. We actually don’t remember a time when so many wineries, in the local and surrounding regions, including Murrumbateman and Canberra, have had to ‘write off’ an entire vintage.
To top it off, the hot weather and the smoke in the air this summer has also meant that numbers of visitors to wineries in these regions have also been down compared to this time in previous years. So, my friends, if you are a wine lover, then get along and support your favourite winery – Grove Estate Wines.
How are the grapes tested for smoke taint?
Grape testing is typically done a couple of weeks before harvest in a scientific laboratory. This gives winemakers enough time to conduct a “bench fermentation” and to taste the wine themselves to check for signs of smoke. If the winemaker can taste smoke and then also get results from a lab, they can compare those two things and it’s up to them to make a decision about whether they should harvest or not,
The grapes are sent to appropriate labs for testing. Generally 500 gram samples of wine grapes are examined and during testing the grapes are put through a 12-stage process. Early on in the testing they are blended to be “homogenised” before they are subject to complex scientific testing.
Smoke taint compound samples are extracted out of the grapes being tested, ready to undergo two separate chemical analyses. One analysis measures volatile phenols and the other measures sugar-bound compounds. All up, 13 compounds are identified and compared to normal background levels of the compounds found in unaffected grapes.