Many vineyards in these regions have been affected by the recent bush fires directly and indirectly.
Although a winery may have suffered no fire damage, the blanket of
smoke that was its legacy has caused nightmares for many in the wine industry, thanks to what is known as “smoke taint”.
Vignerons watched the smoke linger over their ripening fruit for many days and even weeks.
The entire 2020 crop has been lost in some parts of Hunter
Valley and Adelaide Hills wine regions, while many growers are picking only a
fraction of their fruit.Bush fire smoke can taint wine as a result of the chemicals released into the atmosphere when woody material like trees burn. These chemicals that can damage wine grapes are known as volatile phenols. They are released in a gaseous form and travel with the smoke.
These volatile phenols can be absorbed by the grape berries.
When fresh, heavy smoke lands on the outside of the grape, the phenol compounds get into the skin but not the flesh.
However it’s a one-season thing. Next season the vines are fine.
Samples of wine grapes as well as the resultant wine (bench ferment) made from them can be tested for taint.
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.
The taint compounds are extracted out of the samples and subjected the two separate chemical analyses.
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 results of these tests provide a guide to the grower and the winery whether to harvest or not.
What with the drought and the bush fire in our area this season it appears that I made a good decision to cease my wine growing activities.
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