396 THE ADVOCATE
VOL. 76 PART 3 MAY 2018
In short, tests can be good indicators that smoke taint may be present, but
they are not a guarantee it’s not. Rick Davis, who dealt with smoke taint
after the 2008 fires in northern California, put it this way: “You don’t
know until you know.”2
As might be expected, smoke taint is more often an issue with red wines
that are crushed and fermented on their skins. With white wines, where generally
the grapes are crushed and then the juice is immediately pressed off
the skins, there is less exposure of the juice to the phenols present on the
skins. But as those phenols can penetrate the skins while the grapes are still
on the vine and enter the grape, there is still a risk. Dr. Usher mentioned that
some Australian research showed that about fifty per cent of smoke phenols
penetrated Viognier grapes in fire-affected areas. By contrast, Merlot grapes
in the same areas had only about one-third of the phenols penetrate.
Dr. Usher’s research involves a lot of visiting local wineries that have
been in proximity to fires and sampling the wines. While he admits that the
resultant findings can be somewhat anecdotal, he has noted that problems
show mostly with interface fires. For instance, with the Testalinden Creek
fire in the Oliver area in 2015, smoke taint showed in some adjacent vineyards.
It did not show in vineyards that were subject to generalized smoke
haze for extended periods where the fires were distant.
He also noted that, at least in the Okanagan, the grape most affected is
Cabernet Franc. Other varieties that have thin skins and should seem susceptible,
like Pinot Noir, have not been affected to any significant degree.
This accords with Australian research that smoke from recently burnt
woody materials will contain higher concentrations of free volatile phenols,
and thus have greater potential to cause smoke taint.3 UBC’s Wine Research
Centre is currently conducting research into bound phenolic compounds
and markers regional to B.C. that should assist local growers and wineries.
While the research to date has not fully isolated the causes of smoke taint
and determined methods of control, prevention or cure, the wine industry
has been generally fortunate that it remains a relatively limited problem.
For instance, at least so far, no instances of smoke taint have been reported
in the Okanagan or Similkameen from the weeks of smoke that enveloped
us in 2017. Meanwhile in California, where fires burned throughout the fall
and into winter, most of the harvest was complete before they began, and
while there was widespread devastation to homes and some wineries and
vineyards, there has again been little reported effect on wines.
Fortunately, we have had no wineries burn in B.C. since the fires of 2003,
when St. Hubertus in West Kelowna lost its winery and some of its vineyards
in the Okanagan Mountain Park fire. The winery was rebuilt and
vineyards replanted, and they thrive to this day.