Two stories dominate this week’s harvest report. The first is the
continuation of near perfect weather for harvest across eastern
Washington. The second is the potential threat of smoke from a number of
large wildfires. Let’s start there.

Due
to the long, warm dry spell this season, a series of large wildfires
are burning in eastern Washington and central and southern Idaho. Smoke
from these wildfires has created a haze over large areas of eastern
Washington. While most of Washington’s growing regions are far from the
flames, others are fairly close.
 

The
Wenatchee Complex fire has burned an estimated 42,000 square acres. For
perspective, this almost equals Washington’s total planted grape
acreage last year. The smoke from this complex of fires has been so
thick that it has been difficult to see from one side of Lake Chelan to the
other in the nearby town of Chelan, with the air quality called ‘hazardous’ by the Washington Department of Ecology.
While the flames are further away, other wildfires brought smoke to the
Walla Walla Valley last week, dropping ash in some vineyards. Areas of
the Yakima Valley have also been hazy with smoke noticeable in the air.

The
obvious question is will this smoke have any effect on the state’s
grape harvest? The answer is difficult to determine at this point,
although growers and winemakers remain hopeful that smoke taint – which
has affected wines in Australia and California in the last decade – will
not be an issue in any of the state’s growing regions.

Many
factors are involved in creating smoke taint in wines, including the
distance of the vineyard from the fire, the density of the smoke, and
the duration of the grape/vine contact with the smoke. Research has also
shown that the absorption of smoke related compounds differs across
grapes varieties, with some more susceptible than others. Unfortunately,
there isn’t currently a full understanding of the contribution of all
of these variables or even the full equation.

Washington State University’s Viticulture & Enology Research & Extension newsletter last weekend
stated, “We currently do not know…how long smoke from wildfires needs
to be present in vineyards before smoke taint becomes a problem.”
However, due to the smoke, WSU recommends harvesting, “sooner rather
than later.”

ETS Laboratories
cautions that, “Vines do not need to be exposed to thick smoke
to produce tainted wines.” They also note that it is impossible to taste
the grapes, or the fermenting juice, and determine if they are tainted
or not, saying, “There is strong evidence that smoke taint compounds
absorbed by vines are partly bound to glycosides, making them difficult
to detect through sensory evaluation of grapes (read ETS’ full statement
here).”

How do wines made from smoke tainted grapes ultimately present themselves? On a sensory level, according to Australia’s Vinessential Laboratory,
wines affected by smoke can have aromas and flavors described as
‘burnt’, ‘ashtray’, ‘charred,’ ‘salami,’ and ‘disinfectant.’ In the
laboratory, Guaiacol and 4 methylguaiacol (G and 4MG) are marker
compounds for smoke taint and are measured by Gas Chromatography Mass
Spectrometry. These compounds can be tested in grapes, fermented juice,
and finished wine.

Australian based Memstar notes,
however, that G and 4MG levels in grapes and juice are not reliable
predictors of smoke taint in wine, as these compounds are not in a free
form until after fermentation. Additionally, their concentration
increases over time in finished wine as they are released from their
bound form.

There are steps growers and winemakers can take to reduce the potential effects of smoke taint. According to the Center for Expertise in Smoke Research at the Victoria Department of Primary Industries,
smoke taint can be reduced by hand harvesting, chilling grapes, and
altering pressing methods. WSU recommends reducing skin contact time,
conducting whole cluster pressing, and separating free run and press
juice. They also note that some strains of yeast lessen the effects of
smoke taint, while some other forms of yeast exacerbate it (read the
entire newsletter here).

For wine affected by smoke taint, research has focused on trying to remove it by using fining agents (read an example here).
Reverse osmosis has also been used but research has shown that this is
only temporarily effective with the taint returning over time.

Ultimately,
it remains to be seen whether the smoke in eastern Washington will have
a significant effect – or even any effect – on any of the wines
produced in 2012. A number of wineries are currently testing the grapes
they have harvested thus far for any evidence of smoke taint. Notably,
some areas of eastern Washington experienced some clearing of the smoke
over the weekend with rain also falling in a few areas. Stay tuned.

Outside
of the smoke, the otherwise favorable weather has continued to ripen
grapes in the vineyard, and winemakers remain excited for what the 2012
vintage holds.

“We could not have asked for better weather through most of the year and September has been spectacular,” John Bigelow of JM Cellars
says. “My first pick last year was September 28th. My first pick this
year was September 10th (both were Sauvignon Blanc). After two years of
cool harvests I am seeing smiling faces in the vineyards.”

While
the last two years the grapes reached physiological ripeness and
winemakers waited for sugar accumulation, this year marks a return to
previous years with physiological ripeness lagging. “I think the biggest
challenge this fall will be to have patience as we see the sugars climb
and to pick when the grapes are physiologically ripe,” Bigelow says.
“We have picked only one red so far, and that is Ciel du Cheval Merlot.”
Bigelow says that he was originally planning to pick more grapes but
held off. “I initially had these (blocks) scheduled for last week, but
after tasting and running acids on the samples it was clear the vines
have more to give, and I am glad I waited.”

Meanwhile Sean Boyd of Woodinville Wine Cellars
agrees about the good weather, saying, “This last week has been ideal
as has the last ten to twelve weeks or so.” Boyd says that he expects
harvest to continue for him into the third week of October assuming the
weather holds.

Josh Lawrence of Lawrence Vineyard and Gård Vintners
says of the vintage, “So far we’ve been very happy with the steady
maturation of the grapes and are thrilled to start harvest at a much
closer to average date, considering the struggles of the last two
seasons. As with many vineyards in the state, we are seeing significant
jumps in sugars while the acids are hanging in there nicely.”

Meanwhile Wade Wolfe, of Thurston Wolfe,
says of the growing season, “From a heat unit prospective, the season
has been near ‘normal’, though we had two notable climatic events that
have distinguished this year. The first was an unusually cool and damp
June that set grape development somewhat behind but did not appear to
have caused any adverse disease issues. The second was a hot spell in
mid July that was not unusual in its heat, but it was extremely humid
and was accompanied by severe thunderstorms and hail that caused
localized damage to vineyards and other crops. Since those two events,
the season has been near ideal for vine and fruit development.”

Wolfe,
who sources most of his fruit from vineyards in the Horse Heaven Hills
and Yakima Valley says, “With the warm, sunny days and cool nights
during September, sugars have been climbing rapidly while acids are
remaining relatively high. We are already seeing higher sugars by mid
September than we saw at the end of October during the last two seasons,
which were unusually cool.”

Wolfe
says of the smoke in eastern Washington in the areas that he works
with, “At current levels, though hazy and somewhat uncomfortable for
humans, I do not think it is concentrated enough to result in smoke
taint in the wines.”

Read previous harvest updates here. Satellite image from National Aeronautics and Space Administration. Picture of smoke on Lake Chelan courtesy of Chelan Estate Winery.

* * *

See information on the Washington State Growing Degree Days here.

See monthly forecast for Yakima Valley (Sunnyside), Red Mountain (Benton City), Walla Walla, Paterson, and Mattawa.

The
information in the table below is aggregated from personal
correspondence with growers and winemakers, as well as information
posted on Twitter and Facebook. It is not intended to be comprehensive
but rather is intended as a snapshot of what is going on around the
state. If you wish to send data for your grapes or vineyards (or correct
any of the information below), please email me at [email protected], leave a comment here, or leave a comment on the WWR Facebook page.