Oregon Wine Depends on the Weather
Responding to Mother Nature's Fickle Gifts
by Jean Yates
What do winemakers and vineyard managers talk about when they get together? Chances are, the topic over a beer at Lumpy's (a tavern in Dundee frequented by lots of wine people) will be the weather.
There is no shortage of opinions- (seems like there's one for every person involved in the wine industry) - about the weather and its effects on the vintage. In an area of the world where every vintage has the chance of being ruined by rain, and where the vagarities of the weather can change a vintage from stellar to problematic in the course of week of rain or heat, the weather is disected, diced, graphed, and sworn at depending on the situation.
Has the climate changed in Oregon? Is it global warming? Or are we just in a cycle of warmer years like those seen back in the 20th century? How do you protect grapes from heat? Is harvest going to be earlier in the fall? How does the winemaker react to weather changes- heat spikes and earlier spring warmth and more dry hot weather?
Looking at Sokol Blosser's Estate vineyard on October 20, 2003, (below) you'd feel sure that the climate is warming. An exceptionally hot fall led to an early harvest.
Sokol Blosser Vineyard - October 2003
It's Getting Warmer
Oregon's Willamette Valley has historically been a very wet place to live, with weeks of non-stop rain in the winter and summers of rainy picnics, the Fourth of July traditionally celebrated indoors, watching the rain rather than fireworks. But over the last ten years, rather than cold wet summers, Oregonians have experienced hotter, dryer ones. Or at least that's the perception.
Oregon weather has contributed to a string of great vintages since 1998. Where a good harvest used to be defined as "the grapes ripened", extra sunshine and heat of the last few vintages produced very high quality grapes harvested almost at leisure, without the pressure of cool, rainy weather potentially ruining the harvest.
From 1998 through 2007, high temperatures recorded over 100 years were routinely broken. Unseasonally warm and dry weather for Oregon wine country became the norm. Oregon's temperate rain forest, the Willamette Valley, felt more like California.
Managing Vineyards for Weather
Oregon's wine industry is only about 40 years old. There was a lot to learn about growing wine grapes in this marginal region, and slow, painful experimentation has resulted in many improvements and changes that have improved grape flavor and quality.
Many of the methods used to adapt to the weather in Oregon are based on the assumption that there will not be enough heat and sunshine, and that everything that can be done to ripen the grapes must be done. More recently, methods to protect grapes from the sun and drought have become important to consider. The table below shows six aspects of grape growing and the ways that the winemaker adapts viticultural practices to the weather conditions.
Cool Wet Weather |
Hotter, Dryer Weather |
|
| Canopy | Leaf removal over grapes
to increase sun exposure- pull off the leaves and open
up the canopy to light and air- try to allow breezes into
the canopy to limit mold |
Leaves are left to shade
west facing grapes to prevent sun damage, less vigorous
thinning required, maybe wait later to thin leaves in case
of heat spike. |
| Disease | Mold from harvesting wet
grapes (rain during harvest) |
Less mold problems, but lots
of fruit sorting to avoid "sunstroke" fruit and
uneven cluster development. Might Phylloxera get worse
with warmer climate? |
| Irrigation | What? Dry farming was the
norm- there was so much rain- why irrigate? Yes, irrigate
young vines the first year, but after that, not needed..... |
But now drip irrigation is
necesary not just for the first year after grape vines
are planted, but for adult plants on west slopes and during
heat spikes. Or so some say, while others say irrigation
results in boring, homogeneous flavors. |
| Cropping Back | Remove all extra grape clusters early, give the few left on the vine the best chance to ripen. Keep crop levels very low to get ripeness and flavor. | Three or more lighter crop-backs may be needed so if the heat spikes, there are extra clusters to remove to adjust for high brix. More clusters may be left to ripen in hotter climate. |
| Planting Space, Rootstock & Clones |
Early vineyards were planted with more space between rows, self rooted or on vigorous root stock, and clones were from California's hotter climate. | Plant narrow densely spaced vineyards to early ripening Dijon clones 113, 114,115, 667, and 777. Use less vigorous root stocks to harvest earlier. |
| Harvest | Try to get the grapes in before the rains set in, usually mid to late October for Pinot noir. October 10 is often first day of Pinot noir harvest. | 2004 harvest could be the earliest ever, 2003 harvest started around September 10 because Brix levels were so high. |
According
to Jim Bernau, Founder and President of Willamette Valley Vineyards,
(pictured at right) a series of weather changes have re-written the rules
for Oregon winemaking.
"In the next ten years, I wouldn't be surprised if you see Willamette Valley wineries planting and successfully harvesting varieties of grapes that we could never ripen when I started growing grapes 30 years ago" he said.
Bernau founded Willamette Valley Vineyards 30 years ago, clearing the ground and planting wine grapes, and he started a weather journal that shows him the changes in the weather over the years.
"The last eight vintages in Oregon have been a solid string of the best ever, all for different reasons, related to the changing weather." he states.
""Where grape growing issues ten years ago centered on getting grapes to ripen, and avoiding mold from cool wet days during harvest, now the issues are water availability for irrigating, and protecting grapes from "sunstroke", a condition where over exposure to the sun makes the grape stop maturing and it stays small and green in the cluster. "
He sees "bud break" - the moment when the leaf first shows through the brown bud on the grape vine- about ten days early than it was in the 1990's. While late spring frosts used to frequently damage the crop, they are now rare. An early start to the growing season means an early harvest. And every day counts at harvest, where ten days can mean the difference between sunny, dry days, and the onset of Oregon's cold, wet winter weather.
Irrigation-Does Hotter Weather Mean It's Time to Water?
Perhaps few aspects of grape growing
provoke more vigorously held opinions than the use of drip irrigation
on wine grapes. Pinot noir is made from "dry farmed" grapes in Burgundy. The arguements for irrigation and against have vehement advocates on both sides.
Michael Etzel, winemaker and co-owner of Beaux Freres, says that irrigation is fine for inexpensive wines made by companies with big vineyards.
But, says Michael, "the glories and greats are not irrigated. How many 95 point Pinot noirs are irrigated? Not many, if any. If you want the essence of the site and a reflection in the wine of the growing year's characteristics, you cannot irrigate. Drip irrigation is like McDonalds- predictable, with no surprises. Dry farmed grapes reflect the authenticity of the site and the vintage. There is more variability between vintages, but to the serious wine collector, this authenticity is vital."
Gary Andrus, founder and former winemaker for Archery Summit, and currently owner and winemaker at Gypsy Dancer, comments:
"When you are planting in the densities that I started in New Zealand- (meter by meter or meter by 1.4 meters), irrigation is needed until the first crop. The competition between vines planted at such high density for water and nutrients, naturally devigours the plants. This is a good thing because it makes the berries smaller and the flavors more intense.
Gary continued: "However,
irrigation is needed for more than the first year because of
the competition for water and nutrients between vines.
This competition between plants increases during
heat spikes and
results in a need for supplemental water. And, regarding heat
spikes, the ability to level the growing
period by applying water when the
temperatures exceed 92 degrees is crucial to the proper ripening
of the vine.
When the temperature exceeds 92 to 93 degrees for several days,
the plants start to shut down and the carbohydrates start to
return to the roots."
"When heat and drought continue for several days, a plant sort of thinks it is going to die and needs to protect itself for the future by shutting down. Resulting in wilting, yellowing of leaves, just like in house plants you do not water. "
"The problem is that if grape vines do not receive water during say, August, and the plants have to wait for three to four weeks through lots of heat, the plant shuts down. Then it rains and the plants say, finally, lets grow again."
"So what
is the problem? Well the chemical that signals the plant to
start growing again, which comes up the plant from the roots,
makes the fruit taste like green beans or white pepper. So if
you can't irrigate when needed and then harvest within two weeks
the Pinot
will taste like canned green beans, very vegetal. Further, if
the plants shuts down, phenolic development is impeded
in the skins and stems just like with sun burn. So you get immature
skins where the flavors and tannins come from, but high sugar."
In summary, Gary states: "Water lets you manage the growing season,
and because you have it does not mean you use it. Better to have
the water and not need it than to not have it and need it. "
