Oregon wine regions: The Willamette Valley AVA

My immediately preceding post provided an overview of winemaking in Oregon.  This post, the first of a series that will cover the individual winegrowing regions within the state, provides insight into one of its most important wine regions, the Willamette Valley.

The Willamette Valley AVA is the largest of the Oregon AVAs, covering, as it does, 5200 square miles to include an area from the Columbia River in the north to the Calapooya Mountains just south of Eugene and bordered on the west and east by the Coast and Cascade Ranges, respectively.  Named for the river that bisects its 60-mile width for most of its 150 mile length, the valley is home to two-thirds of the state's wineries.

Willamette Valley has a maritime climate -- cool, wet winters and warm, dry summers -- a climate pattern which, according to willamettevalleyagriculture.com, allows for a longer growing season.  The valley is protected by the Coast range to its west and a series of hill chains to the north.  According to oregonvineyardland.com, valley climate is moderated by three openings in the Coast Range which provide gateways for the transit of cool air between the Pacific Ocean and the valley.  The opening between Lincoln City on the coast and Salem in the valley is named Van Duzer Corridor.  The remaining two (un-named) corridors run from Newport to Corvalis and Florence to Eugene, respectively.

Rainfall averages 40-45 inches/year with 50% of the precipitation occurring between December and February and very little occurring during the summer.

As shown in the figure below, the Willamette Valley soil profile was established over a very long time horizon beginning with the hardening of ancient lava flows over 50 million years ago and continuing to the most recent layers deposited within the last 15,000 years.

Source: Pinot Camp 2012 document

According to the Oregon Pinot Camp 2012 documentation, ",,, great Willamette Valley Pinot Noir grows on rocky hillsides facing south or southeast, at least 200 feet above sea level and avoiding cooler hilltop microclimates over 800 feet."  The document goes on to assert that these conditions generally occur on volcanic, marine sedimentary, or windblown (loess) soils.

When it was initially designated in 1984, the Willamette Valley AVA extended over 3.3 million acres.  Over the intervening years, the valley's viticulturists have been able to discern and communicate the existence of six unique terroirs within the broader AVA and these six have all been designated as AVAs.  The characteristics of these AVAs are highlighted in the table  and figure below.

Source: Compiled from oregonwines.com

There are a total of 610 vineyards on the 15,120 planted acres in the Willamette Valley AVA and these vineyards produced 29,425 tons of grapes in 2011 (USDA NASS, Oregon Field Office, nassusda.gov).  Yield per harvested acre in 2011 was 2.18, indicating additional upside production potential without harm to the quality of the region's wines.  Of the 2011 wine grape production, 75.7% was Pinot Noir, 18.5% Pinot Gris and 5% Chardonnay.  Negligible amounts of Cabernet Sauvignon, Merlot, Syrah, and White Riesling are also planted.

Based on the numbers, Pinot Noir is king in the Willamette Valley. But there is no ubiquitous Pinot Noir profile.  According to Oregon Pinot Camp 2012, depending on the soil type, a different profile will emerge: on volcanic soils, Willamette Valley Pinot Noir will accentuate "high-toned aromatics, red/blue fruits, baking spices, and soft, succulent tannins;"  on sedimentary soils, "blue/black fruit, earth tones, and ... heavier tannins;" and on loess, "mixed berry fruits, exotic spices, licorice, cedar" along with briary components and round tannins.

With all of the assets listed above, Willamette Valley AVA would not have been as successful as it has become without the people.  From the pioneers, to the ones who followed, to the viticulturists and owners plying the trade today, the valley has been characterized by a cooperative, learning, working relationship which should serve as a model to every up-and-coming wine region.


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