December 2008 issue
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Oregon’s Willamette Valley: Islands of Terroir Ben Narasin
The cracks in the 2,000-foot dam began to form slowly at first, almost undetectably. Life carried on peacefully in the dry Willamette Valley below, as it had for eons. But the effect of the warming climate and 200 miles of rising water was finally too much; the explosive force as the dam gave way was “10 times the combined flow of all the rivers in the world,” according to the U.S. National Park Service. “This towering mass of water and ice literally shook the ground.”
Nothing could outrun the 65-mile-per-hour torrent. It lasted for two days. The flood ripped through the valley, following the path of volcanic flows millions of years before. When nature was exhausted, the valley was filled with 300 feet of soaking soil. All life was buried beneath, trapped between the Coast Range and the Cascade Mountains. Only the tips of the highest hills and sturdiest land masses remained, peeking out from the river of mud like dolphins cresting a calm sea.
Two states’ worth of glacial lake water, icy soil, and rock had washed down through the demolished ice dam. But this was not a modern catastrophe caused by global warming: this flood of earth occurred at the end of the last ice age, 15,000 years ago, and it created the rich base of topsoil that has made Oregon’s Willamette Valley a cornucopia of agriculture.
The Willamette Valley was born of water, fire, and ice. Originally a deep-sea floor, it was forced into the air by collisions of the earth’s tectonic plates below. The valley between two mountain ranges was then flooded with lava, leaving behind a basalt base. A combination of marine sediment and lava effluent now rises above the deep layer of topsoil that filled the 60-mile-wide valley during the glacial flood.
The valley floor’s alluvial soil is “paradise for agriculture,” says Pat Dudley, founder of Bethel Heights Vineyard, “for everything except wine grapes.” Some 250 crops grow in the Willamette Valley, but grapes are almost universally planted on the slopes. Dudley describes the valley as a “tub full of deep, rich soil with just the tops of the old soil sticking out.” Those islands of ancient soil have become islands of terroir.
Although the Willamette Valley American Viticultural Area was designated in 1983, its subappellations are much more recent. Yamhill-Carlton District, Ribbon Ridge, Dundee Hills, and McMinnville were recognized in 2005, and Chehalem Mountains and Eola-Amity Hills in 2006 (see box). There will likely be more AVAs as producers focus on distinct terroirs and lobby for their recognition.
According to the trade association Willamette Valley Wineries, the six new AVAs all have elevations of at least 200 feet, some rising as high as 1,000 feet. Nearly all the grape growing is done on the lower hillsides, avoiding both the fertile alluvial soils and the cooler hilltop microclimates. While the broader Willamette Valley AVA is home to two-thirds of Oregon’s wineries and the preponderance of its Pinot Noir vines, the subappellations now account for 60% of its plantings.
“The dominant characteristic overall is cool climate,” says Steve Baker, formerly with King Estate, which is located at the southern tip of the region. “It maintains that critical acidity that’s so important.” The Coastal Range protects the valley from maritime weather, but allows moderating sea breezes to penetrate through the Van Duzer Corridor. The Willamette River also contributes to the long, cool growing season.
Some areas are a bit warmer (Dundee Hills), others a bit cooler (Eola-Amity Hills). Some have more predominant volcanic substrates (Dundee and Eola-Amity), others more marine sediment (Yamhill-Carlton and Ribbon Ridge). One is a hodgepodge of soils (McMinnville), another is all loess (Chehalem Mountains). With that much variation in terroir and so brief a history of viticulture, it’s still difficult to define typical characteristics at a sub-AVA level.
“The Willamette Valley is huge when it comes to different microclimates, so I think we’re still trying to figure that out,” says Baker. “It’s in its infancy as far as the appellation system in Oregon. We just don’t have enough track record to recognize what’s going on.”
“Vintage trumps AVA. Winemaker style trumps AVA,” adds Dudley. We “just don’t think we have enough history yet.”
The Willamette Valley offers some advantages for growing cool-climate grape varieties that are not available to its southern neighbors. For example, 30º diurnal temperature shifts are not uncommon; summer daylight lasts an hour longer than in Napa; and grapes hang longer and develop more slowly, with harvest usually finishing about a month later than in California. Winemakers have traditionally tried to account for these circumstances by planting earlier-ripening rootstocks and clones.
Of course, such conditions provide the perfect environment for varietals that happen to be fashionable at the moment. Pinot Noir’s ascendancy has been a boon to the Willamette Valley; Pinot Gris, Chardonnay, and Riesling have benefited as well. “We’re long on Pinot Gris,” says Baker, although some producers have ignored the happy-go-lucky grape. “I think Pinot Gris is a cheap date,” remarks Doug Tunnell, founder of Brick House Vineyards, who focuses his production on Pinot Noir, Chardonnay, and a unique pet project, Gamay Noir (“poor man’s Pinot,” according to Tunnell).
Considering the region’s ever-expanding range of excellent single-vineyard, subappellation offerings; its continuing strength in Pinot Noir production; and its enticing selection of Burgundian white wines, especially Chardonnay, as well as some compelling specialty varietals, there may be another flood building in the Willamette Valley—a flood of exceptional wines.
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