The Willamette Valley, stretching from the Columbia River in Portland, south 150 miles to Eugene, covers 5,200 square miles and 3.3 million acres in Oregon's northwest region. Approved as an appellation in 1984, Willamette Valley is home to most of the 395 Oregon wineries. The expansive Willamette Valley with elevation, soil, climate and topography variations was difficult to characterize. The sub-appellations were conceived primarily to bring more definition and identity to the specific sub-regions of the Willamette Valley.
History Modern winemaking in the Willamette Valley dates back 40 years to three rogue winemakers with the belief that Oregon was the ideal place to grow cool-climate grapes. Their UC Davis peers scoffed at their vision, but David Lett, Charles Coury and Dick Erath separately made their mark by planting wine grapes, specifically, Pinot noir, in the north Willamette Valley. Within a decade, other notable winemakers followed and the world took notice of Oregon wine when David Lett's Eyrie Vineyard Pinot noir topped France's best labels in a tasting. Climate The Willamette Valley is relatively mild throughout the year, with cool, wet winters and warm, dry summers. With the Pacific Ocean only 40 miles to the west, the Willamette Valley enjoys the cooling effects of the evening summer marine breezes. The warm days and cool nights allow for slow ripening with expressive flavor development while retaining natural acidity.
Soils The Willamette Valley is an old volcanic and sedimentary seabed that has been overlaid with gravel, silt, rock and boulders brought by the Missoula Floods from Montana and Washington between 10,000 and 15,00 years ago. Found above 200' in elevation, the red volcanic Jory soil is the most common soil in the valley. Below 200' elevation is primarily sedimentary based soil.
Topography The Willamette Valley is protected by the Coast Range to the west, the Cascades to the east and a series of hill chains to the north. Its namesake, the Willamette River, runs through its heart meeting with the Columbia River near Portland.
Dundee Hills AVA
Dundee Hills is a sub-appellation within the Willamette Valley located 28 miles southwest of Portland and 40 miles inland from the Pacific Ocean. Encompassing 6,490 acres, the Dundee Hills are protected from harsh weather conditions by the Chehalem Mountains to the north, the Coast Range to the west and the Cascade Mountains to the east. Because of this unique formation, vineyards of the Dundee Hills provide some of the most highly acclaimed Oregon wines.
Guadalupe Vineyard, the source of Siltstone Wines Guadalupe Vineyard Pinot noir and Pinot gris, is located on the west slope of the Dundee Hills at 450' elevation.
Climate The Coast Range to the west provides a rain shadow over the Dundee Hills, resulting in just 30 to 45 inches of annual precipitation, most of which falls in the winter months outside the growing season. The slopes protect against the fog and frost found on the valley floor.
Topography The Dundee Hills viticultural region consists of a single, continuous landmass that rises above the surrounding Willamette Valley floors and is defined by the 200' elevation line to the highest peak of 1,067'. Valleys and ridges dot the area resulting from aggressive ancient volcanic activity.
Dundee Hills
McMinnville AVA
Hyland Vineyard in the McMinnville AVA
The McMinnville AVA (American Viticulatural Area) lies due west of the town of McMinnville in the Coast Range Foothills of Yamhill County. This AVA is the most westerly of all Oregon AVAs and is geologically and climatically very different from any other in the Willamette Valley.
Hyland Vineyard is located in the McMinnville AVA and provides exquisite Pinot noir and Riesling fruit for Siltstone Wines.
Geology The soils in the McMinnville AVA are some of the most complex of any Oregon AVA with a combination of marine sedimentary soils and basalt. The soils are primarily uplifed marine sedimentary loams and silts, with alluvial overlays. The clay and silt loams average 20-40 inches in depth before reaching harder rock.
Climate The east and south facing slopes sit in a protected weather shadow of the Coast Range Mountains. Annual rainfall of 33 inches is lower than sites only 10 miles to the east. The foothills also protect from chilling winds that blow spring and fall.
