No grape variety is as reflective of climatic and site differences as Pinot noir. That is why it demands a cool climate to thrive and why small distance differences in the valley often yield wines of distinctively different character. General attributes that make the Willamette Valley suitable for cool climate grape growing include the protection afforded by the Cascade Mountains to the east, Coast Range mountains to the west and a series of lower hill chains to the extreme north of the valley. Almost all grape growing is done on lower hillsides, avoiding deeply fertile alluvial soils and cooler hilltop mesoclimates.
It is on these hillsides that Pinot noir uniqueness is found and where apparent families of wines urge distinctive American Viticultural Area identification. In 2002, a collaborative action of vineyards and wineries delineated and submitted to the TTB petitions to divide much of the northern part of the large Willamette Valley AVA into six more specific AVAs: Chehalem Mountains, Dundee Hills, Eola-Amity Hills, McMinnville, Ribbon Ridge, and Yamhill-Carlton.
Chehalem Mountains EST. 2006
The Chehalem Mountains AVA is a single uplifted landmass southwest of Portland in the northern Willamette Valley, extending 20 miles in length and 5 miles in breadth, stretching from southeast to northwest. It includes several discrete spurs, mountains and ridges, such as Ribbon Ridge and Parrott Mountain. The highest point within the Willamette Valley is the Chehalem Mountains’ Bald Peak (at 1,633 feet) which affects weather for the AVA and for adjoining grape growing hillsides. It is the geography and climate that differentiate this AVA from others. All three important hillside soil types are represented: basaltic, ocean sedimentary and loess (blown lake bed sediment), the predominant soil on the northern face of the Chehalem Mountains. Within the almost 70,000 acres of this AVA are over 1,600 acres of grapes, grown in over 100 vineyards, and 31 wineries.
The first grapes in the Willamette Valley were planted in the Dundee Hills. It remains the most densely planted locale in the valley and state. Within the 12,500 acres of this almost exclusively basaltic landmass that runs north-south and overlooks the Willamette River to the south and the Chehalem Valley to the north, more than 1,700 acres of grapes are planted in approximately 50 vineyards. It is approximately 30 miles to the southwest of Portland and 40 miles east of the Pacific Ocean, with protection from the ocean climate provided by the higher Coast Range of mountains.
Adjacent to the Willamette River, these hills are composed of the Eola Hills, straddling the 45th parallel on the southern end and the Amity Hills on the northern spur, constituting almost 40,000 acres on which more than 1,300 acres of grapes are planted. Two of the predominant influences on the characteristics of wines from the Eola Hills are shallow soils and the Van Duzer corridor. The soils of the Eola Hills contain predominantly volcanic basalt from ancient lava flows, combined with marine sedimentary rocks and/or alluvial deposits, making a generally much shallower and rockier set of well-drained soils which produce small grapes with great concentration. The Van Duzer corridor provides a break in the Coast Range that allows cool ocean winds to flow, dropping temperatures dramatically (especially during late summer afternoons), which helps to keep acids firm.
The McMinnville AVA of nearly 40,500 acres sits due west of Yamhill County’s seat, the city of McMinnville. It extends approximately 20 miles south-southwest toward the mouth of the Van Duzer corridor, Oregon’s lowest coast range pass to the Pacific Ocean. Encompassing the land above 200 feet and below 1,000 feet in elevation on the east and southeast slopes of these foothills of the coast-range mountains, the soils are primarily uplifted marine sedimentary loams and silts, with alluvial overlays and a base of uplifting basalt. The soils are uniquely shallow for winegrowing. The planted slopes sit in the protecting weather shadow of the Coast Range mountains, and rainfall is lower than on sites to the east. The primarily east- and south-facing sites take advantage of the drying winds from the Van Duzer corridor. Approximately 600 acres are currently planted here.
Ribbon Ridge is a very regular spur of ocean sediment uplift off the northwest end of the Chehalem Mountains, containing a relatively uniform 5 1/4 square miles (3,350 acres) of land. Approximately 500 acres are currently planted on the ridge, within 20 vineyards. The AVA is distinguished by uniform, unique ocean sedimentary soils and a geography that is protected climatically by the larger landmasses surrounding it. Paucity of aquifers forces most vineyards to be dry farmed. Ribbon Ridge is contained within the larger Chehalem Mountains AVA.
Willamette Valley EST. 1983
Concentrated grapegrowing in Oregon began here, with initial plantings in 1966 and ongoing vineyard growth in the intervening forty years adding over 10,000 acres, largely because of the benign but challenging cool climate and the protection of mountains on eastern and western boundaries—and, also largely because of one grape variety, Pinot noir. A large AVA of 3,438,000 acres (5372 square miles), running from Portland in the north to Eugene in the south, it includes rich alluvial soils on the valley floor, that are great for agriculture but inappropriate for high quality grapegrowing, and a selection of volcanic, loess and sedimentary soils on hillsides of varying mesoclimates.
To acknowledge the uniqueness of certain smaller growing hillsides inside the valley, AVA designation was requested for six areas in the northern valley, which contain sixty per-cent of the currently planted acreage of the Willamette Valley. All these new AVAs have minimum elevations around 200 feet; some also have a maximum of 1000 feet.
Yamhill-Carlton EST. 2005
North of McMinnville, the foothills of the Coast Range create an AVA of nearly 60,000 acres, centered around the hamlets of Carlton and Yamhill. Low ridges surround the two communities in a horseshoe shape, with the North Yamhill River coursing through nurseries, grain fields, orchards and more than 1,200 acres of vineyard. This pastoral northwest corner of Oregon’s Willamette Valley provides a unique set of growing conditions. The Coast Range to the west soars to nearly 3,500 feet (1,200m) establishing a rain shadow over the entire district. Additional protection is afforded by the Chehalem Mountains to the north and the Dundee Hills to the east. Importantly, the coarse-grained, ancient marine sediments native to the area are some of the oldest soils in the valley. These soils drain quickly, establishing a natural deficit-irrigation effect.