More info

Oregon Wine Board: 4640 SW Macadam Ave., Suite 240, Portland;, 503-228- 8337.

Washington Wine Commission: 1201 Western Ave., Suite 450, Seattle;, 206-326- 5760.

If you’re a serious wine drinker, you can’t just buy a glass or a bottle of wine and not care about its origin.

Is your pinot noir from Oregon’s Willamette Valley, or was it produced in California or France? Is that merlot a Walla Walla vintage, or were the grapes grown in the Applegate Valley, south of the Rogue River? Was your riesling made in Woodinville, Washington, near Seattle, by way of the Yakima Valley, or is it from Idaho’s Snake River Valley?

The characteristics of wine varietals are determined to a large degree by the terroir (the soil, topography and climate) in which they were grown. Grapes grown in any specific habitat are believed by wine experts to have qualities unique to that location, however small and remote it may be.

Such factors as elevation and aspect — the direction the slope faces to capture the sun — are important. The amount of rainfall and direct heat received, and in which seasons, are key elements to consider.

So is soil. Sandy soils, which retain heat, drain well and are more pest-resistant, produce soft wines with light acidity. Clay soils stay cooler and retain water, lending themselves to bold reds. Fine-grained, silt-rich soils retain both water and heat and tend to be especially successful if mixed with limestone, which produces sweeter grapes and drains well in cooler weather. The presence of gravel also contributes to drainage.

Oregon regions

There are nearly 700 wineries in Oregon. More than 500 of them are in the Willamette Valley, stretching over 120 miles south from the Portland area to Cottage Grove. The vast majority of these wineries specialize in pinot noir, a light-bodied red-wine grape that thrives in cooler-climate regions around the world.

Originally from France’s Burgundy region, pinot noir has done well in several growing regions of California and New Zealand, but perhaps nowhere in the past 50 years has it dominated an area’s production as it has done in Oregon’s Willamette Valley. According to the Oregon Wine Board, there are more than 19,000 acres of vineyards in this valley, and nearly 75 percent of them are planted with pinot noir. Pinot gris is a distant second place in the Willamette, followed by chardonnay, riesling and pinot blanc, all white grapes.

Grown predominantly on the gentle, east-facing slopes of the Coast Range, the pinot noir grape has fostered six terroir-specific American Viticultural Areas between Salem and Forest Grove — including the Eola Hills, McMinnville, Yamhill-Carlton, Dundee Hills, Ribbon Ridge and Chehalem Mountains. To connoisseurs, grapes from each of these AVAs have distinct characteristics.

Those who love heartier red wines may find what they are looking for elsewhere in the state. Southern Oregon, including the Rogue, Applegate and Umpqua valleys, has almost 150 wineries that produce dozens of varietals. With greater extremes of temperature and less rainfall than the Willamette Valley, this is one of the most diverse growing regions in the country.

Spanish-style tempranillo, pioneered in the Umpqua in the 1990s, is now a trademark grape for all of Southern Oregon. Bordeaux (cabernet, merlot, malbec, petit verdot) and Rhone (notably syrah and viognier) style wines do very well here.

There are about 30 wineries in the Columbia River Gorge, on either side of the river in both Oregon and Washington. Located primarily around Hood River, they extend east beyond The Dalles to the Maryhill, Washington, area. Production extends literally from A to Z — from albarino to zinfandel — with grapes like grenache and sauvignon blanc among the most popular.

The Snake River Valley region lies predominantly in western Idaho, especially south of Nampa and Caldwell, but there is a smattering of vineyard country in Oregon outside of Ontario and Baker City. Notable here are sweeter rieslings and chardonnays, merlots and syrahs.

Washington wines

The leading wine region north of California’s Napa and Sonoma valleys is the Columbia Valley of Washington. Covering a vast area that extends east of the Cascades from the Oregon border north to the Okanogan region — and including most of Washington’s nearly 900 wineries — it embraces the Yakima Valley growing region, the most prolific in the Northwest.

Yakima’s topsoil is wind-blown silt, or loess, that rests upon ancient flood soils of sandy loam. Cabernet sauvignon and merlot do especially well here, although they tend to be slightly lighter in color and more aromatic than their California counterparts. Mercer Wine Estates in Prosser is one of the best; its malbec and its Sharp Sisters Red Blend, a meeting of nine different grapes headed by merlot and syrah, are memorable.

The Yakima Valley is framed by several individual AVAs, including Horse Heaven Hills to its south, Rattlesnake Hills to its north, Naches Heights to its west and the narrow ridge of Snipes Mountain right in its heart. None of those is as notable as tiny Red Mountain, a steeply sloping, south-facing wedge between Benton City, at the east end of the valley, and West Richland, on the periphery of the Tri-Cities.

With a unique soil profile and microclimate — hot, dry summer days and cool evenings — Red Mountain is unique among Northwest growing areas. Its 4,000 acres are planted with just 600 acres of cabernet sauvignon, cabernet franc, merlot, syrah and sangiovese, all of which must be studiously irrigated, as the average annual rainfall is only 5 inches. These wines are known for their intense yet balanced berry flavors; cabernets by longtime growers such as Kiona Vineyards and Hedges Family Estates may fetch as much as 30 percent above market price.

Less than an hour’s drive east of Red Mountain is the Walla Walla Valley, whose intense summer heat has made it a favorite of syrah and merlot producers. There are more than 100 wineries in this area, which lapses into Oregon at the town of Milton-Freewater. A unique vineyard district on this border is “The Rocks,” an ancient river bed planted with syrah grapes by a small number of growers. The soil lends the wine a peppery character and rare minerality.

Elsewhere in Eastern Washington, vineyards on the arid Wahluke Slope north of Hanford produce many of the grapes for the region’s wineries. There’s a young but thriving wine industry near Wenatchee and on Lake Chelan. And Spokane is emerging as another center.

By far the greatest concentration of winery tasting rooms in the Northwest is in the northeast Seattle suburb of Woodinville. Ironically, the Puget Sound area itself is far too rainy to be successful in propagating grapes. So wineries pick and often press their grapes in Eastern Washington, then truck the fruit (or the juice) over the Cascades for production in Woodinville.

Chief among these is Chateau Ste. Michelle, Washington’s oldest winery, founded in 1954. The world’s top producer of riesling wines, including late-harvest “ice” varieties, it makes more than 2 million cases a year.

The bottom line is this: There’s a wine for everyone in the Pacific Northwest. The secret is in knowing exactly where to find it.

— John Gottberg Anderson specializes in Northwest wines. His column appears in GO! every other week. He also writes for our food section.