By Andy Perdue   and Eric Degerman

It’s easy to think of Oregon as a wine monoculture.

Indeed, of the state’s 41,500 tons of wine grapes harvested in 2011, Pinot Noir accounted for 23,726 tons.

Yet, one of the true gems in Oregon is Riesling, the state’s No. 4 wine grape at 1,900 tons harvested in 2011. In total tonnage, it is far behind Pinot Gris but doesn’t trail Chardonnay by much.

In quality, however, Oregon Riesling can stand alongside some of the best in the United States, including examples from Washington, New York, Michigan and Idaho.

Perhaps the biggest issue with Riesling is the cost to produce it in Oregon. The cool Willamette Valley will not allow Riesling to grow more than 3 tons per acre in a typical year — half of what vines can handle in the arid Columbia Valley of Washington. Yet the price per ton for Riesling is about the same in both states, but in Oregon, it fetches half the price per ton as Chardonnay.

The low price per ton for one of the most noble grapes in the wine world discourages growers from expanding plantings because they can make more harvesting Chardonnay, Viognier and Pinot Gris.

In recent weeks, we have tasted several world-class examples of Oregon Riesling. Ask for these at your favorite wine merchant or contact the wineries directly.

• Argyle Winery 2011 Riesling, Eola-Amity Hills, $18: Nate Klostermann has taken over winemaking at this longtime bubble house. Aromas of fresh-cut apple, sweet Bartlett pear, cantaloupe and clove give way to Honeycrisp apple flavors. While the residual sugar sits at 1.3 percent, the winery slots this on the dry edge of the scale because of its broad delivery of acidity that brings brightness and just a touch of spritziness.

• Stoller Family Estate 2012 Riesling, Dundee Hills, $25: Winemaker Melissa Burr obviously knows this noble German grape. She created a wine with aromas of Gala apple, baked pineapple, pumpkin pie spice, lemon, butterscotch and sliced celery. The palate brings fresh-squeezed orange juice, tangerine and Asian pear. Its abundant acidity of lime creates great length and combined with its bone-dry approach of 0.4 percent residual sugar makes it reminiscent of an Aussie Riesling.

• Penner-Ash Wine Cellars 2012 Riesling, Willamette Valley, $20: Lynn Penner-Ash is one of Oregon’s longest-tenured and most talented winemakers. This gorgeous Riesling opens with aromas of jasmine, lime and a whisper of basil, followed by flavors of lemon chiffon and bright apple. Piercing acidity is the highlight of this top-shelf effort.

• Elk Cove Vineyards 2011 Estate Riesling, Willamette Valley, $19: The nose is full of apricot marmalade, baked pineapple and poached apple with clove and cinnamon. The palate turns to Bosc pear and Gala apple flavors with a big burst of lemony acidity that provides length. The residual sugar settled out at 0.8 percent.

• Brooks Wines 2010 Ara Riesling, Willamette Valley, $25: There’s a sense of baked pineapple, poached pear, apricot, cloves and oiliness in the aromas, yet the palate is dry and dramatic. Flavors feature Asian pear and the second-cut of fresh pineapple, backed by bold acidity with overtones of grapefruit and apple. The finish carries classic slate qualities.

• Anne Amie Vineyards 2012 Estate Dry Riesling, Yamhill-Carlton, $20: A whiff brings up huge clove notes with lychee, peach, apricot, pear and pineapple. Its approach is crisp and dry with Granny Smith apple and Asian pear flavors, backed by a refreshing tiny dash of spritzy acidity than funnels into a classic finish of minerality.

• Union Wine Co. 2012 Kings Ridge Riesling, Willamette Valley, $13: Winemaker Greg Bauer has made a Riesling with aromas that unveil the purity of fruit. It opens with aromas of pear, apple, mineral and lime, followed by bright flavors of green apple, lemon zest and a hint of clove.

— Eric Degerman and Andy Perdue run Great Northwest Wine. Learn more about wine at www.greatnorthwestwine.com.