Royal Slope, Washington State's newest wine AVA
Photo courtesy of Stillwater Creek Vineyard

It’s an exciting time in the Northwest wine world! In June, two new American Viticultural Areas, or AVAs, were designated in Oregon and earlier this week Washington got one too. Let me introduce you to the brand new Royal Slope appellation.

Washington’s fifteenth AVA, Royal Slope is located wholly within the much larger Columbia Valley AVA. As you can see on the map below, it lays between the designated appellations of the Ancient Lakes and Wahluke Slope. Totaling over 156,000 acres, a 30-mile long east-west ridge named the Frenchman Hills offers miles of south-facing slopes that grape growers covet.

In fact, there are almost 2000 acres of vineyards planted, growing more than 21 different varietals. Red grapes found there are Cabernet franc, Cabernet sauvignon, Cinsault, Grenache, Malbec, Merlot, Mourvèdre, Petit verdot, Pinot noir, Sangiovese, Tempranillo, and Syrah. Whites are Chardonnay, Chenin blanc, Gewürztraminer, Pinot gris, Riesling, Roussanne, Sauvignon blanc, Semillon, and Viognier.

“The AVA is something of an island geographically that is surrounded on all four sides by very different lands,” explained Alan Busacca Ph.D., who co-wrote the AVA petition with Richard Rupp Ph.D. “North of the AVA are generally flatlands of the Quincy Valley with soils on shifting dune sands. To the east and south of the AVA, the landscape falls away into the harsh, basalt bedrock-dominated cliffs of Crab Creek Coulee gouged out by Missoula Floods, and on the west, the bedrock cliffs fall away steeply to the Columbia River.”

Most of the AVA is covered in loess soil, a windblown silt also found in Oregon’s Willamette Valley. Grape growers love loess soil since it drains well and is low in nutrients, helping to keep vine vigor in check. The Royal Slope AVA is considered arid, with an average yearly rainfall of under 8 inches. The grapevines need regular irrigation in order to grow in these conditions.

The average vineyard elevation in the Royal Slope AVA is about 1300 feet, more than twice as high as its southern neighbor Wahluke Slope. Both day and nighttime temperatures are cooler at that higher elevation, resulting in fruit with higher acid levels and thicker skins. Frost is less of a concern than in nearby AVAs with lower elevations closer to the valley floor.

The region is already well-known for producing excellent wines, including a Syrah sourced from Stoneridge Vineyard and made by Charles Smith that garnered 100 points from Wine Enthusiast. The Royal Slope AVA petition was formally submitted by the Royal Slope Wine Growers Association to the TTB in February 2017 and granted on September 2, 2020. As early as next year, you could begin seeing wine bottle labels sporting the Royal Slope AVA designation so keep your eyes peeled!

Click here to read about Oregon’s two most recent AVAs, Tualatin Hills and the Laurelwood District

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