Suds and Soil

Millions of years worth of geology — in the form of volcanoes, tectonic shifts and massive flooding — created the fertile soils of what is now the Dundee Hills.

By Mark Stock

On Feb, 4, Portland State University Geology professor Scott Burns lectured before a standing-room-only crowd at Portland’s Bagdad Theater. OMSI’s Science Pub attendees, pausing now and again to sip McMenamins Terminator Stout or Black Rabbit Red, witnessed a man possessed; so fastened to the field and the state of Oregon one couldn’t help but root for things like thunder eggs, trilobites, and calderas by the end of the evening.

Burns, an avid wine enthusiast, holds a Ph.D. in Geology from the University of Colorado. He speaks with the near-frantic, wide-eyed wonder of a child on his first trip to the Grand Canyon. Because his trade involves time frames in the millions of years, it’s all the more impressive that Dr. Burns can bring facts down to earth — quite literally — and digestible to the non-scientific and scientific communities alike. Perhaps it was the geology-themed game of trivia that kicked off the evening. Perhaps it was Burns’ intoxicating enthusiasm. Either way, the mood was relaxing and the take away was highly educational.

Bouncing from region to region, Burns dug through the deep and varied history of Oregon soil and its subsequent topography. He offered glimpses of unusual phenomena, such as Fort Rock in Southern Oregon’s Lake County; it’s a ring of towering rock formed by an ancient explosion involving groundwater and lava, or a maar volcano. And while most of the territory the professor covered was rural, Burns took a special liking to Portland and the surrounding Willamette Valley, sighting the great Missoula Floods and their effect on wine.

“Imagine a lake three times the depth of the Space Needle,” he said, barely pausing long enough to sip his beer. He clicked through a slideshow that presented a hypothetical version of the Portland skyline, circa 14,000 years ago. A 400-foot water level drowned many of the buildings, settling well over the waist of the city’s tallest edifice, the 42-story US Bancorp Tower. These floods are responsible for transporting rich nutrients and sedimentary soils to the Willamette Valley floor and setting an elevation marker for the coveted Jory soil series, at roughly 350 feet and up.

Within Oregon’s most vinified Valley, Burns tends toward the northern stretch. Here, three major soil types (Jory, Willakenzie, Woodburn) produce world-class Pinot Noir. According to Burns, this is the best place in the world to taste differences in terroir. Examining something as tangible and relatively immediate as wine is an enlightening way to understand something as long-handed and complex as regional geology. One sip can send a taster on a Magic School Bus-like ride to the lava flows and tectonic movement of ions ago.

Another remarkable wine region, according to Burns, is the Gorge, where, within 20 miles, the climate jumps from cool to warm. The usual suspects, Pinot Noir and Pinot Gris, in and around Hood River give way to sun-worshipping varietals like Zinfandel and Cab and Merlot near The Dalles. Annual precipitation rates decrease by an inch per year every mile one drives east on I-84 from Hood River on.

“Twelve of the 16 essential elements for wine grapes come from the soil,” wrote Burns in an academic piece titled “The Importance of Soil and Geology in Tasting Terroir.” The term terroir is an oft-debated word in viticulture. Burns breaks it down as the “complex interaction of all of the physical aspects of the vineyard: geology, soils, climate, geomorphology and grapes.”

Burns is from the large and growing camp that believes soil makeup lends directly to flavor makeup in a wine. In fact, PSU will be researching the northern part of the valley extensively in about a year, employing a mass spectrometer to determine which elements and trace materials occur in both the soils and their resulting wines.

For now, all one has to do is taste a Pinot Noir of the same vintage from Willakenzie soil versus the same varietal grown in Jory. People grumble about what exactly it is they’re tasting, but there is no denying the differences in flavor. And, as Burns argues, it’s the result of much more than just the climate, winemaker, yeast strain or clone. It’s about the characteristics of the earth just beneath the surface, where the roots carve out their homes. And it’s about the massive events that made the soils what they are today.

Just don’t expect high scores from Burns during El Niño years. “About the only thing that happens during those years is a lot of erosion and bad wine,” he said, chuckling. 

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