When Life Gives You Volcanoes, Make Wine

As Iceland’s volcano continues to emit smoke and lava – albeit in more modest amounts – we’ve learned that volcanic ash is apparently bad for airplanes and air travelers. The good news is that volcanic soil seems to be quite good for wine.

Throughout the Iceland’s “erupting” news, I couldn’t help but recall a geologist friend’s comments about volcanoes and wines after he returned from Cape Verde. He had traveled to a remote island with an impressive volcanic landscape, including Cha das Caldeiras, a volcanic plane. “From the (only) town on the island it takes you many hours to drive to Cha das Caldeiras,” said Professor Falk Amelung from the University of Miami in a recent e-mail. “There was nothing there other than lava and…vineyards. At least that’s the way I remember it!”

What’s in a soil?
Many of our favorite wine regions – Napa Valley, Chile, France, Germany, Italy, New Zealand – benefit from volcanic soils that include mineral-rich ingredients like basalt, pumice, perlite, jory and tufa. From glassy basalt that is rich in calcium, iron and magnesium to light, powdery perlite, these volcanic soil components vary in quantity and mineral composition.

“Minerals that come out of volcanoes are, by definition, stable at high temperatures,” said Professor Tim Dixon, University of Miami marine geologist and oenophile. “Upon eruption, they are rapidly chilled to glass, so the minerals are in a metastable state. Hence, they can rapidly break down – quick in a geologic sense, which means tens to hundreds of years. Ultimately, this process releases potash and phosphate, two critical nutrients normally in short supply.” In other words, volcanic soil makes for good soil chemistry.

Geologist colleague, also at the University of Miami, Shimon Wdowinski adds that these soils’ iron and magnesium could also be important. Volcanologists from University of California-Santa Barbara credit mineral-rich volcanic soils, too, noting that many people will risk heavy ash, lava flows and unbelievable damage to grow crops and raise livestock in these potentially dangerous areas because they are so bountiful. For example, except for the volcanic area near Naples, farming in southern Italy is difficult because of the prevalent limestone. Naples, however, has Mt. Vesuvius, and its two eruptions 35,000 and 12,000 years ago left mineral-rich soil that still is considered Italy’s best agricultural land.

According to Jeff Cox in The Wine News, the older, but not necessarily most dominant theory on volcanic soil’s benefits to wine, however, has to do with drainage. “For many years, the conventional wisdom, perpetuated by UC-Davis teachings, was that a soil’s drainage capacity, rather than some ineffable nutrient, had the biggest influence on the resulting quality of a wine.”

Professor Dixon also noted that volcanic soils provide important drainage. “Grape vines hate ” wet feet,” and volcanic terrains are usually sloped, hence drainage is good.” Winemakers will quickly tout the benefits of struggling vines that have to dig deep for their water and mineral sources, establishing stronger root systems in the process that make for heartier plants and fruit that is less fleshy and more concentrated in flavor.

The Santa Barbara volcanologists note yet another reason for volcanic soil’s benefits: its reaction to the sun: heat from the sun releases key elements from the rocks, making them accessible to the plants within. “Volcanic rocks make some of the best soils on earth because they… have a wide variety of common elements and are readily chemically separated into elemental components.”

Terroir, terroir, terroir
Though terroir sounds a lot like terrain, the French say it is much more than the ground and soil—it’s about the interconnectedness of all elements that ultimately produce great wines. It’s fascinating to see areas like the Mosel River Valley and Pfalz regions of Germany, that don’t seem to have any active volcanoes these days but still benefit from volcanic soil that remains to produce vibrant Riesling and Gewurztraminer.

Likewise, according to Cox, Napa Valley has an age-old connection. “Beginning about four or five million years ago, Napa Valley was a region of active volcanism. This ancient volcanic rock comes to the surface today on the lower slopes on either side of the valley.”

According to the Santa Barbara volcanologists, “after the Mt. St. Helens eruption in 1980, people who were living downwind from the eruption were concerned that the ash that fell would be detrimental to the agricultural farmlands of eastern Washington. This concern was countered by a group of knowledgeable earth scientists. Volcanic ash can be considered as a time-release capsule, rich in nutrients.”

While geologists know generally how volcanic ash or soil help better winemaking, it is hardly the only factor. So many variables play into producing great wine that winemakers seem to be able to rely on skill, experience and science only so much. Sometimes, they also need a little luck or magic.