48. Volcanic Soils and the Character of Wine

Volcanic Soils and the Character of Wine

Mitchell Rabinowitz

Volcanic soils speak with contradiction. They are often poor in organic matter, yet rich in minerals. They drain quickly, but hold enough water in stone crevices to sustain vines through dry seasons. The wines they yield are often described as precise, saline, and structured. Yet in other places, the same soils give rise to wines that are broad, smoky, and texturally soft, with less drive and acidity. Volcanic influence is real, but elusive. It shifts with climate, elevation, ash composition, and the age of the eruption. That ambiguity is what makes it worth exploring.

Most vineyard soils are categorized by parent rock: granite, schist, limestone. These types help define the physical and chemical makeup of vineyard sites, influencing water retention, drainage, and nutrient availability. Volcanic soils belong in a category of their own not because of a single mineral profile, but because of the way they are formed. Rather than originating from slowly weathered rock, they result from violent, sudden geological events. They form as lava flows, ash deposits, or fragmented tuff that is later weathered into cultivatable ground. These materials originate from different phases of volcanic activity. Lava that cools quickly on the surface forms solid rock. Among these, basalt is the most common. It is a dense, dark stone high in iron and magnesium. Volcanic ash, by contrast, consists of fine, glassy particles released explosively into the air. When it settles and weathers, it creates light, porous soils or compresses into tuff, which is a type of rock formed from compacted volcanic ash. Although they differ in form, both basalt and ash contribute to the mineral and structural diversity of volcanic vineyards.

Geography plays a significant role. Some volcanic vineyards lie on island arcs such as Santorini, the Azores, and the Canaries, where ocean winds and sparse rainfall interact with dark, mineral-rich earth. Others sit inland on ancient calderas, which are large, collapsed volcanic chambers, like those found in Soave or Tokaj, where erosion has softened the surface but left the underlying mineral profile intact. Elevation often matters more than latitude. On volcanoes like Etna or Haleakalā, a difference of 800 meters can separate vines harvested in August from those picked in November.

Growers working these sites speak in practical terms. Volcanic soils warm early in spring, which can advance budbreak. They are often low in clay, so compaction is rarely an issue. However, they are also friable, meaning easily crumbled, and prone to erosion. They can challenge young vines with nutrient scarcity. Managing this requires not just knowledge of the soil, but an understanding of wind exposure, rainfall distribution, and how water moves across or through the slope. These choices in vineyard management directly influence the structure, energy, and clarity that many associate with volcanic wines.

Wines from volcanic terroir tend to show energy. That word, in this context, refers to the sensation of linearity, of mouthwatering brightness, of persistent texture that lingers through the finish. This is what tasters mean when they say a wine “moves” or “cuts.” While the acidity in these wines may not always be high, their defined shape and tension, what wine professionals call structure, create a sense of lift, or rising clarity on the palate.

Not every volcanic wine expresses this tension. Some are supple and broad. The difference often comes down to the age and type of volcanic material, the depth of the topsoil, and whether the vines are dry-farmed or irrigated. In areas like Sicily’s Faro or Chile’s Itata, older vines growing on deeply decomposed volcanic rock can produce wines with a gentler, more grounded structure. The influence of the soil may appear not in sharpness, but in restraint, or in a subtle note of smoke or crushed stone.

Trade fairs now group these wines together, implying their origin alone ensures uniqueness. This simplifies the story. What matters is not just that the soil is volcanic, but how it interacts with vine material, viticultural methods, and climate. The most compelling wines from these sites do not taste of lava. They taste of place. Volcanic origin provides the outline, but human understanding fills in the form.

Some winemakers are skeptical of this narrative. Certain volcanic plots, especially those dominated by compacted ash, can be infertile and unproductive. Others argue that mineral uptake in vines does not directly lead to mineral flavors in wine. This counterpoint matters, especially in light of the marketing emphasis placed on volcanic origin. What we describe as “minerality” may result more from acid balance and fermentation byproducts than from geology. Still, there is value in accumulated experience. Growers who have worked the same terraces for decades often notice how subtle changes in soil composition are reflected in the finished wine.

In the end, volcanic soils are not a shortcut to quality or a guarantee of style. They present a series of conditions. These conditions can produce wines of depth, clarity, and tension, or wines that are broader, darker, and more tactile. The contradiction at the heart of volcanic terroir lies in its range. The same ground that produces lean, linear wines in one location may yield supple, smoky wines in another. The soil is the bedrock, but it is the choices made above it — in farming, in fermentation, in aging — that shape the final expression.

But see also…

Also read: