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Alto Piemonte and its Super Volcano: geology, soil, climate and winemaking
Alto Piemonte is the home of a geological phenomenon found nowhere else on Earth - the Super Volcano of the Sesia Val Grande Global UNESCO Geopark. Here, the magic of winemaking is intertwined with geological mysteries, complex soils and subalpine climate. Our mission is to display all of this in the flavors of our wines.
What is a «super» volcano and how did we discover it?
Super volcanoes are colossal calderas, massive depressions in the Earth's crust. Unlike craters, which are normally visible (as they are formed through an outward eruption of a volcano), a caldera is normally invisible to the eye. It is the result of an inward collapse of a volcano and it may extend for kilometers into the Earth. The formation of a caldera as a result of a volcanic eruption is a much greater phenomenon than the formation of a crater. This cataclysmic event is capable of altering climates and ecosystems significantly: it’s an extremely rare phenomenon, comparable to 250 atom bombs exploding at the same time, with less than 15 super volcanoes on our planet. The Valsesia Super Volcano is now fossilized (this means it is not active anymore). It started its activity approximately 300 million years ago and its most tremendous and final explosion occurred 280 million years ago, releasing something like 500 cubic kilometers of volcanic material and triggering the final collapse of the caldera. At the time, the continents had not drifted yet.
If a caldera extends towards the centre of the Earth and it is not usually visible on the surface, how did scientists notice it?
Fast forward about 40 million years ago, and this unique phenomenon becomes even more astonishing. During the formation of the Alps, the collision between the African and the European plates uplifted and tilted the super volcano by 90 degrees, bringing it to the surface and uplifting rocks which are normally 25-30 kilometers in depth towards the centre of the Earth.
Boca DOC and Gattinara DOCG are single village appellations which lie in the heart of such a unique and rare phenomenon; the Colline Novaresi DOC benefits from the very impressive aftereffects.
From a winemaking point of view this is so exciting: it means that the roots of our Nebbiolo vines dig through a unique and extremely rare, Unesco protected geo-site, which has one of the highest levels of geological complexity in the world. As winemakers, we like to simplify things a bit and explain it as follows: think of it as putting all the soil types you can think of into a gigantic natural shaker (remember… 500 cubic kilometers of stuff!!!), pouring the resulting very random mix of minerals in depth into our vineyards and feeding our vines with it (including some rocks which are normally 25-30 kilometers in depth towards the centre of the Earth). The consequences in the aromatic compounds can never be overstated
Who gets the credit for this discovery?
Until 2009, the locals kept wondering why certain visitors would regularly come and walk up and down the river Sesia (which devides Boca d.o.c. from Gattinara d.o.c.g.) with caver’s hammers. The river Sesia originates from Monte Rosa, which is an hour drive north of Boca and Gattinara. Not far from the source of the Sesia lies one of the biggest (former and now closed) gold mines of Europe: put two and two together, people thought that visitors were looking for gold (and found this rather amusing).
In reality, those «visitors» were scientists who regularly came to take samples of rocks as part of a research project, which aimed at explaining something they could not get their head around: in the Sesia river, one can observe types of rocks which, in nature, would never be next to each other. Not only such rocks were unbelievably close, in some cases they were even fused into each other.
In 2009, James Quick (professor of Earth Sciences at the Southern Methodist University of Dallas, Texas) and Silvano Sinigoi (full professor of Petrography and Petrology at Università degli Studi di Trieste) deciphered this geological puzzle. The Sesia River's path unfolds like a journey through the Earth's crust, revealing Boca and Gattinara as the remnants of the ancient caldera, and showcasing the aftereffects of the colossal eruption.
As one walks north from Gattinara or Boca towards Monte Rosa, it is like «descending» to the centre of the Earth into the heart of the volcano, gazing at rocks that normally lay buried up to 30 kilometers. As you walk around the Colline Novaresi, you can appreciate the result of the deposition of alluvial debris, collecting volcanic material from the depths of the Earth’s crust.
As winemakers, we are so grateful to prof. James Quick and prof. Silvano Sinigoi for publishing this validated finding. We wonder if these scientists, at the time, were aware of how precious their work proved to be also for the winemaking community of the region.
How does the super volcano relate to the DOC system in Alto Piemonte?
The geological masterpiece of the Valsesia Super Volcano has profound implications for viticulture, differentiating Alto Piemonte from all other wine regions. The rocks of this super volcano intricately determine soil composition, its physical and chemical properties, and influence grape ripening, infusing our wines with distinct sensory notes.
At the end of the 1960’s, Alto Piemonte was called (along with many other Italian regions) to establish geographical indications for DOC wines. One fact that always strikes people is that Alto Piemonte established 7 «single village» appellations (let’s call them like that to simplify things) in a very small area: Gattinara, Boca, Ghemme, Fara, Sizzano, Lessona and the Bramaterra enclave.
Just a couple of hours drive south of Alto Piemonte, and working with the same grape variety, the Barolo appellation (which now includes 11 villages) had gone the opposite way, even though the distances were quite similar. From Roddi to the north, down to Monforte in the south, it’s about 20-25 minutes drive, which is very similar to the distance between the northern Alto Piemonte village of Boca and the southerly Fara. The same can be said east to west: if you go from Cherasco to Grinzane Cavour in the Barolo zone, the drive is not much different compared to going from Lessona to Ghemme in Alto Piemonte.
Wouldn’t it have been more «effective» (under many points of view, marketing being the most obvious) to establish one «strong» premium appellation, inclusive of all the premium villages?
It wasn’t an easy decision, but the wines were there to guide producers: the differences are astonishing, even though the villages were relatively close by. At the time, producers had no idea of the super volcano and all the implications, but their effort of remaining «true to the wines» and expressing the differences through tiny subregions has left us with an invaluable heritage. We can rightfully say that our wines are so terroir expressive that their aromatic and structural features «anticipated» what science proved to be true and accurate 40 years later (once again, in vino veritas…).
At Vallana, we are proud to be part of this reality and we consider it a privilege to express a terroir which such a strong site specific vocation, a true call to embody a sense of place, through Nebbiolo.
What are the winemaking consequences?
While geology has provided us with great insights about the origins of our soils, it is through pedology that we have conducted our winemaking research aimed at expressing territorial features. Pedology gets into site specific details of a soil, conceived as the bridge between the Earth's crust and life: a dynamic, complex system of minerals, gases, liquids, and organic matter that fosters biodiversity.
We work with two principal soil types of Alto Piemonte:
Inceptisols of Boca and Gattinara: these are young, close-to-the-rock soils, characterized by high acidity (low pH), excellent drainage, rich mineral content and relatively low organic matter. In Gattinara and Boca, the Super Volcano's vineyards are perched close to the bedrock, with grapevine roots directly intertwined with the fossilized volcanic rocks. The vines have to «dig their way» through them to find water and nutrients. Here, Nebbiolo yields wines which are more restrained in youth, but have the potential to achieve outstanding finesse and express unique aromas through oak maturation and bottle aging (we can easily line up vintages belonging to 8 different decades).
Alfisols of Colline Novaresi: these soils formed from volcanic materials carried by the Sesia River, blending the typical minerals of the volcano's surface with rocks from deeper layers. They are slightly less acidic (depending on the zone), and generally more fertile. With diverse exposures, winemakers can cultivate a variety of grapes, resulting in a wide range of wines from refreshing rosés to medium-bodied reds and complex whites. These soils provide a unique key to deciphering the terroir's essence, explaining the core differences not only between Alto Piemonte and other Piedmont regions but also within the various denominations of Alto Piemonte itself. The best spots for producing age worthy Colline Novaresi Spanna have low pH and are rich in sand, shell and sea sediment. Colline Novaresi Spanna is more approachable in youth, thanks to the more fertile soils, and still rivals with the top world wine regions for aging potential when grown on the best sites.
What is the role of climate?
When it comes to the expression of Nebbiolo, the role of climate is essential. Climate orchestrates the nuances and intricacies in our wines. Alto Piemonte sits in the temperate zone of Northern Italy and it has a sub-alpine moderate climate, due to the presence of the Alps, the river Sesia, and the nearby lakes, Orta and Maggiore.
The diverse microclimates within Alto Piemonte, sculpted by altitude, slope aspect, and exposition, translate into distinct flavors and characteristics. The moderate summers, cold winters, and high diurnal temperature ranges create the perfect conditions.
Three exceptional microclimates epitomize the diversity within Alto Piemonte:
Gattinara: with altitude, steep slopes, and a south-facing exposure, Gattinara offers a uniform microclimate. This is where the day-night temperature range is dramatic, especially during the grape ripening period, thanks to the unshielded cool masses of air that come down from Monte Rosa during the nigh. Nebbiolo here is elegant, varietal expressive and very structured.
Boca: characterized by complex geomorphology, in Boca you will find an amazing collection of microclimates within a very small area. Moreover, it is the northernmost single village DOC in Alto Piemonte, typically the latest and slowest to ripen. Winemakers here cultivate Nebbiolo alongside Vespolina and Uva Rara, yielding complex, finely aromatic wines with bright acidity and a more supple mouthfeel.
Colline Novaresi: the rolling hills of Colline Novaresi are known for their diverse exposures and slopes. This diversity leads to wines ranging from refreshing rosés to medium-bodied reds and complex mineral whites. In the finest vineyards, you can produce Colline Novaresi Spanna with potential for complexity, concentration of aromas and tipicity.
Why is this so important for Antonio Vallana? Our message in a bottle: unum, verum, bonum
If you read up to this point, first of all let us thank you as these contents are the result of many years of research and hard work in the vineyard, at the winery and in the market. We hope we have clarified the basics of the Alto Piemonte region when it comes to geology, climate and soil. At Antonio Vallana e Figlio we are deeply committed to continue this research, so any contribution (visiting us, giving feedback or enjoying our wines) is welcome: the journey is never ending.
We hope that next time you savor a glass of Vallana, or any other wine from Alto Piemonte, you will be carried through this fascinating symphony of geological wonders, intricate soils, and harmonious climate. Our very own message in a bottle: unum, verum, bonum.