Alto Adige is nestled in the Alps; that makes it a cool-climate region, right? Wrong! Bolzano is often warmer in the summer than Sicily! Let’s see how terroir affects the wines.
The Adige and Isarco rivers etched this Y-shaped valley over a millenia to make a viticultural haven.
With a mosaic of microclimates, valleys, and soils, Alto Adige grows everything from deeply-colored red wines like Lagrein to delicately perfumed Gewürztraminer.
What is terroir and how does it affect wine?
Terroir ("tear-wah") is a French word that's difficult to understand, but it loosely translates to a land's potential to produce agriculture. Interestingly enough, where and how the grapes grow affects how wine tastes.
To better understand terroir, let's break it into three categories:
- A wine region's climate
- The soil and terrain conditions
- Common winemaking practices
Together, these three characteristics help explain why certain wines from specific places have this "je ne sais quoi" – an undefinable yet unmistakable taste.
The Alps are a major part of the terroir in Alto Adige because they do three things:
- Act as a rain shadow.
- Create a large diurnal range.
- Provide various elevations for planting different types of grape varieties.
The rain shadow creates Alto Adige's warm climate
The Alps create a rain shadow for Alto Adige ensuring more than 300 sunny days per year! It equates to 1,950 hours of sunshine. The result is Alto Adige has an average growing season temperature of 64 ºF (18 ºC), making it a warm climate for wine.
To put that into perspective, that's about as much warmth as Sonoma Valley in California!
The sunshine helps give ripe fruit flavors to all the wines and can lead to fairly high levels of alcohol ranging from 12.5%–15%, depending on the wine.
While the Alps protect Alto Adige from northern storms, the region still receives plenty of rainfall (32 inches/815 mm a year) here for vines to flourish. However, due to high temperatures in the summer months some producers use drip irrigation to help their vines.
Hot days and cold nights help with aromatics
Warm days and cool nights in Alto Adige create a high diurnal range which is the key to high acidity and delicate, floral aromas in wines.
For example, the average daytime temperature heats up to 86° F ( 30° C) in July. But at night, the temperature drops to 61° F (16° C) on average. The shift is even more significant in vineyards at higher altitudes.
Elevation allows for a huge diversity of wine varieties
The incredible range of elevation in Alto Adige from 655–3,300 ft (200-1000m) above sea level makes it possible to grow a wide variety of wines.
- White wine varieties like Riesling, Kerner, and Sylvaner grow well in higher elevations where it's cooler.
- Red grape varieties such as Lagrein and Schiava (Vernatsch) prefer lower elevations where it’s warmer.
Certain grape varieties prefer certain soils in specific climates to produce excellent quality. But it's not that simple here. Alto Adige sits on the intersection of the African and European tectonic plates, which create more than 150 different soil types!
Fortunately, three soil types create incredible wines to know about:
Porphyry is great for aromatics
Porphyry (“Poor-fur-ree”), a volcanic-origin soil, features lots of iron and quartz and looks red. For Gewürztraminer, it super-powers this wine's lovely floral aromatics. It's also known to add stone-like and mineral-like notes. You'll find Porphyry mainly around Bolzano.
Dolomitic Limestone is great for liveliness and age-worthiness
Remnant soils of the ancient Tethys Ocean (that covered this part of the world during the Mesozoic Era) created Alto Adige's dolomitic limestone.
This soil type is known to retain acid in grapes which makes wines taste more fresh and lively. Dolomitic limestone is found throughout Alto Adige, but mainly south of Bolzano.
Quartz, Slate, and Mica make for minerality
Rocky soils give wines a strong mineral edge but also help create fruity aromas. How? Well, quartz, slate, and mica soils reduce acid levels in wines, which increases the "fruit factor" in wine.
It works great with Riesling in cool climates. In Alto Adige, we find these soils in the cooler Valle Isarco and Val Venosta areas.
Lake Garda makes red wine possible in Alto Adige
Lake Garda, the largest lake in Italy and situated 60 miles (100 km) south of Bolzano, might not seem like an essential feature to Alto Adige. Still, it has a significant impact on the local climate.
Each day the air in Alto Adige is heated by the sun, causing the warm air to rise. Displacement pulls cooler air over Lake Garda northwards. This happens daily around noon and runs like clockwork. Called the Ora, meaning "hour" in Italian - mainly because it's so punctual!
The wind reaches upwards of 25 miles per hour, creating a vacuum over Lake Garda which then, in turn, funnels warm air from the Po Valley and Mediterranean Adriatic Sea towards Alto Adige, creating a wonderful climate in the southern valley to ripen red grapes, like Schiava (Vernatsch) and Lagrein.