“We make mountain wines here,” says Sebastián Zuccardi, stating the obvious. He’s standing in front of the solid-stone winery he built two years ago in Uco Valley’s Altamira district at nearly 4,000 feet above sea level where his estate vineyards practically hug the snow-capped Andes Mountains.

Since joining his family’s Maipu-based wine business, founded by his grandfather in the 1960s, Zuccardi has been convinced that Uco Valley is the future for Argentina, and he has devoted most of his energy and resources to getting as close to the mountains as possible.

“The combination of calcium carbonate-rich, alluvial soils at this elevation is unique to Uco Valley,” he explains. “We can make fresh, mineral-driven, high-energy wines here—totally different from the fruity, formulaic Malbecs that people associate with Mendoza. Uco is barely two decades old, so we are just now beginning to understand our terroir.”

Zuccardi is among a growing group of passionate producers working to classify Uco’s high-elevation terroirs and petition for Geographical Indication (GI) status for the emerging districts that, although young, are responsible for Argentina’s paradigm-shifting wines.

Too High, Too Cold, Too Harsh

When Nicolás Catena planted his Adrianna Vineyard in Uco’s Gualtallary district in 1993, most believed he would fail. Lower Uco had some vineyards, but no one had dared cultivate grapes at 5,000 feet above sea level; the risk of frost was extreme, and growers assumed grapes couldn’t ripen in the harsh, high-desert landscape.

But Catena was determined to find the coldest place in Mendoza to plant vines, and the introduction of drip irrigation to the region meant that viticulture at higher sites was finally possible. He set up weather stations throughout the region and discovered that while temperatures were similar to Champagne, the brightness and extra hours of the sunlight could result in the holy grail of winemaking: “Grapes on the edge of ripeness with fully mature tannins, natural acidity, and only 13 percent alcohol,” explains his daughter Laura Catena, who now manages the family’s Bodega Catena Zapata.

Around the same time, Dutch entrepreneur Mijndert Pon saw similar potential in Uco’s higher reaches. But instead of a single vineyard, he bet much bigger, planting hundreds of acres of mostly Malbec vines between 1996 and 1999, and constructing a massive, gravity-fed winery christened Bodegas Salentein. The first to put “Uco Valley” on its labels, Salentein is locally regarded as the region’s “locomotive.”

The results from these pioneering vineyards were evident within several harvests. Grapes grown here possessed higher minerality, more acidity, and firmer tannins compared to lower sites. “I had never seen acid levels like this in Argentina before,” describes Salentein’s winemaker of 20 years, José “Pepe” Galante (formerly the winemaker at Catena). “They are the same as Chablis.”

Word spread quickly. The last two decades have seen explosive growth in Uco with dozens of new wineries and high demand for Uco fruit from producers outside the region. Vineyard prices have increased twenty times in some coveted districts. Trailblazers have continued to test limits, planting successful vineyards well over 5,000 feet and others are pushing higher still: José Lovaglio, owner and winemaker of Vaglio, and the son of Susana Balbo, has planted a Pinot Noir vineyard (not yet in production) in Uco’s La Carrera district that sits above 6,500 feet.

An Appellation Renaissance 

As many of these original vineyards come of age, the terroir conversation has shifted from simply elevation to include soils, a topic Uco winemakers are obsessive about. Some vineyards have dozens of calicatas—eerily grave-like pits dug in between vines to expose various layers of subsoil. Some reveal large round boulders, others marine fossils, pebbles, or chalky calcium carbonate deposits; various combinations of material left behind when glaciers and rivers pushed alluvial deposits down the slopes of the Andes millions of years ago.

Zuccardi dug 180 calicatas in his Piedra Infinita vineyard alone (source of the acclaimed single vineyard Piedra Infinita Malbec), which uncovered 40 different soil types. Laura Catena identified more than 200 distinct parcels in the Adrianna vineyard, which she now vinifies separately. For producers here, the tremendous diversity of soils and microclimates is what makes Uco so distinct from Mendoza’s two other growing areas—Maipu and Lujan de Cuyo—and what they believe calls for a more specific classification system.

“Our growers have been pushing hard for this GI system in Uco to focus on regional specificity,” says Jonathan Chaplin, co-founder of Brazos Wine, a Brooklyn-based import company which represents many of the new small-scale Uco producers. “No one in Argentina was talking about regions ten years ago, and today that’s all we do—we bring maps everywhere.”

This new laser focus on terroir coincides with a move towards a fresher wine style in Uco—and not only from the younger generation of producers. “Today we make wines that are focused on the place, with less new oak and earlier harvest dates,” says Zuccardi, who installed 160 concrete eggs and large foudre at his new winery. “Working with concrete and large vats is a return to the winemaking culture of the 1930s.” Salentein and other established names like Matías Riccitelli and Paul Hobbs report picking their fruit as much as a month earlier than in the past and using more whole-cluster fermentation for added freshness. With less alcohol and extraction, a clearer picture of Uco’s regional diversity is coming into focus.

Gualtallary: A Sunnier, Drier Burgundy 

In a corner of Uco’s Tupungato region with vineyards climbing to a mile above sea level, Gualtallary stands out for its rocky, alluvial, chalky soils. Convinced this high mountain oasis was ideal for organic farming, Languedoc vigneron Jean Bousquet planted vineyards in the shadow of the Tupungato mountain in the early 1990s. Today, Domaine Bousquet is the largest exporter of organic wine from Argentina, producing 300,000 cases of (shockingly affordable) wine. Bousquet just debuted their first unoaked, sulfite-free wine, Virgen Malbec.

“Gualtallary is freshness and elegance,” says daughter Anne Bousquet, who now runs the domaine. “We get bright red berry, mineral, and floral notes in our wines, as well as more structure.” Indeed, The Catena Institute research center found that the unique luminosity of mountain sunlight in Gualtallary increases tannins in grape skins.

Gualtallary producers find intense terroir expression coming from even very young vines. Edgardo (Edy) del Popolo and David Bonomi left jobs at commercial wineries to plant bush vines that naturally yield 40 percent less fruit than the region’s average—under one pound per plant. Their first vintage, 2012, showed an aromatic complexity and fine-grained tannins that would take years to develop in young vines grown in other regions, Popolo believes. “In Gualtallary we are able to craft wines with rare purity that really speak of their landscape.” (Gualtallary has yet to be officially approved as a GI because the name is a registered trademark owned by a single producer.)

Cabernet Franc is generating a lot of interest here today; though less than 1 percent of plantings, it’s the district’s most exciting grape, many claim. “Gualtallary is the best place for Cabernet Franc in Argentina—it needs elevation,” says Matias Michelini, who founded Zorzal with brothers Gerardo and Juan Pablo in 2007. Fermented and aged in concrete eggs, Zorzal’s Eggo Franco is peppery, savory, and earthy with electric acidity. Domaine Bousquet, Rutini, and Andeluna are also big Cabernet Franc champions here.

Paraje Altamira: Structured, Savory Malbec

In the southern Uco Valley, the Paraje Altamira district broke away from the larger La Consulta region in San Carlos in 2013—the first GI declared based on terroir research, not political boundaries, which paved the way for Uco’s GI system’s evolution. Achaval Ferrer’s Finca Altamira is arguably the district’s most famous wine; more recently Zuccardi and Altos Las Hormigas have built wineries here.

Altamira features heavier soils than Gualtallary, with loads of silt and calcium carbonate—and some very large rocks (which makes planting vineyards costly and difficult). Wines here tend to be fuller-bodied with dark fruit and herbs; Malbec—by far the district’s star grape—shows power and concentration with fresh acidity. Zuccardi’s Poligonos Altamira, one in a series of single vineyard Malbecs made in different districts, illustrates Altamira’s unique underlying salinity. “The calcareous soils here force vines deeper and add structure, which the Malbec variety can often lack,” Zuccardi explains.