Argentina has an attitude about altitude.
Talk to winemakers anywhere and they'll tell you about their terroir, about soils that are sandy/loamy/chalky/stony, about microclimates that seduce sea fog in at night to cool the grapes, about how they were smart enough to buy the east/west/north/south side of the hill that's a few feet higher than the other guy's and gets the best sun exposure and the best air-drainage so the frost always slides down the slope and devastates their neighbor's vineyard.
But, these guys have the Andes!
The Andes offer three things that define Argentina's terroir: a weather break that moderates temperatures and humidity, abundant water from winter snow melts allowing winemakers to irrigate vineyards as much or little as needed, and altitude.
What does this do for the grapes? With every climb of 100 meters in altitude, the average temperature decreases by 1 degree Celsius. That means grapes with higher acidity and softer tannins. But the intensity of the sunlight also increases, allowing the grapes to achieve maximum ripeness while the cooler temperatures keep the sugars in check.
Intense sun does not equal heat. The combination of low temperatures and high-intensity sun yields red wines of high extraction, soft if not disappearing tannins, and impressive structure and balance. Carefully made, they do not have the excessive alcohol that mars so many modern, "international" wines. White wines can feature bracing acidity and verve without the need, in the case of Chardonnay, for much if any malolactic fermentation.
We conquered our fear of heights by opening a 2005 Viognier-Chardonnay 50-50 blend called High Altitude Agrelo from the Bodegas Escortheuela Gascon. James Molesworth of Wine Spectator gave it 86 points and said it has a mix of peach, melon and pippin apple flavors, with a crisp lime edge taking over on the finish. It retailed at $14.99 but we purchased it for 50% off at the fall dot sale. With a pot of homemade chicken, vegetable and broken spaghetti soup, it wasn't half bad!