Soil & Climate

How does a sparkling wine from desert country get enough acidity? In Mendoza, the answer is altitude. Down on the plain it's hot and dry, and grapes there would quickly turn sweet and tired. The higher the vines are planted, the cooler it gets, and the meteorologists' rule of thumb says roughly half a degree less for every hundred meters of elevation.

The Valle de Uco, the Uco Valley, lies south of the city and ranges, depending on the source, from around 900 to over 1,700 meters. There lies Tupungato with the Gualtallary zone, where vines grow between roughly 1,100 and 1,600 meters. By day the sun burns through the thin air, and at night it cools sharply. This big swing between day and night preserves the fruit acidity in the berries.

The soil tells a different story than in Champagne. Instead of chalk from the sea, there are alluvial soils carried down by rivers from the Andes, full of stones, sand and clay. In Gualtallary they contain a fair amount of limestone in places, and winemakers credit that limestone with the taut, finely etched acidity of their wines. That's the producers' interpretation, not a rule of law.

Chandon's vineyards in Agrelo, at nearly 1,000 meters, benefit from this too: the house cites pronounced temperature swings and deep groundwater from the Andes as advantages. Almost everywhere, irrigation relies on meltwater, since rain is scarce.

Altitude comes at a price. Late spring frosts and summer hail can wipe out an entire harvest, so many estates string nets over the rows. There are no chalk tunnels here like in Reims; the sparkling wines age in the cellars of the bodegas at the foot of the mountains.