Starting in the north, Catamarca, Salta, and Jujuy total about 6,000 hectares of land under vine. Catamarca has the most, with 3,000 hectares. Jujuy makes almost nothing besides cheap table wine. Salta is the most prestigous of the three. Salta is the highest altitude vineyard in the world, at 2,000 meters above sea level. In the summer, the daytime temperatures are 70 degrees farenheit, and at night they dip down to 54. Salta is responsible for only 2% of the total output of wine in Argentina. Controlled irrigation is a necessity here. The most successful grape here is Torrontés Riojano, which can produce a very aromatic, almost muscat-like wine, full of body and often very well balanced. Cabernet Sauvignon is the second most popular grape variety, and it is often best expressed without oak aging. Chardonnay, Chenin Blanc, and Malbec are also found in Salta.
South of Catamarca, is La Rioja. Vines have been planted here since 1591, making it the oldest wine-producing region in Argentina. La Rioja is thought to be responsible for the Riojano strain of the Torrentés grape, which has found the most success of any of the various strains of Torrontés. Apart from its history and this important grape, however, La Rioja's significance in Argentinian wine production has faded. Right now there are only 7,000 hectares under vine, as problems maintaining irrigation have hampered its growth.
Just south of La Rioja, is San Juan, Argentina's second largest wine-producing area, with 50,000 hectares under vine. The climate in San Juan is very hot, with highs in the 100's and very little rainfall. Most of the grapes in this area are used to make brandies, vermouths, and sherry style fortified wines. In the last several years however, a few winemakers have made attempts to lower yields in pursuit of higher quality wine, with grape varieties like Chardonnay, Syrah, and Viognier.
The next most southern wine region is also the largest and most imporant one-- Mendoza. With 150,000 hectares under vine, Mendoza accounts for 75% of Argentina's wine production, and 95% of its exports. This is actually a substantial reduction in output since the 1980's, which reflects the general trend towards quality among wine makers. Soil in Mendoza is generally loose, sandy and alluvial, and it has a continental climate. Temperatures can get as hot as 97 in the summer, but wine makers often use techniques like planting large trees to offer shade for the vines. Rain is moderate, but there is always plenty of available water if irrigation is needed. The most important grape variety in Mendoza is Malbec, which can produce some very high-quality, age-worthy wines that are quite complex. Mendoza also produces Chardonnay, Pinot Noir, Tempranillo, and Sangiovese. Not everything, however, produced in Mendoza is of high quality. About half of the total production is used for grape concentrate and cheap table wine only meant for local consumption.
Río Negro and Neuquén, south of Mendoza, are two regions that have only about 5,500 hectares under vine, but are areas to watch in the near future. They both feature much cooler climates that the areas to the north, and are known for producing apples. The most common grapes found here are Torrontés, Semillon, and Sauvignon Blanc.