Undoubtedly the most important viticultural region of the country of Argentina is Cuyo, the arid and red-soiled area within central-west Argentina which produces over eighty percent of the nation's wine each year. Cuyo represents the finest aspects of Argentinian wine making, with wineries in the region celebrating their traditions which stretch back to the sacramental wines first introduced to the country by Spanish settlers hundreds of years ago. As with much of Argentina, Cuyo is most famous for the production of Malbec wines, with Malbec grapes thriving prodigiously in the hot climate of the region, reaching full ripeness in ways they rarely could in their native France, and producing wines of exceptional flavor and quality. The Desaguadero River is the key water source in this otherwise dry and dusty region, and successful irrigation projects have helped bring water to even the driest vineyards within Cuyo. With its dark blue colored fruits and high juice content, Merlot varietal grapes have long been a favorite of wine producers around the globe, with it being found in vineyards across Europe, the Americas and elsewhere in the New World. One of the distinguishing features of Merlot grapes is the fact that they have a relatively low tannin content and an exceptionally soft and fleshy character, meaning they are capable of producing incredibly rounded and mellow wines. This mellowness is balanced with plenty of flavor, however, and has made Merlot grapes the varietal of choice for softening other, more astringent and tannin-heavy wines, often resulting in truly exceptional produce. Merlot is regarded as one of the key 'Bordeaux' varietals for precisely this reason; when combined with the drier Cabernet Sauvignon, it is capable of blending beautifully to produce some of the finest wines available in the world.