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. Although primarily associated with the Rhone region of France, the precise origins of the Viognier grape variety are unknown, and the subject of much debate. However, these fine and delicate green skinned grapes are an important varietal for many of France's most elegant white wines, and they are quickly beginning to spread around the New World, too, where wineries are discovering their unique qualities and unusual character. Viognier grapes are notoriously difficult to grow, due to the fact they are highly susceptible to mildew, but wineries persevere with them nonetheless, producing wines which are highly aromatic and have a great, fruit-forward character. Their delicate aroma suggests sweetness due to its flowery, sappy nature, but the wine itself generally very dry and crisp, and full of summery, light and refined qualities.