When it comes to New World wines, and especially wines from the United States of America, Napa Valley is something of a standard bearer. Over its relatively short history, it has managed to transform itself from being a fairly insignificant region, to becoming one of the most important and highly regarding wine locations on earth. With an ideal climate for viticulture, blazing sunshine and a low level of rainfall, this valley is shielded on many sides by mountain ranges which help it maintain a consistent level of heat, light and moisture throughout the year. Today, Napa Valley is a home of innovation and quality, with dozens of grape varietals thriving in the fertile soils. However, the main varietals grown there have always been Cabernet Sauvignon, Chardonnay, Pinot Noir, Merlot and Zinfandel, and the wines they produce are constantly lauded by critics and competitions across the globe. The green skinned grapes of the Sauvignon Blanc varietal had their origins in Southern France, where they are still widely grown and used for many of the excellent young and aged white wines the region is famous for. Today, however, they are grown in almost every wine producing country in the world, and are widely revered for their fresh and grassy flavors, full of tropical notes and refreshing, zesty character. Sauvignon Blanc grapes thrive best in moderate climates, and ripen relatively early in the year. This has made them a favorite for many wineries in the New World, where they can still produce healthy and high yields in the earlier part of the summer before the temperatures become too hot. Too much heat has a massively adverse effect on Sauvignon Blanc, as the grapes become dull in their flavor, and the wine produced from them loses all its unique character and high points. As such, Sauvignon Blanc farmers have had a lot of trouble from global warming and climate change, as they are being forced to harvest their crops increasingly earlier in the year when it is cool enough to do so.