The grape farmer’s first challenge involves matching grapes to the proper terroir, starting with the “macroclimate”—the broad region in which grapes will grow. Globally, this means finding a suitable vineyard site that falls between latitudes of 30 and 50 degrees. In the Northern Hemisphere, this range extends from southern Canada southward to the northern reaches of Mexico and from northern Europe to the north tip of Africa. In the Southern Hemisphere, favorable wine regions encompass the southern part of South America, South Africa and the southern parts of Australia and all of New Zealand. Areas north or south of these ranges tend to be too hot or too cold for optimum grape growing.
Within each macroclimate is the “mesoclimate”—the actual vineyard site. Don’t confuse this term with the “microclimate” (see: “Vineyard Management”). Unique features, such as hillsides, mountain sites and nearby waterways can create conditions substantially different from even nearby mesoclimates. For example, high altitudes in Argentina’s Andes Mountains consist of exceptionally cool climates with long, sunny days as compared to other parts of Argentina. Northern California’s San Pablo Bay creates cool breezes and morning fogs in Carneros, a cool enclave that straddles parts of Napa and Sonoma Valleys.
Once the farmer knows the mesoclimate, it’s time to select grape varieties. The ultimate goal is to produce grapes that mature gradually (producing complex and concentrated flavors) while maintaining the right proportion of acidity (ensuring crispness, balance and integrated flavor). But it’s not as easy as it appears. Too much acidity—the result of unripe grapes—can make unpleasantly tart wines. A warmer climate will help grapes mature and develop necessary sugars, but it also drops acidity levels. Excessive rain—particularly in late summer and into harvest time—also poses a challenge as grapes swell with water and produce diluted wine.
Farmers can achieve the optimal balance when the right grape is planted within the right climate. For example, Pinot Noir does best in a moderate to cool climate, such as that of Burgundy in France, Oregon in the United States and New Zealand. On the other hand, Syrah thrives in warmer climates, such as France’s Rhône, warm regions in Australia and in California’s Paso Robles, which is nearly 250 miles south of Napa and Sonoma.