http://www.winespectator.com/Wine/Wine_Basics/Wine_Basics_Template/0,,1004,00.htmlVarietal Characteristics
By James Laube, with James Molesworth
In order to appreciate wine, it's essential to understand the characteristics different grapes offer and how those characteristics should be expressed in wines. Cabernet Sauvignon, Merlot and Zinfandel are all red grapes, but as wines their personalities are quite different. Even when grown in different appellations and vinified using different techniques, a varietal wine always displays certain qualities, which are inherent in the grape's personality. Muscat should always be spicy, Sauvignon Blanc a touch herbal. Zinfandel is zesty, with pepper and wild berry flavors. Cabernet Sauvignon is marked by plum, currant and black cherry flavors and firm tannins. Understanding what a grape should be as a wine is fundamental, and knowing what a grape can achieve at its greatest is the essence of fine-wine appreciation.
In Europe, the finest wines are known primarily by geographic appellation (although this is changing; witness the occasional French and Italian varietals). Elsewhere, however—as in America, Australia, South Africa and New Zealand—most wines are labeled by their varietal names; even, sometimes, by grape combinations (Cabernet-Shiraz, for example). To a large extent, this is because in the United States, the process of sorting out which grapes grow best in which appellations is ongoing and Americans were first introduced to fine wine by varietal name. In Europe, with a longer history for matching grape types to soil and climate, the research is more conclusive: Chardonnay and Pinot Noir, for instance, are the major grapes of Burgundy. Cabernet Sauvignon, Merlot, Cabernet Franc, Malbec and Petite Verdot are the red grapes of Bordeaux. Syrah dominates northern Rhône reds. Barolo and Barbaresco are both made of Nebbiolo, but the different appellations produce different styles of wine. In Tuscany, Sangiovese provides the backbone of Chianti. A different clone of Sangiovese is used for Brunello di Montalcino.