Napa is the nation's "grand cru" appellation, and Napa vintners have been nothing if not successful in marketing the valley as America's wine Eden. Geographically, the Napa Valley is reasonably contiguous, being 34 miles in length and between one and four miles in width from the town of Napa in the south to that of Calistoga in the north. It is an easy region in which to ripen grapes and consistently produces ripe full wines. The cool air from the San Pablo Bay, just north of San Francisco, moves from south to north, thus giving the southern area cooler average temperatures.

An imprecise but useful generalization would be that the cooler southern end is more favorable to white varieties and Pinot Noir while the further north one gets, the more red varietals one will encounter as the temperatures increase, with emphasis on Cabernet. This simplification does not account for the vagaries of soil types, microclimates, and vintners throughout the valley, and as such there are many exceptions to the rule. Several sub appellations have been created since the inception of the Napa Valley AVA in 1983 and these go some way towards addressing the differences in climate between some parts of the valley. With the hugely significant exception of Carneros, these sub appellations are of more relevance to Cabernet and red wines than Napa’s other darling, Chardonnay.

The coolest area just to the north of Carneros includes Yountville and the Oak Knoll District where a mix of reds and whites are to be found. Indeed, much of this region is cool enough to produce sparkling wines. Nonetheless, some well-known vintners are here; not the least of which is Dominus. A Yountville style would be hard to pin down as there are relatively few wineries and the differences have more to do with wine making, but a safe generalization would be that the wines are not nearly as thick as those produced up the valley, and that they show a sense of elegance. Still at this cooler end of the valley yet just to the east of Yountville lies an extremely prominent appellation, however, the Stags Leap District.

Wine lovers have known for some time that Stags Leap is a special area, as evidenced since the early 70s by the wines of Warren Winiarski at Stag’s Leap Wine Cellars. It is cooler than areas to the north, as the ocean winds that move up from the San Pablo Bay act as an air conditioner and moderate the heat of the afternoon which builds up on the bare rocks of the eastern mountains that allow for the greater ripening potential than Yountville to the west. Those rocks also feature in the very different soil composition of the area. Over 95% of the soil is derived from volcanic rocks, which makes for a gravelly, well drained, and less fertile environment than that featured in the Rutherford Bench. These factors combine to draw out the ripening process, affording a longer growing season and the possibility of greater physiological maturity than other regions of the valley floor. This translates into a particularly flavorful and supple style of red wine, often marked by red berry overtones.

North of Yountville and Stags Leap is the “American Medoc,” the triumvirate of Oakville, Rutherford, and St. Helena, from coolest to warmest respectively. The names and wines read like a who’s who of the wine industry, and this narrow belt of this narrow valley has become world famous. In this area, all factors have come together to make an ideal growing climate for red Bordeaux varietals, with Cabernet Sauvignon at the fore. Furthest to the cooler southern end of the belt, Oakville produces Cabernets of great ripeness and richness with a certain restrained elegance. It is also quite common to see a distinctive minty quality intermixed with the red and black fruit flavors. Rutherford, just to the north, shows Cabernet of marginally greater weight, with considerable depth and remarkably consistent black fruit flavors, while St. Helena Cabernet adds just another layer of weight.

Finally, at the top of the valley and often a good 20 or even 30 degrees warmer than the extreme southern end lies Calistoga. As one might expect, Calistoga reds are big, rich, and ripe, with huge levels of extract. Nonetheless, the wines usually avoid the jammy, porty notes that can sometimes interject themselves into such warm climate wines. Indeed, one of the most difficult factors facing the Calistoga wine maker is managing the abundance of tannins that come naturally to these wines. As such, advances in the management of tannins that have been made in the last 20 years have helped Calistoga’s wines to a great degree. (Wine/Appellations)