Are there any significant differences between Napa cabernet sauvignon that is mountain grown (Diamond Mountain, Howell Mountain) as opposed to Napa cabernet sauvignon that is grown on the floor of Napa Valley?
Answer From Expert Roger Bohmrich MW
The answer is a complicated one as there are many examples which make it difficult to make definitive claims. In fact, Napa is far more complex in terms of soils and climate than is generally recognized, and the location of vineyards on the valley floor and the surrounding elevations makes it even more difficult. In general terms, "mountain" vineyards are by definition higher than the valley floor and tend to be cooler, although a great deal depends upon the particular location and the cooling influence of fog and air from the Pacific. Howell Mountain, however, is less affected by fog. The upper Mayacamas vineyards are above the fog line and enjoy morning sun, yet are cooler in the afternoon. Mountain vineyards are usually on slopes of thinner, less fertile soils. On the whole, some of the wines from these elevated locations are more structured, tannic and less approachable when young than valley floor equivalents - but there are contrary examples, and it is challenging to pin down styles.
