Obsidian Ridge Vineyard — Planted high on the ridge separating Alexander Valley and Clear Lake, Obsidian Ridge Vineyard is a 105-acre vineyard set on a northwest facing parcel of 5 to 20% slopes, ranging from 2,300 to 2,660 feet in elevation. It is situated on the backside of the Mayacamas Range some three miles from the intersection of Sonoma, Lake, and Mendocino counties.

As part of the youngest volcanic flow in the North Coast region, the site is composed of intensely red soils shot with obsidian rock and gravel. The site benefits from cool evenings due to good air drainage, high elevation, and breezes off the Mayacamas Range.

What is it about HIGH ALTITUDE? Why do we get so excited about growing fruit at 2,640 feet, in the middle of pine trees and occasional winter snowfall? The reason is two-fold, and it revolves around one basic principle: the more vines struggle, the better the wine they produce. At high altitude, the conditions are harsher and the sunlight is much more intense. The grape skin works to protect the pulp and it does this by thickening — think about the skin as sunscreen for the pulp. Upon crush, the grape skin is what creates all the flavor and color (remember, even “red” wine grape-pulp is colorless). The thicker the skin, the better the extraction, the more extraction — the better the wine. Simple!

So why doesn’t everybody plant Cabernet and Syrah at altitude? Well, for two reasons — first, it’s risky (it’s harder for the fruit to get ripe, but ironically global warming is helping), and second, there’s very little North Coast of California land available for this purpose. It’s basic supply and demand for land, which is why you would pay $60 to $80 for an equivalent Napa Valley high-altitude Cabernet. Can we keep this vineyard our little secret?

And why all the excitement about obsidian rock. To be frank, we don’t know exactly what effect the black, glassy rock that litters our vineyard has on wine quality. For one thing, refraction and heat retention from the black Obsidian translates into additional sunlight intensity. For another, rocky soils means additional struggling for the vines as well as good drainage. The better drainage and the less vigor — you guessed it — the better the wine. The Romans had a saying for this: Vitis amat colles, or ‘Vines love the hills.’

Update September 2009:  Obsidian Ridge is proud to have founded and chaired The Elevation of Wine: The First International High Altitude Viticultural and Winemaking Symposium in 2007 (click here to download a press release about the original symposium). In January 2010, at the Unified Symposium of wine, there will be a follow-up study and discussion on the effects of elevation on wine. More information at theelevationofwine.org.