A Sense of Place? The Sonoma Coast AVA


Despite a great range in winemaking styles, when I purchase a Chambolle-Musigny, I know, generally, what style of Pinot noir I will drink. Government bodies give certain areas of land a single name, an appellation, since the features important to grape growing in that area are similar. The common natural features – soil type, temperature, elevation, proximity to water, aspect – result in wines with similar characteristics and regional personality. Seems reasonable and a service to consumers to me. But, what about when a region is vast, like the Sonoma Coast?

The Sonoma Coast appellation is the largest licensed American Viticultural Area (AVA) in the United States containing over 500,000 acres across 750 square miles. The appellation runs south from the northern border at Mendocino along the coast of the Pacific Ocean until reaching Marin County. At the Russian River the boundary jogs inland to pick up a huge swath of Sonoma County previously heavy in dairy referred to by some as the Petaluma Gap. It goes even further east and northeast jumping highway 101 forty miles from the ocean and grabbing parts of the Russian River appellation up to the border of Chalk Hill. The boundary then extends south thirty miles to pick up parts of the Sonoma Valley and Sonoma Mountain appellations and even the western part of Carneros bordering San Pablo Bay. Yes, the bay you see from your car window when you cross the Golden Gate Bridge leaving San Francisco.

The only thing vineyards in this large area have in common are sites owned by an influential winery who desired to make an estate labeled wine and created the AVA while the licensing board – the BATF now the TTB, based in D.C. – was asleep at the wheel. The differences in terroir are vast and, not surprisingly, so is the style and quality of wines made from the Sonoma Coast appellation. Eventually, this appellation will break up into numerous sub-appellations that actually share common features that affect grape growing. A complicating factor, of course, is that winemakers in the New World are not restricted by tradition or regulation, like in the Old World, so ripeness at picking, oak use and other winemaking tools at their disposal can play a larger role in determining a wine’s style. But even in the face of this challenge, I am in favor of creating sub-appellations since the wines made from Sonoma Coast vineyards taste different based on whether they are grown on the coast on a ridge top above the inversion layer vs. within the inversion layer, in an alluvial plain near the ocean vs. 20-30 miles from the ocean, or on the first, second, third, or fortieth ridge from the ocean’s cooling influence.

Things take time, however, and people are beginning to recognize that there are at least two unique sections of the Sonoma Coast. The first demarcation that has gained some traction is defined by the ribbon running along the Pacific Ocean known as the “true” Sonoma Coast. Admittedly, the moniker is a little smug (it reminds me of the Life of Brian piece about the Judean People’s Front vs. the People’s Front of Judea) but it does make a point. These vineyards actually lie along the coast of Sonoma County! This means that the afternoon breeze that comes in every day around noon cools vineyards unobstructed by higher western coastal ridges keeping top temperatures out of the 90s and, for those in the cool inversion layer below 1,000 feet (more on that later), out of the 80s. The breezes and cool weather also often inhibit fruit set and a consequence of farming on the coast is that the yields are about half of what you can get inland. Our proximity to the San Andreas Fault – anywhere from a few miles to a few hundred feet from coastal vineyards – also play a role as the variety of soils along the coast is diverse. Further, the vineyards are found on rain drenched ridge tops where the soil vigor is low and most slopes are steep allowing for good drainage, sunlight penetration and tractor tipping.

What do the “true” Sonoma Coast wines have in common? Setting aside winemakers’ picking decisions and winemaking practices, the wines often have more tannin, dry fruit as opposed to juicy fruit characteristics, medium-to-high acidity and good to extraordinary length. Yet, even within the “true” Sonoma Coast there are significant differences in terroir that partially inform why the wines from these separate regions each have their own particular style.

As you can see on the map to the right, the “true” Sonoma Coast breaks into three regions: the northern region around the town of Annapolis off Sea Ranch; the central region with the oldest vineyards on the coast now referred to by some as Fort Ross/Seaview Road; and the southern region near the town of Occidental. Peay Vineyards was a pioneer in the far northern section. Vanessa’s article goes into great detail about the soils found in this area and how the top layers that we see in our vineyard differ from the soils in the Central Sonoma Coast due to the addition of marine deposits. This is, of course, very important for determining our terroir. Our location above a river gorge only 4 miles from the Pacific Ocean is also important. We are discovering, however, that a critical factor for both vineyards in the northern and for those in the southern Sonoma Coast, is our elevation.

Our vineyard lies at 650-825 feet in elevation. Normally, temperatures fall by 1°F for every 400 foot gain in elevation. Along the Pacific Coast, this phenomenon is inverted as a layer of cold air‹the inversion layer‹is produced by a warm, less dense air mass moving towards the coast over the cooler, denser air caused by oceanic upwelling along the coast. This layer is maintained throughout the day and the breezes off the coast act as a fan blowing cold air along unobstructed land laying from sea level to 1,000 feet in elevation. Above this height, as in the central Sonoma Coast, and further inland, the normal relationship between temperature and elevation apply and it is hotter. Vineyards in this inversion layer are much cooler and as a result we achieve the Holy Grail in terms of high quality grape growing: cool sunlight. In an article Nick wrote last year, he discussed how scientific experiments concluded that cool sunlight produces fruit with the most flavor, complexity and, they determined, quality. If you’d like to learn more about that phenomenon, please go to our archives where we post all past articles. The most obvious affect of farming within the inversion layer are the cooler, more even temperatures we experience throughout the season and during the day. As a result, we have smaller grapes and more ripening days at lower temperatures often picking our grapes weeks after vineyards in the central Sonoma Coast and at lower levels of ripeness. If you’re interested in the effect of a longer growing season, please see an article I wrote in the Fall 2007 newsletter, I Am Cooler Than You.

At Peay Vineyards we make estate wines. As a result I am focused on educating people on why our vineyard is unique and how that translates into great wine. At some juncture, I am sure I will be asked to help break the northern Sonoma Coast into a new appellation based on some of the features I have described above. I’m a little ambivalent about this process since I only make estate wines and not very much at that. Why waste my energy promoting a new region? In any event, I will suggest that the person who created this mess should fix it. And, guess what, as it so happens that person sold the winery that created the Sonoma Coast appellation and planted 2 vineyards down the road from me. In addition to making wine for his own label he sells fruit and thus cares about the confusion created by the diversity in quality and styles of wines from the vast Sonoma Coast appellation. Poetic justice, if I ever heard it.

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