As you may know I am taking an online wine course. This week we are learning about wines from the Americas. My assignment today was to write a blog post about the factors that affect wines from Napa and Sonoma Counties. I relished the thought of revisiting a trip I took with my son and wrote the piece based on our experiences. Here goes- Salut….

I once travelled Northern California with my son.  We started our wine-country journey in Los Carneros, an AVA that straddles Napa and Sonoma counties.  I remember thinking how dry the countryside looked, the hills a shade of tan from dried grass and scrubs.  Fog and cool afternoon breezes from San Pablo Bay to the south make for a climate ideal for Chardonnay and Pinot Noir.  I tasted Domaine Carneros Sparkling wine made form Chardonnay- delicious and crisp.  Our trip took us Northwest from there into Sonoma, where I tried some amazing Pinot Noirs made in the Russian River Valley, an AVA that runs east-west out to the Pacific Ocean.  The ‘Marine Layer’, a consistent fog that creeps in from the cold waters makes for ideal cool climate grape growing and yields delicious Pinot Noir and bracing Chardonnay.  Further north was a much drier microclimate in the Dry Creek Valley AVA.  Old-vine Zinfandel ripens on the hill above the cooler fog-prone areas.  One of my favorite wineries was at the north end of Sonoma County, just west of Napa Valley- Alexander Valley AVA.  We did a winery tour of the namesake Alexandria Valley Vineyards and thoroughly enjoyed the moderately priced Cabernet Sauvignon on offer.  The warm climate coupled with less fog allow Cabernet to fully ripen into a medium tannin, fruity wine that is approachable in youth yet has cellaring capacity.  We cut through the Petrified Forest into Napa Valley and made our way south, stopping at several wineries along the way.  You could tell the difference the further down Highway 128 we travelled.  The northern-most parts of Napa include the driest and warmest AVA’s- Calistoga, Howell Mountain and St. Helena.  The abundance of sunshine is not lost, nor is the power and depth of the wines that are grown here.  We transitioned to a slightly more moderate climate as we drove closer to the town of Napa, into the AVA’s of Rutherford, Oakville, Stags Leap and Yountville.  Iconic wineries like Opus One are located on the valley floor in Oakville where the warmth allows even ripening of Cabernet Sauvignon and Merlot, key components of the Bordeaux blend they make.  Being too far north of the bay and too far inland from the ocean keeps these areas pretty warm, but cooling air flows through gaps in the Mayacamas Mountains keeping the temps from being excessive.  Further south is the town of Napa which is basically the eastern border of Carneros where we started our adventure.

We took a Cessna for a sightseeing flight the next day, departing from Sonoma County airport and flying out to the ocean then turning north to view the Russian River Valley.   We then looped back over Sonoma County AVA and finally the Alexander Valley.  The topography was marked with more green, lush vegetation than further south in Carneros.  Viewed from above you can clearly see the effects of various micro-climates.  It also showed the greenery of the vineyards which must be irrigated due to the severe lack of rainfall in the region.

In a nutshell there are several factors that affect the wines of Napa and Sonoma.  Cold Pacific Ocean currents help to moderate the potentially very hot climate.  Abundant sunshine provides consistent ripening for grapes that can be harvested with high levels of sugar, potential alcohol and silky tannins.  The fogs from the north bay and ocean help to cool the central valleys as do gaps in the mountains allow cool air in.  

The Russian River with the Marine Layer covering the Pacific Ocean