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Petaluma Gap: Cooling Wind is the Recipe for Fine Wine

The Petaluma Gap is both an opening in the coastal hills of southwestern Sonoma County allowing marine air to pass into the Bay Area and Russian River Valley (a term coined by local winegrowers over 15 years ago), and a geographic winegrowing region defined by the cooling “wind tunnel” effect resulting from this break in the coastal mountain range. This region, part of the large, 50,000-acre Sonoma Coast appellation (AVA), extends from the Pacific Ocean to San Pablo Bay, comprising an area of low lying land 21 to 30 miles wide.

Because of the low terrain in the Petaluma Gap, there is little resistance to the marine air that rushes in daily, bringing with it the cooling coastal fog. A typical day in the Petaluma Gap begins with a blanket of cool, damp, morning fog. By 11:00 am, the sun chases away the fog and the temperature rises as much as 50º F. By mid afternoon, the cool on shore breezes begin, gathering speed as the afternoon progresses, and bringing in the almost nightly fog, and a temperature drops returns.

The predominant wind pattern in the Petaluma Gap is for funneled marine air to move eastward from the coast toward Sonoma Mountain, then to split into northward and southward paths. The northward path enters Cotati and diminishes as it travels toward Santa Rosa. The southward path travels unabated through the Lakeville area before dissipating at San Pablo Bay.

The nature and speed of the wind makes the Petaluma Gap region distinctive from other California winegrowing regions. The PGWA has emphasized this with their tagline, “From Wind to Wine.” Hourly average wind speeds throughout the Petaluma Gap exceed 8 miles per hour more than 90% of the time every afternoon during the wine grape growing season. Winds exceeding 20 miles per hour are not uncommon. This cooling “wind tunnel” effect prolongs hang times and slows photosynthesis, allowing wine grapes to reach physiological ripeness at lower sugar levels while maintaining ideal levels of acidity.

Michael Browne, winemaker at Kosta Browne Winery in Sebastopol has sourced grapes from three vineyards in the Petaluma Gap: Gap’s Crown, Terra de Promissio and Griffin’s Lair. He told me, “I feel the Petaluma Gap is a very special place. The wind and influence from Bodega Bay is epic. Some sites close to the coast are pretty warm due to their location although some are very cold. The Petaluma Gap receives direct fog influence, therefore cooler than most regions resulting in more even ripening of fruit. We tend to get fruit from this region that is elegant yet intense in character due to the fog and wind. I feel the Petaluma Gap is a very high quality region for Pinot Noir and one in which we have invested quite a lot due to is quality.”

The photo below was taken at Pfendler Vineyards on the eastern face of Sonoma Mountain. Beyond the vineyard, one can see the low-lying Petaluma Gap region in the distance and the break in the coastal mountains in the far distance.

The Petaluma Gap has a 150-year tradition of growing grapes and producing wine. General Vallejo was the first to plant grapevines in the Petaluma Gap region near Petaluma Adobe. The area’s first winery was founded in 1884 by G.V. Fischer, and about the that time, two other large wineries prospered in the Lakeville area.

The resurgence of interest in planting premium wine grapes began in the early 1990s. Today, according to the Sonoma County Winegrowers and Sonoma County Vintners, there are over 4,000 acres of vines (about 12% of the Sonoma County total), producing 12,000 tons of grapes and 720,000 cases of wine annually with a retail value of $900 million. Of the 80+ vineyards, most are 4 to 20 acres in size. The leading varieties are Pinot Noir (75%), Chardonnay (13%), and Syrah (12%). 9 licensed wineries are located in the Petaluma Gap region.

In 2005, the Petaluma Gap Winegrowers Alliance (PGWA) was established. The PGWA has promoted Petaluma Gap wines to the media and consumers, with the goal of establishing a reputation for wines crafted from Petaluma Gap grapes and distinguish themselves from the West Sonoma Coast growers who are also in the Sonoma Coast AVA. Members of the group have found recently that the Alcohol and Tobacco Tax and Trade Bureau (TTB) is disallowing the term “Petaluma Gap” anywhere on wine labels, because they consider the Petaluma Gap to be “viticulturally significant.” As a result, the PGWA has begun the process of developing a petition for a Petaluma Gap AVA that would allow vintners to clearly label their wines as “Petaluma Gap, Sonoma County.”

The PGWA is currently in the preparation stage of creating a Petaluma Gap AVA petition and plan to submit it to the TTB the first quarter of 2015. The process is complicated and expensive, and may take two years or longer for approval. Considerable climate and wind data must be collected to establish distinguishing features that differentiate the proposed AVA from surrounding regions in all directions, as well as establishing the exact boundaries of the proposed Petaluma Gap AVA. There are at least 30 different soil types in the Petaluma Gap so this will not be a distinguishing feature.

The boundaries as shown on the map above are subject to change. A few vineyards in the southwestern corner of the proposed boundary are in Marin County. One issue is the overlap of the current Petaluma Gap boundary in the northeastern corner with the Russian River Valley. There are eleven vineyards in this overlapped area. The original Petaluma Gap map was drawn in 2005, but since then, the boundaries of the Russian River Valley AVA have been extended twice despite opposition that claimed the area was more aptly included in the Petaluma Gap region. It is unlikely that the Petaluma Gap AVA submission will include the overlap, since guidance from the TTB indicates that such a petition would not be approved.

On November 17, 2014, I attended a presentation in San Francisco by the PGWA regarding the proposed Petaluma Gap AVA with an accompanying tasting of Petaluma Gap wines. This sampling of 5 Chardonnays, 10 Pinot Noirs and 5 Syrahs did not lend itself to establishing a discerning character of the wines from the Petaluma Gap. The variable vinification methods and winemaker’s imprint overshadowed any consistent Petaluma Gap signature. That said, the quality of many of the wines were superb, and I have included some brief comments about the wines here.

Chardonnay (all wines were barrel fermented and underwent 100% malolactic fermentation)

2013 Fogline Fogline Home Vineyard Zephyr’s Block Sonoma Coast Chardonnay 13.3% alc., pH 3.25, TA 0.66, 145 cases, $38. The most acid-driven wine in the tasting. Aromas of lemon curd, pear, vanilla and nutty oak. Bright citrus, apple and pear flavors with a subtle contribution from smoky oak. The mouthfeel was slightly creamy and the refreshing finish ended on a soprano note.

2013 Pfendler Pfendler Vineyards Sonoma Coast Chardonnay 14.2% alc., 224 cases, $38. Moderately deep straw color. The nose is a bit austere, with demure aromas of lemon and marzipan. The citrus-driven core had good length, bracing acidity, complimentary toasty oak and a slightly viscous texture.

2013 Keller Estate La Cruz Vineyard Sonoma Coast Chardonnay 14.1% alc., pH 3.60, TA 0.60, 818 cases, $38. Lovely aromas of tropical fruits including pineapple, and lemon. Fresh, clean and sleek, with a good cut of acidity, this wine was more mineral-driven, finishing with a crisp squeeze of lemon.

2012 Sojourn Cellars Sangiacomo Roberts Road Vineyard Sonoma Coast Chardonnay 14.1% alc., pH 3.62, TA 0.60, 825 cases. My least favorite Chardonnay of the tasting with austere aromas of oak and little fruit, and flavors of citrus, apple and almond. Reasonably good fruit richness with a shallow finish.

2012 La Follette Sangiacomo Roberts Road Vineyard Sonoma Coast Chardonnay 13.5% alc., pH 3.49, TA 0.62, 835 cases, $38. This wine offers a very pleasing merger of citrus fruit and oak. There is a nice touch of spice, a slightly creamy mouthfeel, perfect integration of acidity, and good intensity and length on the pleasing finish. This was the standout Chardonnay in this tasting.

Pinot Noir

2012 Baliwick “Borderline” Marin County Pinot Noir 14.1% alc., pH 3.72, TA 0.61, 300 cases, $28. From Kendric and Chileno Valley vineyards. Moderately light reddish purple color in the glass. The aromas of cherries and red berries are accented with hints of smoky oak and dried herbs. Relatively light in weight, yet flavorful, with a well-spiced core of fresh cherry and strawberry essence. Soft and silky in the mouth, with a good cut of acidity and respectable finishing presence.

2012 Couloir Chileno Valley Vineyard Marin County Pinot Noir 13.8% alc., TA 0.68, 193 cases, $44. Moderate reddish purple color in the glass. A stunning wine with hi-tone aromas of cherry, spice and smoky oak and intense flavors of fresh black cherry, black raspberry and spice. The wine is modest in weight with bright acidity, well integrated oak, and a juicy finish.

2012 Fogline Vineyards Sun Chase Vineyard Sonoma Coast Pinot Noir 13.9% alc., pH 3.44, TA 0.65, 195 cases, $42. Moderate reddish purple color in the glass. Aromas of darker red cherries and berries, marzipan and vanilla lead to mid weight flavors of black cherry and raspberry clothed in ruddy tannin, finishing with good intensity and aplomb.

2012 Wind Gap Sun Chase Vineyard Sonoma Coast Pinot Noir 14.2% alc., pH 3.58, 161 cases, $60. Moderately dark reddish purple color in the glass. A somewhat disjointed wine with too much oak overlay, tasting more of tobacco than dark berry fruits that form the core of the wine.

2013 Keller Estate “El Coro” Sonoma Coast Pinot Noir 14.2% alc., pH 3.62, TA 0.58, 396 cases, $52. Moderate reddish purple color in the glass. Engaging aromas of black cherry, sous-bois and oak. Still young and somewhat closed, yet showing enough vanilla-enhanced black cherry flavor to promise future pleasure. The velvety mouthfeel is very seductive.

2013 Pfendler Pfendler Vineyards Sonoma Coast Pinot Noir 14.5% alc., 350 cases, $45. Moderate reddish purple color in the glass. Nicely perfumed with fresh cherry pie glaze and baking spice. Charming on the palate, with inviting red cherry flavor. The tannins are supple and the texture is silky. Very forward and highly enjoyable now.

2012 Kosta Browne Gap’s Crown Vineyard Sonoma Coast Pinot Noir 14.5% alc., pH 3.48, TA 0.59, 2,186 cases, $84. Moderately dark reddish purple color in the glass. A ripe, fruit-driven wine with aromas of black raspberry and black grape juice, with a moderately rich charge of black cherry and black raspberry fruits. Very friendly, with soft tannins and a generous finish.

2013 Guarachi Family Sun Chase Vineyard Sonoma Coast Pinot Noir 14.5% alc., pH 3.60, TA 0.60, 915 cases, $65.Moderate reddish purple color in the glass. Very shy fruit on the nose, with aromas of dark chocolate and toasty oak predominant. Rather linear, tight and dull, with a generous core of dark berry fruit and balancing tannins. This wine needs at least a year in bottle to blossom.

2012 La Follette Sangiacomo Roberts Road Vineyard Sonoma Coast Pinot Noir 14.1% alc., pH 3.62, TA 0.60, 300 cases, $40. Moderate light reddish purple color in the glass. Nothing but oak on the nose. The pleasant dark berry fruit is clothed in oak. The tannins are moderate and there is superb backing acidity. Not to my taste.

2013 Sojourn Cellars Gap’s Crown Vineyard Sonoma Coast Pinot Noir 14.6% alc., pH 3.59, TA 0.58, 825 cases, $54. Moderate dark reddish purple color in the glass. A very seductive wine with bright aromas of dark cherries, spice and graham. The mid to full-bodied flavor of black cherry is delicious and expansive. A beautifully crafted, harmonious wine that is sexy for want of a better word.


Syrah struggles to ripen in this region, so the wines have considerable variability. The potential is evident though.

2012 Waxwing Flocchini Vineyard Sonoma Coast Syrah <13.4% alc., pH 4.0, TA 0.46, 60 cases, $32. Dark reddish purple color in the glass. Aromas and flavors of purple and black berries in a mid weight style with balanced tannins and some length on the finish. There is a curious bubblegum note on the palate.

2004 Clary Grower’s Reserve Shazzam Sonoma Coast Syrah 13.4% alc.. Dark reddish purple color in the glass. Aromas of black fruits and underbrush lead to a tasty core of juicy black fruits accented with peppery spice. This wine has aged beautifully and is still fresh and giving.

2011 Keller Estate “Rotie” Sonoma Coast Syrah 14.1% alc., pH 3.77, TA 0.61, 429 cases, $52. Moderately dark reddish purple color in the glass. An impressive offering with scents of dark cherry reduction sauce, brown spice and graham. The middleweight flavors of black cherry and black plum are enhanced with spice and subtle oak. Nicely composed with balanced tannins and a sleek, long finish.

2012 Bedrock Griffin’s Lair Vineyard Sonoma Coast Syrah 14.6% alc., 200 cases, $42. Dark violet color in the glass. A brooding, tannic wine with a full-bodied load of black fruits accented with tobacco oak. This wine is hard to embrace by itself, and would benefit from some accompanying grilled protein.

2011 Pax Griffin’s Lair Vineyard Sonoma Coast Syrah 13.9% alc., 300 cases, $62. Dark violet color in the glass. Very pleasing aromas of well-ripened purple and black berries with a compliment of sweet oak. Full-bodied and luscious, with a charge of boysenberry and blackberry flavors that maintain intensity through a big finish. A note of peppery spice adds interest. The tannins are bold and muscular, but not out of balance with the generous fruit load.

For more information on the proposed Petaluma Gap AVA and the Petaluma Gap Winegrowers Alliance, visit Petaluma Gap member wineries with tasting rooms (some require an appointment) include Azari Vineyards, Cline Cellars, Couloir Wines, Enriquez Estate, Fogline Vineyards, Karah Estate, Keller Estate, McEvoy Ranch, Ramey Wine Cellars, Saltonstall Estate, Sojourn Cellars, Sonoma Portworsk, Trombetta Family Wines, WALT Wines and Wind Gap Wines. There are many wineries that buy Petaluma Gap fruit and some of them are the most famous wineries in Sonoma County including Cobb Wines, Donum Estate, Flowers Vineyard & Winery, Freeman Winery & Vineyards, Hartford Family Winery, Kendall Jackson Wine Estates, Schug Winery, Soliste and Twomey Cellars.

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