The Petaluma Gap AVA in Sonoma and Marin counties has finally been approved today after a long delay, making Petaluma Gap the newest AVA in the United States. The last previous AVA to be approved by the TTB was the Appalachian High Country of North Carolina in October 2016 under the Obama administration.
The Petaluma Gap AVA application had fulfilled all stages of approval during the Obama administration except for the final approval signature. The official signature was not granted under the Trump administration due to a failure of the new administration to appoint the necessary official to sign the document, and a moratorium on rulemaking created by Trump. Now that the official position has been filled and the moratorium on rulemaking lifted, it appears the approval process can begin for other proposed AVAs in the pipeline such as the Van Duzer Corridor AVA within Oregon's Willamette Valley.
Making the Petaluma Gap official clears the way for wineries to label with the new AVA wines made from grapes from within the area. The approval also marks the first official AVA in Marin County. Until now the produce of Marin's vineyards could be labelled only with the county or state name. As Rickey Trombetta, president of the board of directors for the Petaluma Gap Winegrowers Alliance (PGWA), points out, the new designation also opens the door for both improved education about the unique growing characteristics of the region, and for restaurants to celebrate the region's distinctive wines in regionally designated wine lists.
The new appellation also marks the first time an AVA has been defined on the basis of its unique wind conditions. In the TTB application for the region, the boundaries of the AVA were determined by where the wind off the Pacific Ocean through the Petaluma Gap maintains a regular speed of at least 8 mph. While the Russian River and parts of the Sonoma Coast AVAs are also cooled by the marine incursion (such as that shown here on the McEvoy Ranch) at the low point in the coastal range called the Petaluma Gap, only the area within the Petaluma Gap AVA maintains a persistent wind of at least 8 mph throughout the growing season. It is known that wind of at least 8 mph causes the stomata of grape leaves to close, thus slowing respiration of acidity. Some believe continual wind exposure also increases skin thickness.
Additionally, the cooling effect of the wind prolongs the growing season and reduces yields. Wines of the Petaluma Gap AVA are often seen to have ample structure with resplendent acidity and plenty of flavour at lower alcohol levels than wines from the neighbouring portions of Sonoma County.
The initial petition for the Petaluma Gap AVA was submitted by the PGWA in February 2015, followed by the complete application in October 2016. The final ruling approving the AVA was posted by the TTB today.
The new Petaluma Gap AVA includes around 4,000 planted acres (1,620 ha) in the 200,000-acre region. It is unclear how much more of the AVA is plantable. Much of it is unsuitable for grapevines due to a variety of conditions including environmental protections, inappropriate soil types or lack of water. Around 80 growers own vineyards in the area, and there are nine wineries within the AVA. Three-quarters of the vineyard land is planted to Pinot Noir. The remaining planted acres are given over equally to Chardonnay and Syrah, with less than 1% growing a mix of other varieties. Grapes from the Petaluma Gap AVA are sold to wineries throughout northern California.