From there it extends south to the Santa Rosa Plains and Sebastopol and west to the towns of Monte Rio, Guerneville and Occidental.

[5] The Russian River is a rain-fed waterway that swells in the wintertime and provides vital irrigation to the region's vineyards during the dry season in late spring.

In the summertime, the warmth of the season is tempered by the maritime influence of fog that facilitates a long, slow ripening period and limits the risk of over ripeness or "baked" flavors in the grapes.

In 1997, the Russian River Winegrowers association attempted to expand the AVA all the way down to the town of Cotati in the southeast corner of Sonoma County.

In 2003, a new proposal was issued expanding the AVA 767 acres (310 ha) on the south western end near the Green Valley region.

Gallo contested that opinion and after changes in leadership the grower's associations officially takes a neutral stance on the proposal though some vocal opposition still exist.

Gallo's rival Kendall Jackson pumped more than $12 million into updating and establishing its La Crema label in the Russian River region.

While the region is predominantly associated with Chardonnay and Pinot noir, hillside vineyard locations have shown success with other varieties such as Syrah and Zinfandel.

[6] Within the AVA there are several microclimates that allow for suitable plantings of Sauvignon blanc, Gewürztraminer, Petite Sirah, Cabernet Franc and Merlot.

The region's cool climate produces more grapes with higher acidity that tend to be more balanced than the fatter, creamy style found in the Alexander Valley.

Grapes from the Russian River and smaller Green Valley areas have been prized by sparkling wine producers for their crispness and high quality.

Older clones planted in the mid to late 20th century, including the Martini, Swan, Pommard, and 115 clones, produced a "classic" style of Russian River Pinots that were characterized by vibrant (but pale) color, lively acidity, cherry and berry fruit flavors and delicate aroma that would often include earthy mushroom notes.

Other winemakers altered some of their viticultural practices in the vineyards, including adopting new trellising systems that allowed for more leaf removal which exposed the grapes to more sunlight.

In addition to enhancing some of the color producing phenols, the new trellising also served to increase sugar content (and subsequently alcohol levels) and decrease the amount of the green tasting pyrazine compounds found in the grapes.