Cosumnes River AVA

Cosumnes River AVA occupies the southwest corner of the Lodi AVA, situated between the towns of Walnut Grove and Thornton in Sacramento County. Interstate 5 forms the western boundary and California Highway 99 the eastern boundary. The AVA sits within California's Central Valley and takes its name from the Cosumnes River, which drains from the Sierra Nevada and meets the Mokelumne River nearby.

• Sub-appellation of Lodi AVA, located in Sacramento County
• Borders defined by I-5 to the west and CA-99 to the east
• Positioned in the southwest corner of the broader Lodi AVA between Walnut Grove and Thornton
• Named for the Cosumnes River flowing from the Sierra Nevada to join the Mokelumne River

Cosumnes River AVA is the coolest of Lodi's sub-appellations, a distinction driven by its proximity to the Sacramento-San Joaquin Delta and its near-sea-level elevations. Delta fog rolls in frequently at the low elevations found here, moderating temperatures throughout the growing season. This maritime-influenced climate sets the Cosumnes River AVA apart from Lodi's warmer interior sub-regions and creates conditions well suited to white wine varieties.

• Sacramento-San Joaquin Delta fog provides consistent maritime cooling
• Elevations of just 5 to 48 feet above sea level amplify fog influence
• Cooler than all other Lodi sub-AVAs due to low elevation and frequent fog
• Supports aromatic white varieties and cooler-climate wine styles

The soils of Cosumnes River AVA were a primary basis for the 2005 TTB petition that established the appellation. The dominant soil type is the San Joaquin series, characterized by reddish to yellowish brown sandy clay loam, two to six feet deep, sitting above a cemented clay or sandstone hardpan layer. Younger alluvial soils occupy the lower floodplain areas closer to the river. This hardpan restricts vine root depth, influencing vine stress and grape concentration.

• San Joaquin series soils: reddish to yellowish brown sandy clay loam, 2-6 feet deep
• Cemented clay or sandstone hardpan layer lies beneath the topsoil
• Younger alluvial soils found in lower floodplain areas near the Cosumnes River
• Soil distinctions, alongside climate, formed the basis of the TTB petition for AVA status

The cool, fog-influenced climate of Cosumnes River AVA favors white varieties, with Vermentino standing out as a particularly well-adapted grape. Red varieties including Cabernet Sauvignon, Merlot, and Zinfandel are also grown, along with Chardonnay and port varieties such as Touriga Nacional. The cooler growing conditions across this AVA produce wines with more freshness and aromatic definition than is typical of Lodi's warmer zones.

• Vermentino thrives in the cool, fog-influenced conditions
• Chardonnay and other white varieties perform well here
• Cabernet Sauvignon, Merlot, and Zinfandel represent the red grape plantings
• Touriga Nacional and other port varieties also cultivated in the AVA

Cosumnes River AVA was established in August 2006 following a petition submitted to the Alcohol and Tobacco Tax and Trade Bureau in 2005. The petition rested on demonstrable differences in soil type and climate compared to neighboring Lodi sub-regions. The AVA is the largest of Lodi's seven sub-appellations by total acreage at 54,700 acres, yet supports the smallest planted vineyard area at 3,500 acres. The nearby 1,450-acre Cosumnes River Preserve reflects the largely undeveloped natural landscape of the region.

• Approved August 2006, petitioned 2005, based on distinct soils and cooler climate
• One of seven sub-AVAs within the Lodi AVA
• Largest Lodi sub-AVA by total area; smallest by planted vine acreage
• Cosumnes River Preserve (1,450 acres) is located nearby