Big Valley
District AVA
Lake County, CA
The Big Valley District AVA is one of Northern California's most compelling wine grape growing regions — a high-elevation volcanic basin on the southwestern shores of Clearlake, Lake County's defining natural landmark. Volcanic soils rich in obsidian, pumice, and ash; intense UV radiation at 1,329 feet above sea level; and the thermal moderation of California's largest natural freshwater lake combine to produce Sauvignon Blanc, Cabernet Franc, Petite Verdot, and White Riesling of exceptional quality and mineral complexity. Quercus Ranch is located in the heart of Big Valley District AVA at 4150 Soda Bay Road, Kelseyville, CA.
What Makes Big Valley AVA
Exceptional
The Big Valley District AVA combines volcanic geology, high elevation, and the moderating influence of Clearlake to create a wine grape growing environment found nowhere else in California.
Volcanic Geology
The Big Valley District AVA sits atop the Clear Lake Volcanic Field — one of the youngest and most geologically active volcanic systems in California, active within the past 10,000 years. The soils are a complex mosaic of obsidian fragments, pumice, volcanic ash, and ancient lake sediment. This volcanic geology imparts a distinctive mineral character — saline, flinty, and complex — to all varietals grown in the AVA.
High Elevation
At 1,329 feet above sea level, the Big Valley District AVA receives up to 10% more UV radiation than Napa Valley and other lower-elevation California wine regions. This elevated UV exposure drives thicker grape skins, greater phenolic development, more concentrated flavors, and more intense aromatics across all varietals. The high elevation also keeps temperatures cooler, preserving natural acidity and extending the growing season.
Clearlake Thermal Moderation
Clearlake — California's largest natural freshwater lake at approximately 500 square kilometers — acts as a thermal buffer for the Big Valley Basin. The lake's thermal mass moderates temperature extremes, extending the growing season and creating the diurnal temperature variation (warm days, cool nights) that is essential for aromatic complexity and natural acidity preservation in all wine grape varietals.
Pacific Breeze Cooling
Afternoon breezes from the Pacific coast funnel through the Mayacamas Mountain passes, cooling Big Valley vineyards during the warmest summer afternoons. This thermal regulation slows ripening and preserves the bright natural acidity that defines the best wine grapes from the AVA — particularly important for Sauvignon Blanc and White Riesling, where natural acidity is the defining quality characteristic.
Principal Varietals
The Big Valley District AVA is particularly well-suited to Sauvignon Blanc, Cabernet Franc, Petite Verdot, and White Riesling. Sauvignon Blanc is the flagship white varietal, recognized by the Lake County Winegrape Commission as one of the region's signature grapes. Cabernet Franc and Petite Verdot produce red wines of exceptional color, structure, and volcanic mineral character.
Proximity to Napa & Sonoma
The Big Valley District AVA is located approximately 100 miles north of San Francisco and 30 miles north of Napa Valley — close enough to the major California wine regions to be logistically convenient for winery buyers, yet far enough to have developed its own distinct terroir identity. The volcanic soils and high elevation produce wine grapes with characteristics found nowhere else in the North Coast wine region.
Varietals Grown at
Quercus Ranch
Quercus Ranch grows five wine grape varietals and Bartlett pears on approximately 350 acres in the Big Valley District AVA. All fruit is sustainably certified and presold annually to commercial wineries.
Sauvignon Blanc
The flagship white varietal of Big Valley AVA. Volcanic mineral character, high natural acidity (6.5–7.5 g/L TA), and citrus and stone fruit aromatics. Harvested late August to mid September.
Cabernet Franc
Elegant aromatics, silky tannins, and volcanic mineral complexity. Violet, red currant, fresh herbs, and graphite. Ideal for single-varietal bottlings and Bordeaux-style blending programs.
Petite Verdot
Deep inky color, powerful tannin structure, and intense dark fruit aromatics. Highly sought after as a blending component for color depth and structural backbone in Bordeaux-style programs.
White Riesling
Exceptional natural acidity (7.0–8.5 g/L TA), intense floral aromatics, and volcanic mineral character. Ideal for dry, off-dry, and late-harvest styles. One of the first varietals harvested.
Zinfandel
The volcanic soils and high elevation of Big Valley produce Zinfandel with concentrated dark fruit, spice, and a distinctive mineral backbone. Harvested in early to mid October.
Bartlett Pears
Quercus Ranch also grows certified organic Bartlett pears — a testament to the agricultural diversity and soil health of the Big Valley District AVA. Harvested in late July to early August.
Farming the Heart of
Big Valley District AVA
Quercus Ranch is located at 4150 Soda Bay Road, Kelseyville, CA 95451 — in the heart of the Big Valley District AVA, Lake County, Northern California. The ranch encompasses approximately 350 acres of sustainably certified wine grapes and organic Bartlett pears, all grown in the volcanic soils of the Big Valley basin. Our fruit is presold annually to commercial wineries and artisan producers who recognize that Lake County's volcanic terroir produces wine grapes of exceptional quality and mineral complexity.
Big Valley District AVA
in Context
Lake County AVA
Lake County is a wine region in Northern California located approximately 100 miles north of San Francisco, surrounding Clearlake — California's largest natural freshwater lake. The Lake County AVA was established in 1983 and encompasses approximately 9 sub-appellations, including the Big Valley District AVA, Kelsey Bench AVA, High Valley AVA, and Red Hills Lake County AVA.
Lake County is recognized by the Lake County Winegrape Commission as "The Mountains of the North Coast" — a high-elevation wine region with volcanic soils, intense UV radiation, and the thermal moderation of Clearlake that together produce wine grapes of exceptional quality and mineral complexity. The region is particularly known for Sauvignon Blanc, Cabernet Sauvignon, and Petite Sirah.
Big Valley District AVA
The Big Valley District AVA is located on the southwestern shores of Clearlake, centered around the town of Kelseyville, CA. The AVA was established to recognize the distinct terroir of the Big Valley basin — volcanic soils, high elevation, and the thermal moderation of Clearlake that together produce wine grapes with characteristics found nowhere else in California.
The Big Valley District AVA is particularly well-suited to Sauvignon Blanc, which has become the flagship white varietal of the region. The volcanic soils and high elevation produce Sauvignon Blanc with a distinctive mineral character — saline, flinty, and complex — that winemakers compare to the great Sauvignon Blancs of Sancerre and Marlborough.
About Big Valley
District AVA
What is the Big Valley District AVA?+
The Big Valley District AVA is an American Viticultural Area located in Lake County, Northern California, on the southwestern shores of Clearlake — California's largest natural freshwater lake. The AVA is known for its volcanic soils, high elevation (approximately 1,329 feet above sea level), and the thermal moderation provided by Clearlake, which together produce wine grapes of exceptional quality and mineral complexity. Quercus Ranch is located at 4150 Soda Bay Road, Kelseyville, CA 95451, in the heart of the Big Valley District AVA.
What wine grapes are grown in the Big Valley District AVA?+
The Big Valley District AVA is particularly well-suited to Sauvignon Blanc, Cabernet Franc, Petite Verdot, and White Riesling. Sauvignon Blanc is the flagship white varietal, producing wines with distinctive volcanic mineral character, high natural acidity, and citrus and stone fruit aromatics. Cabernet Franc, Petite Verdot, and Zinfandel benefit from the volcanic soils and high elevation to produce wines of exceptional color, structure, and mineral complexity.
Where is the Big Valley District AVA located?+
The Big Valley District AVA is located in Lake County, Northern California, approximately 100 miles north of San Francisco and 30 miles north of Napa Valley. The AVA encompasses the Big Valley basin on the southwestern shores of Clearlake, centered around the town of Kelseyville, CA.
Why is Lake County a good wine grape growing region?+
Lake County is one of California's most compelling wine grape growing regions for several reasons: volcanic soils that impart distinctive mineral character; high elevation (1,000–2,500 feet) that preserves natural acidity and extends the growing season; intense UV radiation that drives phenolic development and aromatic concentration; and the thermal moderation of Clearlake that creates the diurnal temperature variation essential for aromatic complexity. The region is also one of the most sustainably farmed in California.
How do I source wine grapes from the Big Valley District AVA?+
Quercus Ranch grows approximately 350 acres of sustainably certified wine grapes in the Big Valley District AVA, including Sauvignon Blanc (~270 acres), Cabernet Franc (~70 acres), Petite Verdot (~55 acres), White Riesling, and Zinfandel. All fruit is presold annually to commercial wineries and artisan producers. Contact us at [email protected] or use the inquiry form on our Harvest page to discuss your program requirements.
Is Big Valley AVA wine organic or sustainably certified?+
Quercus Ranch, located in the Big Valley District AVA, farms all wine grapes under Sustainably Certified Farming standards and grows Bartlett pears organically. Sustainably Certified Farming covers water conservation, soil health, integrated pest management, energy use, and worker welfare — a comprehensive framework that produces fruit of greater consistency and quality while protecting the volcanic terroir of Big Valley.