Lake County AVAs

Lake County contains a number of different AVAs, 9 in all. The largest of these is Clear Lake AVA which also contains 5 sub-region AVAs within it. The other 3 AVAs are separate but are also covered by the North Coast AVA.

Lake County wine is an appellation that designates wine made from grapes grown mostly in Lake County and located north of Napa County. Although each region within Lake County has unique viticultural attributes, all are influenced by Clear Lake, the largest inland body of water in California. Lake County enjoys a reputation for bright, concentrated red wines made from Cabernet Sauvignon, Syrah and Zinfandel, and fresh, aromatic whites made from Sauvignon Blanc. Cabernet Sauvignon has the most acreage, with Merlot a distant second.

Big Valley District-Lake County AVA

Established as an AVA on October 1, 2013.  The Big Valley District AVA viticultural area is located south of the southern shore of Clear Lake. It covers approximately 11,000 acres.  Big Valley was the first settlement in Lake County and has a long history of agricultural activity.  The boundaries of this region include Clear Lake to the north, Mount Konocti and the Red Hills Lake County AVA to the east, Merritt Road and Bell Hill Road to the south, and Highland Springs Road to the west.

Bordered by Clearlake on the north, the Mayacamas on the west and south, and Mount Konocti on the east, Big Valley is a structural basin that is part of the larger Clear Lake basin.

Warms days are moderated by the thermal mass of Clear Lake. Afternoon breezes carry down from the ridges of the Mayacamas and initiate afternoon cooling that often results in 50° diurnal cycles, key to retaining acidity in mature wine grapes. Cold winters and dry summers allow for low rates of pesticide and other applications.

Vineyard elevations range from 1,330 to 1,440 feet in Big Valley. Higher elevations and Lake County’s pure air allow for greater levels of UV light, as much as 10% more than neighboring sea level valleys. This UV intensity triggers thicker skins, greater tannins, and intense wines with high phenolic content.

Runoff over millennia have eroded the Mayacamas’ young volcanic foothills of Kelsey Bench into the ancient clays and deposits of Big Valley on the shores of Clear Lake, North America’s oldest lake, estimated to be two and a half million years old. Big Valley’s mix of gravel, clay and loam, bright sunlight from the 1,400 feet elevation, and cool nights produces remarkable Sauvignon Blancs, establishing Lake County as one of the premier California regions for the varietal. Along with the volcanic Kelsey Bench, the gravel seams in Big Valley produce intense and balanced Zinfandels and Cabernet Francs.  The evolving watershed has eroded into the fertile blocks of clay and loam soils of Big Valley, resulting in swaths of gravel deposits and well-drained soils.

Big Valley growers were among the first visionaries to discover the region’s wine grape potential and began planting vineyards in the 1960s, the first in Lake County since Prohibition.

Sauvignon Blanc is the most widely planted varietal in this area.  The other common varietals planted in the area are Chardonnay, Viogner, Riesling, Cabernet Franc, Zinfandel and Merlot.

Big Valley District-Lake County AVA had six bonded wineries, 43 vineyards, and roughly 1,800 acres cultivated at its official recognition.

High Valley AVA

Established as an AVA on June 30, 2005. The High Valley AVA is located in the eastern part of the county and situated above the northeast shores of Clear Lake in Lake County, this distinct growing area is defined by steep mountain ridges rising up to 3,000 feet directly from this hanging valley’s floor at 1,700 feet. Approximately nine miles long and three miles wide, this rare east-west transverse in the Californian coastal range was created by volcanic activity of Round Mountain.

Red volcanic soils can be found on the hillsides while alluvial fans and benches on the valley floor provide well-drained beds for the vines.  The distinct watershed boundaries of this region determine that soils found within the High Valley area are derived only from parent material found within the basin. Brick-red volcanic cinders and pumice-like gravel and stones allow for superior drainage. The western edge and middle of High Valley are composed of gravelly loams created from eroded Franciscan shales.

Appropriately named, this area’s high hanging valley ringed with steep volcanic hillsides produces mountain fruit with great color and structure.  Elevation along with the cooling effects of Clear Lake create a natural and perpetual “wind machine.” During July and August, daily temperature swings of 50 degrees are not uncommon. This intense cooling effect promotes good acidity, improved tannic structure, darker color, and more concentrated fruit character.

Higher elevations and Lake County’s pure air allow for greater levels of UV light, as much as 10% more than neighboring sea level valleys. This extra UV triggers thicker grape skins, greater tannins, and intense wines with high phenolic levels.

Main varietals are Cabernet Sauvignon, Cabernet Franc, Merlot, Syrah, Zinfandel, Petite Sirah, Petite Verdot, Malbec, Grenache, Mourvedre, Tempranillo, Pinot Noir.

Kelsey Bench-Lake County AVA

Established as an AVA on October 1, 2013.  The Kelsey Bench area encompasses about 9,100 acres The term "bench" was selected to reflect the topography of the area with higher elevations and hills.  The boundaries of the Kelsey Bench AVA are the Big Valley District AVA to the north, the 1,600 feet elevation line that runs east of Kelsey Creek to the east, Kelsey Creek Drive to the south, and Adobe Creek Drive to Highland Springs Road to the west.  Originally a pyroclastic lava flow, Kelsey Bench is a transition between the volcanic mountains and the alluvial flood plain. It has a largely northeastern exposure.

The Kelsey Bench and Big Valley AVAs are closely linked by geography, topography and history. As runoff caused the Mayacamas’ young volcanic foothills of Kelsey Bench to erode over millennia, the ancient clays and deposits of Big Valley formed on the shores of Clear Lake, North America’s oldest lake, estimated to be two and a half million years old.

Warms days are moderated by the thermal mass of Clear Lake. Afternoon breezes carry down from the ridges of the Mayacamas and initiate afternoon cooling that often results in 50° diurnal cycles, key to retaining acidity in mature wine grapes. Cold winters and dry summers allow for low rates of pesticide and other applications.

Kelsey Bench vineyards are planted up to 1,600 feet. Higher elevations and Lake County’s pure air allow for greater levels of UV light, as much as 10% more than neighboring sea level valleys. This UV intensity triggers thicker skins, greater tannins, and intense wines with high phenolic content.

Rich soils cover a large portion of the Kelsey Bench with good drainage favorable to growing grapes.  Volcanic Kelsey Bench and the gravel seams in Big Valley produce intense and balanced Zinfandels and Cabernet Francs.  Kelsey Bench forms an arc of rich, red volcanic soils. The evolving watershed has eroded into the fertile blocks of clay and loam soils of Big Valley resulting in swaths of gravel deposits and well-drained soils.

The main varietals grown in the AVA are Sauvignon Blanc, Chardonnay, Viogner, Riesling, Cabernet Franc, Zinfandel and Merlot.

The Kelsey Bench-Lake County AVA had 900 acres of cultivation, one bonded winery and 27 vineyards when it was officially recognized.

Red Hills Lake County AVA

Established as an AVA on July 11, 2004.  The Red Hills Lake County AVA lies along the southwestern shores of Clear Lake, separating Excelsior Valley to the east from Big Valley to the west. The hills lie at the foot of Mount Konocti, a volcano which last erupted 11,000 years ago, but which is still regarded as active. The terrain is rolling hills with elevations between 1,400 feet and 3,000 feet above sea level.

Located in the northern Mayacamas Mountains, the Red Hills of Lake County frame the southwest edge of Clear Lake. Comprised of dozens of volcanic hills ranging from 1,350 to over 3,700 feet above sea level, the appellation lies right over the North Coast Magna Pocket. As a result, the Red Hills are the latest formation of the volcanic and tectonic processes that created many of the famous hillside regions of the North Coast.

Vineyard elevations range from 1,350 to 2,600 feet with the majority of the AVA’s acreage planted at or over 2,000 feet. Higher elevations and Lake County’s pure air allow for greater levels of UV light, as much as 10% more than neighboring sea level valleys. This UV triggers thicker grape skins, greater tannins, and intense wines with high phenolic content.

Volcanic origin from neighboring Mount Konocti, producing well-drained vineyards rich in black obsidian, quartz crystals and volcanic gravel content, and strikingly red in color. Three general soil types predominate: Glenview-Bottlerock- Arrowhead, Konocti-Benridge, and Collayomi-Aiken.

With vineyards starting at 1,350 feet and reaching up to 2,600 feet above sea level, Red Hills of Lake County grapes are grown in mountain climate conditions. Upper level airflows from the Pacific Ocean combine with many local convections to moderate daytime highs. Low relative humidity and varied topography permit quick radiative cooling of ridgetop vineyards in the late afternoon and evenings. Both factors allow for good acid retention during ripening. Cold winters and dry summer conditions are an important factor in Lake County’s reduced pesticide and other application rates, one of the lowest in California.  The dramatic high elevation volcanic hillsides producing intense mountain fruit with great color and structure.

The main varietals grown in this AVA are Cabernet Franc, Cabernet Sauvignon, Petite Syrah, Sauvignon Blanc, Syrah, Zinfandel.

Upper Lake Valley AVA

Established as an AVA on June 2, 2022.  The topography of the Upper Lake Valley AVA defines a series of valleys running north-northwesterly from the shores of Clear Lake. These valleys and the surrounding hillsides sit at elevations of 1,330 to 1,480 feet and are slightly cooler than the surrounding areas.  The AVA, situated on the north shore of Clear Lake, covers a total of 17, 360 acres and is located entirely within the existing Clear Lake AVA.

The area—a transitional region between the Mendocino National Forest and the Clear Lake Basin—has a uniquely high water table (the boundary between the surface and the area where groundwater saturates the soil). This allows for a high degree of dry farming.

The climate of the Upper Lake Valley AVA is slightly cooler than the surrounding areas. The median growing degree days (GDD) in the new AVA ranges from a low of 2,809 to a high of 3,343; in other areas of the Clear Lake AVA, the median high climbs as high as 3,811.

The area contains a wide range of soil types, and varies decidedly between the deep, level soils of the valley floors; the thin, well-drained soils on the hillsides; and the marshy areas closest to the lake. Much of the bedrock is composed of shale and sandstone; topsoils include combinations of silt, gravel, clay, and loam.

The vineyards are currently planted along the valley floors and up into the hillsides—as high as 1,450 feet.  While a range of grapes—including Cabernet Sauvignon and Zinfandel—are grown in the area, Sauvignon Blanc is the leading variety.

At last count, there were sixteen commercial vineyards, just over 300 acres planted to vine, and one winery located withing the Upper Lake Valley AVA.

The other AVAs within Lake County:

Benmore Valley AVA

Established as an AVA on October 17, 1991.  The Benmore Valley AVA was named after Benjamin Moore, a local 19th century cattle rustler. The valley is a high depression in the mountains of southwestern Lake County, and is much cooler than surrounding areas.  The Benmore Valley AVA is a tiny, mountaintop wine region, at 2,400-2,700 feet, covering just 1440 acres of land in the south-west of Lake County, two hours' drive north of San Francisco.

The Benmore Valley AVA is significantly cooler than neighboring areas with little coastal influence and no fog. The region is the recipient of an annual average of 40-50 inches of rain.

The appellation contains mostly alluvial (Manzanita loam) soils.

Chardonnay was the grape of choice when the appellation was formed.  However, difficult growing conditions mean that, according to the Lake County Winegrape Commission, as of February 2018, there are no reported vineyards planted in Benmore Valley.  Frost here is a real danger to vines, and the cool summers and short growing season mean that it was a struggle for grapes to reach their full phenolic potential.

The fertile soils are not ideal for the production of quality grapes, and are better suited to other forms of agriculture.  Most of the grapes produced in the AVA were sourced by Geyser Peak Winery in Sonoma County.

Guenoc Valley AVA

Established as an AVA on November 18, 1981.  Guenoc Valley AVA was the first American Viticultural Area designation granted to an area with just a single winery.  Guenoc Valley is a small, inland AVA in the larger Lake County AVA and in the North Coast AVA. The area can be found just north of the Napa County boundary and roughly 15 miles south of Clear Lake.  The Guenoc Valley AVA area sits on the elevated flanks of the Mayacamas Mountain range at an elevation ranging from 700 to 1500 feet above sea level and covers an area of around 4,500 acres.

The Guenoc Valley AVA includes valleys as well as rolling volcanic formations and hills.  This mountainous wine region is one of the warmest in California. The Mayacamas mountains that lie between the valley and the Pacific Ocean create a rain shadow, making Guenoc Valley drier and hotter than the regions on the western side of the mountains.  Temperature variations during the summer growing season are key to the region’s winegrowing success. Guenoc’s daily temperature extremes in the summertime range from 100° plus in the early afternoon to the low 50s at night, making for 45° to 50° diurnal swings. Cold winters and dry summer conditions allow for low rates of pesticide and other applications.

The steep slopes and outcroppings of the Mayacamas guard the valley floors of the Guenoc, Collayomi and Long Valleys and serve to provide a variety of favorable grape growing sites for a select number of wine grape varietals.  The clear, warm days followed by crisp, cool nights combined with the mature rocky mountain soils on the slopes, well-drained deep clay loams, and stratified alluvium soils on the valley floors make the area a premier wine grape growing region.

Higher elevations and Lake County’s pure air allow for greater levels of UV light, as much as 10% more than neighboring sea level valleys. This UV intensity triggers thicker grape skins, greater tannins, and intense wines with high phenolic content.

Guenoc Valley is a small inland valley comprising an alluvial fan of loam series soils isolated from surrounding areas by rocky ridges.  The hilly terrain is largely volcanic in origin, and the shallow gravel and loam soils are well suited to the production of premium wines. Free-draining and rich in magnesium, these soils cause the vines to dig deep into the ground in search of sustenance, making them stronger and healthier. 

Careful site selection is vital due to the climate being relatively harsh for viticulture, and only the very best areas are chosen for cultivation.  Many vines are planted on ridgelines up to 1,400 feet above sea level to take advantage of the cooler environment that altitude brings.  Vineyards can also be found in the valley, where small, sheltered microclimates provide a cooler environment for the vines. The intense summer heat means grapes must be harvested early, before the sugars get too high and the acidity drops.

Petite Syrah, Cabernet Sauvignon, Sauvignon Blanc and Chardonnay are the most popular varietals planted here. The other varietals found here are Cabernet Franc, Merlot, Syrah, Zinfandel, Petite Verdot, Malbec, Grenache, Mourvedre, Tempranillo, and Pinot Noir.

Long Valley-Lake County AVA

Established as an AVA on July 4, 2023.  The Long Valley-Lake County AVA area of approximately 7,605 acres lies to the north and east of the established High Valley AVA.  The area inside the Long Valley-Lake County AVA consists of a long, narrow valley floor—situated at a medium elevation of 1,322 feet above sea level—surrounded by the hills of the High Valley Ridge and the Rocky Ridge. Long Valley Creek runs along the valley floor. The foothills and benchlands within the AVA rise an additional 200 feet to 500 feet above the valley floor.

The climate of the Long Valley-Lake County AVA differs from the climate of the surrounding areas in terms of annual rainfall as well as heat accumulation during the growing season. Rainfall in Long Valley averages between 27 and 33 inches per year, with the larger numbers typically experienced in the western edge of the area. These numbers are higher than those typically experienced in the areas to the south and east of the appellation, and quite a bit lower than those experienced to the northwest (where rainfall can average up to 45 inches per year).

The Long Valley–Lake County AVA sits atop the Cache Formation—an area of fossilized deposits left over from the Jurassic Period, when Lake County was covered by water. The Cache Formation—which forms basis of the area’s soils—consists mainly of freshwater lake deposits, volcanic rock, tuff (lithified volcanic ash), limestone, sand, and gravel. In many areas, these soils rest atop blue clay, limestone, and shale.

During the growing season, cool air blowing down from the hills helps to cool the vines from the heat of the day and allows some protection from early spring frosts. Elevation differentiates the Long Valley-Lake County AVA from the surrounding areas (such the High Valley AVA and Red Hills Lake County AVA); these areas have higher elevations and steeper hillsides.

The appellation covers approximately 149 acres currently planted with commercial vineyards; Cabernet Sauvignon, Cabernet Franc, Petite Syrah, and Syrah are the leading grape varieties.