Terroir
Mendocino County is large, and due to two significant geographical features does not have a single, unifying terroir. The west side of Mendocino County is strongly influenced by the Pacific Ocean. Mountains dominate the western two-thirds of the county. Those two factors, and other topographical features, create significant differences in terroir between many of the county’s AVAs, though the entire county does have a Mediterranean climate.
The far western quarter is subject to cold air and fog from the ocean. Only areas high enough in altitude to be above the fog line are viable for even cool-climate viticulture. Just east of there, land is sufficiently isolated from direct ocean breezes to have hot afternoons. But a wind gap where the Navarro River meets the ocean allows for dramatically cooling winds and fog in the evening. East of that, there is a mountainous strip that sees even less Pacific cooling, but a couple of minor wind gaps do provide some relief. The far eastern quarter is relatively flat and effectively isolated from the Pacific. It’s the “banana belt” of Mendocino County and can ripen any grape variety you’d care to plant.
Location/Geography
Runs 20 miles (32km) SE-NW bestride Hwy 128, from the Yorkville Highlands to Navarro.
2,457 acres (994 hectares) planted.
Name Background
The valley is named for Walter Anderson who settled in the area, near present-day Boonville, in 1851
Topography/Elevation/Water Sources/Geographic Features
A narrow valley with few large, contiguous vineyards. Median vineyard size is 13 acres (5 hectares). Most are on slopes or benches.
Geology/Soil Composition
Alluvial, varying in depth and granularity with the grade.
Climate
Warm summer Mediterranean, cooled by fog and Pacific breezes.
Diurnal shift can be 40-50°F (4-10°C).
Main Grape Varieties
Pinot Noir, Chardonnay, Gewürztraminer, Merlot, Pinot Gris, Riesling
Location/Geography
Sits above the canyon through which Highway 253 runs, about five miles (8km) from Ukiah, and 13 miles (20km) from Boonville. Smallest AVA in the U.S. with just 189 total aces (76 hectares). 60 acres (24 hectares)) are under vine.
Name Background
Named for the vineyard’s original owner, John Cole. He bought the land in 1971.
Topography/Elevation/Water Sources/Geographic Features
1,400-1,600 feet (427-489 meters) altitude. The vineyard is contiguous and gently sloping.
Geology/Soil Composition
Alluvial clay loam and silt.
Climate
Warm-summer Mediterranean, cooled somewhat by altitude and Pacific breezes. Diurnal shift can be 50°F (10°C).
2,868 F degree days (1,576°C).
Hills shade the vineyard, allowing only nine hours of daily sun during peak growing season.
Main Grape Varieties
Riesling, Cabernet Sauvignon, Merlot
Location/Geography
An AVA of 4,563 acres (1,847 hectares), about 45 miles (72km) due north of Ukiah. It includes Round Valley, Williams Valley, and surrounding hills.
There are no wineries, just a single, two-acre (less than one-hectare) vineyard
Name Background
Named for the nearby town of Covelo.
Topography/Elevation/Water Sources/Geographic Features
Level topography.
Geology/Soil Composition
Very deep loam.
Climate
Four distinct seasons with high mountains blocking Pacific influence. The AVA petition therefore identifies the climate as Continental, but lack of non-winter rain doesn’t support that. The Köppen Climate Classification system says hot-summer Mediterranean.
Short growing season for the county, but higher than average daily temperatures.
Main Grape Varieties
Tempranillo, Pinot Noir, Grenache, Mencia
Location/Geography
An L-shaped AVA located at the junction of the Eel River and Middle Fork Eel River. The AVA is 15,000 acres (6,070 hectares) overall.
One winery with one six-acre (2.5 hectare) vineyard.
Name Background
Named for the “two rivers” that join there.
Topography/Elevation/Water Sources/Geographic Features
Vineyards are terraced on steep slopes.
Geology/Soil Composition
Rocky and low fertility.
Climate
Transitional, warm-to-hot-summer Mediterranean.
Main Grape Varieties
Cabernet Sauvignon, Merlot, Cabernet Franc, Zinfandel
Location/Geography
Immediately west of the Redwood Valley AVA.
It comprises 26,250 total acres (10,623 hectares). There are five vineyards, totaling about 120 planted acres (49 hectares).
Name Background
Named for a local mountaintop.
Topography/Elevation/Water Sources/Geographic Features
Ranges from 1,100 to 3,320 feet (335 to 1,011 meters) with rolling, steeply sloping terrain that offers southern exposures.
Geology/Soil Composition
Shallow and very well-draining Franciscan Complex sandstone and shale.
Climate
Warm-summer Mediterranean.
On average, due to Pacific influence, temperatures exceed 90° (32° C) in Eagle Peak Mendocino County only 22 times per year, as opposed to 64 times in Redwood Valley and 80 in Ukiah Valley.
Main Grape Varieties
Pinot Noir, Chardonnay
Location/Geography
Located southeast from the town of Hopland on Hwy 175 and nested within the Mendocino AVA.
2,250 acre (911ha) overall with 540 acres (219ha) planted.
Name Background
The valley is named for gold miner Paxton McDowell, who purchased the land out of a Spanish land grant in 1880.
Topography/Elevation/Water Sources/Geographic Features
Sloping benchland that rises to 1,000 feet (305 meters). Vineyards generally face west.
Geology/Soil Composition
Warm-summer Mediterranean.
Slightly cooler than surrounding areas due to altitude and cold air that slides down from the mountains at night, creating a dramatic
Main Grape Varieties
Zinfandel, Grenache, Syrah, Marsanne, and Viognier
Location/Geography
A 275,200-acre (111,289 hectare) V-shaped region in the county’s southern half. Six AVAs are nested within it: Anderson Valley, Cole Ranch, McDowell Valley, Potter Valley, Redwood Valley, and Yorkville Highlands.
Name Background
First use of the name Mendocino in the area was Cape Mendocino, named by Spanish explorers for Antonio de Mendoza, Viceroy of New Spain.
Topography/Elevation/Water Sources/Geographic Features
Flat to rolling, with room for contiguous vineyards of considerable size.
Geology/Soil Composition
Alluvial and often deep.
Climate
Warm-summer Mediterranean.
Main Grape Varieties
In the areas not covered by other AVAs: Sauvignon Blanc, Zinfandel, Syrah, Petite Sirah, Carignane, Charbono, and Grenache.
Location/Geography
Located in the coastal mountain range of southwestern Mendocino County. The AVA is 87,466 total acres (35,396 hectares) distributed within more than 250,000 acres (101,171 hectares) of forest. Eighteen vineyards combine for a collective total of 75 acres (30 hectares).
Name Background
The ridge is the AVA’s defining feature, though thought has been given to changing the name to Mendocino Coast.
Topography/Elevation/Water Sources/Geographic Features
Flat to steeply sloping ridgetops.
The only non-contiguous AVA in the United States, it has a minimum altitude of 1,200 feet (366 meters). Unlike other AVAs defined by altitude, there is no continuous ridge line.
Geology/Soil Composition
Well-drained, timber-type soils of varying depths.
Climate
Warm-summer Mediterranean, but cooler than most other Mendocino AVAs. Altitude, combined with all-day sun and no fog, compensates for lower temperatures.
Main Grape Varieties
Pinot Noir, Syrah, Zinfandel, and Albariño
Location/Geography
A 4,570-acre (1,922 hectare) region, roughly two-thirds of which is in southern Mendocino County. The rest of the AVA is in northern Sonoma County. There are approximately 400 acres (162 hectares) under vine in the AVA overall, most of that on the Sonoma side.
Name Background
Named for two significant peaks within the AVA.
Topography/Elevation/Water Sources/Geographic Features
Steep and undulating, with a minimum altitude of 1,600 feet (488 meters).
Geology/Soil Composition
Shallow and well-drained gravels, sandstone, and fractured shale.
Climate
Warm-summer Mediterranean
High altitude brings cooler temperatures on average throughout the year. This delays the start of the growing season by two weeks in most years. However, the vineyards are above the fog line and thus receive more morning and late afternoon sun.
Main Grape Varieties
Cabernet Sauvignon, Merlot, Cabernet Franc, Zinfandel, Chardonnay, Syrah, and Sauvignon Blanc.
Location/Geography
Sits on the northeast corner of the Mendocino AVA, and on the eastern edge of Redwood Valley. Of 28,805 total acres (11,657 hectares), 1,750 acres (708 hectares) are planted.
Name Background
Named for explorers William and Thomas Potter, who reached the area in 1852 and later settled there.
Topography/Elevation/Water Sources/Geographic Features
Primarily differentiated from Redwood Valley by altitude and is a minimum of 200 feet (61 meters) higher.
Geology/Soil Composition
Predominantly alluvial with some fluvial areas near streams.
Climate
Warm-summer Mediterranean with a very extreme diurnal shift.
Main Grape Varieties
Sauvignon Blanc, Chardonnay, Riesling, and Pinot Noir, plus a wide variety of Italian varieties.
Location/Geography
A 32,046 acre (12,969 hectare) AVA, north of the town of Calpella. It’s where Mendocino County’s first vineyards were planted. Today, there are about 2,750 planted acres (1,112 hectares).
Name Background
Mendocino County is famed for its redwood trees.
Topography/Elevation/Water Sources/Geographic Features
Primarily differentiated from Potter Valley by altitude, and is a minimum of 200 feet (61 meters) lower.
Geology/Soil Composition
Predominantly alluvial, some of it volcanic, with some fluvial areas near streams.
Climate
Warm-summer Mediterranean, with an extreme diurnal shift.
Main Grape Varieties
Zinfandel, Petite Sirah, Cabernet Sauvignon, and Barbera.
Location/Geography
Southern Mendocino County sits astride Highway 128 from the Sonoma County line to Anderson Valley in the northwest. Total acreage is 40,000 (16,187 hectares). Twenty-four vineyards combine for 414 acres (168 hectares) ranging in altitude from 850 feet to 2,500 (259-762 meters).
Name Background
Named for the community of Yorkville, founded in the mid-19th century by R.H. York.
Topography/Elevation/Water Sources/Geographic Features
Rugged, with many troughs and benches.
Geology/Soil Composition
Rocky and extremely well-drained.
Climate
Warm-summer Mediterranean, moderated by altitude and maritime fog. Diurnal shift is commonly 40-50°F (4-10°C)
Main Grape Varieties
Cabernet Sauvignon, Syrah, Pinot Noir, and Merlot