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supporting a proposed American Viticultural Area, or AVA, is submitted
to the government, which decides whether the proposed appellation
designation will be granted.
The Napa
Valley is itself an appellation. Within the Napa Valley
appellation exists 14 subappellations, or AVAs, including: Atlas
Peak, Chiles Valley District, Diamond Mountain District, Howell
Mountain, Los
Carneros, Mt.
Veeder, Oakville,
Rutherford,
St.
Helena, Spring Mountain District, Stags
Leap District, Yountville, Wild Horse Valley and Oak
Knoll District of Napa Valley. The Calistoga appellation is still
pending approval.
Atlas Peak
AVA
Climate: Cool,
mountain-influenced, with temperatures about 10 to 15°F cooler than
the Valley floor in summer. Above the fog line, there is a low diurnal
change, with summer temperatures rarely above 90°F (30°).
Elevation: 760 to 2600 ft (231m to 792m).
Rainfall: 38 inches (96 cm) annually.
Soils: Volcanic in origin, with basaltic red color, shallow with
limited water retention, so irrigation is often essential.
Principal
varieties & characteristics: Cabernet Sauvignon: Bright berry and
cherry fruit, and more acidity than wines from Stags Leap District.
Chardonnay: Crisp, flora, aromatic, with distinctive pear-mineral
flavors and bright acidity.
Chiles Valley
District AVA
Climate:
Fairly warmer summer days (mid-80°F plus), but due to higher
elevation and summer fog at night, quite chilly at night (below 50°F).
With colder winters and spring, as well as strong winds, harvest comes
later than on valley floor at Oakville.
Elevation: 800 to 1300 ft. (242 to 394m).
Rainfall: 35 inches (88cm) annually.
Soils: On the valley floor, primarily alluvial soils with silty-clay
composition of marine origin, with good fertility. Hillsides show more
clay-loam and stony-clay composition, mostly marine in origin, with
some volcanic outcropping, and less fertility.
Principal
varieties & characteristics: Cabernet Sauvignon, Merlot, Cabernet
Franc: Cabernets usually reveal a lush yet firm texture with good
acidity, firm tannin and distinctive cherry-blackberry flavors. Merlot
typically has vibrant black cherry flavors mixed with a touch of
cocoa.
Diamond
Mountain District AVA
Climate:
Moderately warm temperatures with lower maximum temperatures and
higher minimum temperatures than north Napa Valley floor, due to
topography and altitude. Significantly cooler than valley floor near
Calistoga, 50 to 95°F in growing season (10 to 32°C).
Elevation: 400 to 2200 ft. (130 to 530 m)
Rainfall: 40 to 55 inches (135cm) annually.
Soils: Residual uplifted soils of volcanic origin, often reddish and
very fine-grained, even gritty in texture, composed of both weathered
sedimentary and volcanic origin.
Principal
varieties & characteristics: Cabernet Sauvignon, Cabernet Franc:
firmly structured, rich and fairly tannic when young, with strong
blackcurrant, mineral, and cedary flavors. Less supple and fleshy than
valley or benchland wines, with good aging potential. Chardonnay:
Full-bodied, yet revealing mineral, green apple-peach aromas with
fairly firm acidity; less richly textured than valley floor wines.
Howell
Mountain AVA
Climate:
Similar to the facing Spring Mountain AVA, however slightly warmer and
dryer overall due to strong afternoon sun influence. Fairly cool
nights in both ranges and higher elevations help maintain good
acidity.
Elevation: 600 to 2200 ft (184 to 675m).
Rainfall: 40 to 50 inches (125cm) annually.
Soils: Predominantly volcanic, shallow and infertile. Drainage is
high, fertility low.
Principal
varieties & characteristics: Cabernet Sauvignon, Merlot,
Zinfandel: Powerful, firm, blackberry-currant flavors and often richly
tannic, with excellent acidity for aging. Chardonnay, Viognier:
Sinewy, firm and not as fruity as those of the valley floor, revealing
more citrus and stone fruit flavors.
Los Carneros
AVA
Climate: Cool,
with prevailing marine winds from the San Pablo Bay and through the
Petaluma Gap to the west. High temperatures during summer rarely
exceed 80°F (27°C) with less diurnal range variation.
Elevation: 15 to 400 ft. (4.6 to124 m)
Rainfall: Lowest in Napa Valley: 18 to 24 inches (7.2 to 9.6 cm)
annually.
Soils: Clay dominated, very shallow in general, with more loam and
hillside alluvials in the northern section. Yields typically are
restrained by the hard claypan subsoil, which prevents deep-rooting.
Principal
varieties & characteristics: Chardonnay: minerally pear-apple and
spice flavors.Merlot: sinewy and lightly herbal, with fine tannins and
sleek structure. Pinot Noir: ripe cherry-cinnamon spice flavors with
earthy notes.
Mount Veeder
AVA
Climate: Cool
to moderate, with most vineyards above the fog-line, meaning warmer
nights and cooler days and less diurnal range than the valley floor.
Typical mid-summer high temperatures about 85°F (30°C).
Elevation: 600 to 2100 ft. (183 to 650m).
Rainfall: 35 inches (87.5cm) annually.
Soils: Sedimentary based, former seabed, shallow and generally well
drained, as well as more acidic, with low fertility. Most have a sandy
or sandy-loam texture.
Principal
varieties & characteristics: Ageability is a hallmark of Mt.
Veeder wines. Cabernet Sauvignon, Merlot, Zinfandel: Low yields give
red wines a firm, tannic structure with strong earth-berry aromas and
rich, but powerful flavors. Chardonnay: minerally, appley, even citrus
flavors with good acidity.
Oak Knoll
District of Napa Valley AVA
Climate:
Moderate to cool: marine air and fog can remain until mid-morning.
Late afternoon breezes frequently occur, maintaining slightly cooler
temperatures than upper valley. Mid-summer temperatures may reach 92
degrees F (31.5 C) and drop to around 50F (10C) at night.
Elevation: sea level to 800 feet (244m)
Rainfall: 36 inches (90cm) annually.
Soils: The valley's largest alluvial fan formed by Dry Creek creates
the defining feature of the district. The northwest area is composed
of volcanically derived soils, with stony or gravelly consistency.
South and east areas are transitional from gravel to silty clay loam.
Principal
varieties & characteristics: Merlot, Chardonnay and Cabernet
Sauvignon. Merlot and Cabernet Sauvignon benefit from a longer growing
season with slightly cooler temperature, though crop size is typically
less than in other AVAs. Elegant style is the common note with fruit
flavors of cassis, tobacco and spice typical to Bordeaux-style reds.
Chardonnay showcases flavors of crisp apple, mineral notes and
tropical fruit with fine acidity.
Oakville AVA
Climate:
Moderately warm, with temperatures commonly in the mid-90°F range in
high summer, but also still strongly affected by night and early
morning fog which helps keep acidity levels good. East side of the AVA
receives more of warmer afternoon sun.
Elevation: 75 to 500 ft (23 to 150m).
Rainfall: 35 inches (87.5 cm) annually.
Soils: Primarily sedimentary gravelly alluvial loams on the western
side, with more volcanic but heavier soils on the eastern side. Low to
moderate fertility and fairly deep, with average water retention.
Principal
varieties & characteristics: Cabernet Sauvignon, Merlot: Ripe
currant and mint flavors, rich texture and full, firm structure
tempered by rich fruit. Sauvignon Blanc: Full, steely, yet very
fleshy, and not especially crisp.
Rutherford
AVA
Climate:
Moderately warm, still marginally influenced by early morning fog.
Western bench area is cooler, with less late afternoon sun, tempered
by afternoon marine winds. (This AVA averages a bit warmer than
Oakville and Stags Leap District). Usual summer peak temperatures are
mid-90°F with good diurnal range.
Elevation: 100 to 500 ft. (33 to 150m).
Rainfall: 38 inches (95 cm) annually.
Soils: Western benchland is sedimentary, gravelly-sandy and alluvial,
with good water retention and moderate fertility. The eastern side has
more volcanic soils, moderately deep and more fertile.
Principal
varieties & characteristics: Cabernet Sauvignon, Merlot, Cabernet
Franc, Zinfandel: This is "Cabernet country." Quite intense
cherry and mineral, almost earthy aromas. Flavors are full, ripe, and
notably currant with firm, but supple tannins for extended aging.
St. Helena
AVA
Climate: Warm,
due to greater protection from western hills, with less fog or wind
incursions. The narrowing of the valley floor provides more heat
reflection off the hillsides. Mid-summer temperature peak is often in
the mid- to high 90°F range (31 to 35°C).
Elevation: 150 to 600 ft. (46 to 185m).
Rainfall: 38 to 40 inches (95 to 100cm) annually.
Soils: South and west borders are more sedimentary, gravel-clay soils,
with lower fertility and moderate water retention. Further north and
to the east soils are prevalently volcanic in origin and are deeper
and more fertile.
Principal
varieties and characteristics: Cabernet Franc, Cabernet Sauvignon,
Merlot: deep, ripe, often jammy flavors, with firm tannins for
structure, and appealing aromas of currant and black fruit. Rhone
varieties (Syrah, Viognier): Fleshy, supple and slightly earthy.
Zinfandel: Blackberry-like, well-structured.
Spring
Mountain District AVA
Climate:
Similar to Mt. Veeder AVA, with cool weather prevailing and smaller
diurnal changes. Fairly cool nights and higher elevations help
maintain good acidity.
Elevation: 600 to 2200 ft (184 to 675m).
Rainfall: 40 to 50 inches (125cm) annually.
Soils: Primarily sedimentary; weathered sandstone/shale, loamy and
friable in texture. Drainage is high, fertility low.
Principal
varieties & characteristics: Cabernet Sauvignon, Merlot,
Zinfandel: Powerful, firm, blackberry-currant flavors and often richly
tannic, with excellent acidity for aging. Chardonnay, Viognier:
Sinewy, firm and not as fruity as those of the valley floor, revealing
more citrus and stone fruit flavors.
Stags Leap
District AVA
Climate:
Moderately warm, with afternoon marine winds acting as an
'air-conditioner' to cool the warmer air radiating off the bare rocks
of Stags leap itself and the surrounding hillsides. This AVA is often
up to 10& deg;F warmer than in Yountville AVA. Mid-summer
temperatures can reach 100°F, but more regularly are in mid-90 range
(32-34°C).
Elevation: 66 to 400 ft. (20 to 123 m).
Rainfall: 30 inches (75cm) annually.
Soils: Volcanic gravel-loams on the floor of the valley, with rocky
hillsides, and low to moderate fertility due to hard clay bedrock
subsoils 2 to 6 feet down.
Principal
varieties & characteristics: Cabernet Sauvignon, Merlot,
Sangiovese: Distinguished by lush, velvety textures and fine perfumed
cherry and red berry flavors, supported by soft tannins. Chardonnay,
Sauvignon Blanc: Round and ripe, especially Sauvignon Blanc, yet
retain excellent citrus and apple flavors.
Wild Horse
Valley AVA
Climate: A
warmer area well to the east of Napa Valley proper, but still
moderated by both altitude and prevailing winds coming off Suisun Bay
to the Southeast.
Elevation: Wild Horse Valley 400 to 1500 ft. (123 to 460 m).
Rainfall: 35 inches (94 cm) annually.
Soils: Volcanic in origin, with basaltic red color, shallow with
limited water retention, so irrigation is often essential.
Principal
varieties & characteristics: Cabernet Sauvignon, Sangiovese:
Bright berry and cherry fruit, and more acidity than wines from Stags
Leap District. Chardonnay: Crisp, flora, aromatic, with distinctive
pear-mineral flavors and bright acidity.
Yountville
Climate:
Moderate, with definite cool marine influence and fog contributing to
cool summer mornings and the marine breeze keeping afternoons more
comfortable than further up valley. Mid-summer peak temperatures may
reach 90°F (31°C), with noticeable diurnal fluctuation to the mid-50°F
range (13°C).
Elevation: 20 to 200 ft (6 to 61m).
Rainfall: 32 inches (80 cm) annually.<br
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