Napa Valley is one of the most famous vintner locations worldwide, despite producing only 4 percent of wine in California and 0.4 percent of the world’s supply. The favorable soil and weather conditions that mimic the Italian Mediterranean climate are advantageous for winemaking and have given the region widespread acclaim. In the earlier days of winemaking, the effect of soil and climate differences weren't well understood, with wineries growing different grape sorts side by side. However, the industry has advanced, with expanding knowledge and technological advancements in recent decades. The various soil types and climate conditions around Napa Valley have allowed local vineyards to showcase the particular benefits of specific locations within the valley for certain grape varieties. Napa Valley is considered an AVA (American Viticultural Area), gaining that status in 1981, but has 16 smaller AVAs nestled inside. The number of AVAs is evocative of the enormous potential this region has in delivering some of the best wines in the world. The southernmost AVA, Los Carneros, has primarily clay-based soil and is highly affected by the winds blowing inward from San Pablo Bay. With a cool temperature year-round, it specializes in Pinot Noir and Merlot wines. Coombsville and Wild Horse Valley are the furthest southeastern AVAs, with relatively low temperatures year-round. Both AVAs have primarily volcanic soil, which is incredibly fertile. Coombsville wineries specialize in Cabernet Sauvignon, Merlot, Chardonnay, Pinot Noir, and Syrah wines. Wild Horse Valley’s altitude and lack of water retention make it more demanding to grow grapes in, with Pinot Noir and Chardonnay specialties of this AVA.

1. The Diversity in Napa Valley AVAs
Antoine Chaya

2. Introduction
Napa Valley is one of the most famous vintner locations worldwide, despite
producing only 4 percent of wine in California and 0.4 percent of the world’s
supply. The favorable soil and weather conditions that mimic the Italian
Mediterranean climate are advantageous for winemaking and have given the
region widespread acclaim.

3. In the earlier days of winemaking, the effect of soil and climate differences
weren't well understood, with wineries growing different grape sorts side by
side. However, the industry has advanced, with expanding knowledge and
technological advancements in recent decades. The various soil types and
climate conditions around Napa Valley have allowed local vineyards to
showcase the particular benefits of specific locations within the valley for
certain grape varieties.

4. Napa Valley is considered an AVA (American Viticultural Area), gaining that
status in 1981, but has 16 smaller AVAs nestled inside. The number of AVAs
is evocative of the enormous potential this region has in delivering some of
the best wines in the world.

5. The southernmost AVA, Los Carneros, has primarily clay-based soil and is
highly affected by the winds blowing inward from San Pablo Bay. With a cool
temperature year-round, it specializes in Pinot Noir and Merlot wines.

6. Coombsville and Wild Horse Valley are the furthest southeastern AVAs, with
relatively low temperatures year-round. Both AVAs have primarily volcanic soil,
which is incredibly fertile. Coombsville wineries specialize in Cabernet
Sauvignon, Merlot, Chardonnay, Pinot Noir, and Syrah wines. Wild Horse
Valley’s altitude and lack of water retention make it more demanding to grow
grapes in, with Pinot Noir and Chardonnay specialties of this AVA.

7. Eastern AVAs like Mount Veeder, Spring Mountain District, and Diamond
Mountain District spread across the western side of the Mayacamas
Mountains. These regions are generally cooler due to their elevation, with
varying soils based on altitude and proximity to the bay. These regions
typically grow Cabernet Sauvignon, Merlot, and Cabernet Franc varieties.

8. Centrally-located AVAs, including Oak Knoll District, Yountville, and Stags Leap
District, have moderately cool temperatures due to their proximity to the San
Pablo Bay. This allows marine air and fog to remain until late morning. Their
soil is a mixture of volcanic rock from the mountains and alluvial sediments.
These AVAs typically grow Cabernet Sauvignon and Merlot varieties, with Oat
Knoll District also known for its Riesling and Chardonnay.

9. Oakville, Rutherford, St. Helena, and Calistoga AVAs round out the AVAs east
of the Mayacamas. They are typically sweltering during the summer, with
temperatures often reaching above 100 degrees Fahrenheit. These regions
are primarily composed of volcanic rock near the mountain range, with
outward sections having a more rocky and stoney composition. Due to their
fertile grounds and warm climate, these AVAs have the most wine variations
in Napa Valley, with Cabernet Sauvignon, Cabernet Franc, Sauvignon Blanc,
Zinfandel, and Syrah being more popular in the north, with Merlot present in
southern sections.

10. The Howell Mountain, Atlas Peak, and Chiles Valley AVAs are somewhat
distant from the others on the eastern side of Napa Valley. Atlas Peak and
Howell Mountain are predominately volcanic, with the Howell Mountain being
the least fertile AVA. Wineries in these regions primarily grow hardy varieties,
but there is still some variety between them. The most popular wines from
these regions include Cabernet Sauvignon, Merlot, and Chardonnay.