How do Napa wineries produce so many different world-class wines? Besides the nearly perfect weather condition for grape development, another principal reason is the diversity of Napa Valley’s topography.

Vineyards on the “floor” of the Napa Valley AVA (American Viticultural Area) thrive at slightly above sea level on average. In contrast, vineyards in the surrounding higher-level hillside vineyards can range up to 2600 feet in elevation.

Given the variety of soils, microclimates, and the range of elevations created during its geological history, the Napa Valley AVA is currently made up of 16 official “nested” AVAs that produce a broad range of grape varieties. Each vineyard offers distinct characteristics and styles as elevation differences affect the amount of sunlight exposure, fog prevalence, temperature variances, and even moisture levels.

As a result, a specific wine varietal, say Cabernet Sauvignon, made with grapes from a “floor” vineyard, may have decidedly different characteristics than one from one of the elevated vineyards.

Comparing a Floor Level AVA with a Hillside AVA

Overall, Napa Valley enjoys a Mediterranean climate that features mild temperatures with warm days and cool nights perfect for the constant and gradual ripening of the grapes.

However, the vineyards developed along the surrounding hillsides and mountain slopes experience different temperature profiles.

To illustrate, here are descriptions of two nearly adjacent AVAs, Yountville and Atlas Peak, that produce grapes at different elevations:

  • Yountville AVA: A Napa Valley “floor” AVA, the Yountville AVA vineyards range from 20 to 200 feet above sea level. The Yountville AVA vineyards enjoy moderate weather with influences from frequent early morning fog and cool mornings. Summer temperatures typically reach above 90°F while nighttime temperatures drop to the mid-50s.
  • Atlas Peak AVA: At 760 to 2600 feet above sea level, Atlas Peak vineyards are situated above the morning fog and enjoy cooler summer daylight highs near the 80°F range that yield lesser day-to-night temperature changes than on the floor of the Valley.

Where is the “Floor” of Napa Valley?

Of the sixteen nested AVAs, precisely one-half lie within the narrow northwesterly 35-mile-long valley between San Pablo Bay to the border of Lake County in the north. According to Wine Inspector, the eight “floor” AVAs from North to South are Calistoga, St. Helena, Rutherford, Oakville, Yountville, Stag’s Leap, Oak Knoll, and Coombsville.

It should be noted that the Cabernet Sauvignons from Napa Valley floor vineyards were the wines that made Napa Valley wines eventually world-famous. The first vineyard was planted on the Valley floor near today’s Yountville in 1836.

Mountain-Grown vs. Valley Floor Grapes

Vineyards on the Valley floor tend to produce higher yields than those on the hill and mountainsides. Those grapes on the Valley floor are generally larger, while mountain-grown fruit tends to be smaller and more intense with higher tannin levels. With mountain grapes, the challenge for these Napa wineries and winemakers is to mitigate the higher skin-to-juice ratios to create a smoother flavor.

Along the Valley floor, the vineyard manager’s challenge tends to focus on canopy management. Because of the heat and direct sunlight on the vines, maintaining the optimal canopy by selective trimming protects the grapes and encourages their maturation. If too much of the canopy is cut away and the vine receives too much sun exposure, the grapes will not develop properly and will dry up.

Explore Napa Vineyards with Platypus Wine Tours

Professional, safe, and well-organized Napa Valley wine tours with Platypus Wine Tours are the best way to explore and learn all about the art and science of wine production. You and your group will be treated to a carefully curated tour and wine tasting at some of the best Napa wineries. You may opt for a join-in tour or work with Platypus Wine Tours to customize a private or group tour to match your preferences.

Learn and enjoy while leaving the driving and introduction to experienced Platypus professionals.

For more information, visit the Platypus Wine Tours website.

Or, you may phone Platypus at 1-707-253-2723.