Guenoc Valley AVA

Guenoc Valley AVA - Lake County
The Middletown area sits on the elevated flanks of the Mayacamas Mountain range at an elevation ranging from 700 to 1500 feet above sea level. 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 winegrape varietals. The clear, warm days followed by crisp, cool nights combined with the mature Jafa rocky mountain soils on the slopes, well-drained deep Cole and Maxwell clay loams, and stratified alluvium soils on the valley floors make the Middletown area a premier winegrape growing region. Middletown has the distinction of having the oldest winegrape vines in California, dating back to the 1850s.

Topography The Middletown region lies within the North Coast AVA, south of Clear Lake and just north of Napa. Guenoc Valley is the only sub-appellation within the region and straddles the county’s southwestern border with Napa Valley. Middletown and Guenoc include both valleys as well as rolling volcanic formations and hills.
Elevation Vineyard elevations range from 700 to 1,500 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 grape skins, greater tannins, and intense wines with high phenolic content.
Soils The steep slopes and outcroppings of the Mayacamas Mountains guard the valley floors where many of the Middletown area vineyards have been planted. Most hillside soils are classified as Millsholm-Bressa loams. Millsholm, shallow and well-drained with 35% sandstone and shale fragments mixes with Bressa, a moderately deep well drained soil formed of weathered sandstone. In Guenoc Valley, Maxwell clay loam is common on valley floors. Langtry estate vineyards also enjoy well-drained deep Cole clay loams and Still stratified alluvium. Near Dry Creek Cutoff south of Middletown proper, mature, deep, well drained and somewhat rocky mountain soils can be found. Jafa primarily forms terraces and fans from varied sources.
Acerage 504 acres
Climate The Mayacamas Mountains determine the climate of the Middletown region. Temperature variations during the summer growing season are key to the region’s winegrowing success. Middletown and Guenoc’s daily temperature extremes in the summertime range from 100° plus in the early afternoon to the low 50s at night, making 45° to 50° diurnal swings, a common occurrence particularly in Middletown. Cold winters and dry summer conditions allow for low rates of pesticide and other applications.
Varietals Cabernet Sauvignon, Cabernet Franc, Merlot, Syrah, Zinfandel, Petite Sirah, Petite Verdot, Malbec, Grenache, Mourvedre, Tempranillo, Pinot Noir.

Lake County AVA Map

One-page overview of the Guenoc Valley AVA (PDF)

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