High Valley is an AVA in the larger Lake County AVA in California. It covers an area on the eastern side of Clear Lake, where the topography is crumpled and mountainous as a result of ancient lava flows. Dark, supple red wines made from Petite Sirah and traditional Rhone Valley varieties such as Syrah and Grenache are a particular specialty of the region.
The AVA fills a valley that stretches eastwards from the edges of Clear Lake. Vineyards are planted at high altitudes along the valley's surrounding ridges, and also on the more-sheltered valley floor. Cooling winds originating from Clear Lake are funneled through the valley throughout the growing season, making High Valley the coolest of the Lake County AVAs.
Vineyards in High Valley flourish on sites that reach between 1800ft and 2400ft (538m–740m) above sea level. The altitude, combined with cooling night-time breezes from Snow Mountain in the north, means there is a significant difference in day-time and night-time temperatures. This diurnal temperature variation effectively lengthens the ripening period of the grapes, letting them develop complex aromatics while retaining valuable acidity.
The dormant Round Mountain volcano that sits within the AVA is largely responsible for the topography and soil make-up of High Valley. Ancient lava flows have created the ridges where the vineyards are planted. The soils on these upper slopes have volcanic characteristics; shallow sand, gravel and tephra (small volcanic pebbles) are free-draining and make the vines work hard for water, leading to lower yields and greater concentration of flavor.
On the valley floor, lake winds and well-drained, alluvial soils create perfect conditions for the cultivation of white-wine varieties. Red-wine varieties tend to be planted on the higher ground, where they can benefit from the increased exposure to sunlight.
Some of Lake County's best vineyards can be found in the High Valley AVA. A wide variety of grapes are cultivated here, from the Rhone varieties and Petite Sirah to Sauvignon Blanc, Pinot Noir and Zinfandel.
