Covering a geographic area which includes the entire lake itself, Clear Lake is home to a number of smaller sub-appellations whose producers can choose either label for their bottles. Perhaps best known amongst these is [Red Hills AVA](/ava/red-hills-ava) - an appellation famed for its rich, concentrated and age-worthy wines made principally from the [Cabernet Sauvignon](/cabernet-sauvignon) grape. The upper lake region - as the name implies, the area at the northern end of the lake - is home to the most significant viticultural activity outside of the sub-appellations. Topography here is rugged and mountainous with vine rows planted on ridges above the water at elevations exceeding four-hundred metres. Grapes therefore enjoy excellent exposure to sunlight; the intensity of UV rays is amplified by the water’s reflective properties and the purity of the air across [Lake County](/county/lake-county), leading to thick-skinned, flavoursome grapes and subsequent well-balanced wines of phenolic intensity. Given the size of the lake around which the appellation is wrapped, it is no surprise that this AVAs climate is heavily influenced by the water. Cool breezes from its one-hundred-and-eighty square kilometres temper the afternoon heat, allowing grapes to thrive in an area that might otherwise be too warm. And the significant drop in temperature during the evening slows the ripening process, enabling complex flavours to develop whilst all important acidity is retained. The Mayacama Mountains and the nearby Mendocino Forest also have a profound influence on Clear Lake’s microclimate. Free-draining Manzanita loam - a gravelly, magnesium-rich red soil - is typical of many parts of the Clear Lake AVA. Mostly shallow and coarse, the soil forces vines deep in search of nutrients and hence contributes to a low yield of highly concentrated fruit. Since re-emerging as a serious wine region towards the end of the last century, [Lake County](/county/lake-county) and each of its sub-appellations have adopted a clear focus on producing quality wines with minimal environmental impact. The varietals of Clear Lake - elegantly structured [Cabernets](/cabernet-sauvignon), rich, intense [Zinfandels](/zinfandel) and crisp, refreshing [Sauvignon Blancs](/sauvignon-blanc) - continue to offer excellence at great value for the consumer.