Skirting the southwestern edge of Clear Lake, the Red Hills wine appellation is characterised by a dramatic landscape of volcanic hills and rocky ridges - remnants of tectonic activity over many thousands of years. Elevation is not surprisingly a key feature of the growing conditions here, with the overwhelming majority of vineyards occupying sites above six-hundred metres, and some plots situated up to nine-hundred metres above sea level. This altitude is integral to the celebrated fruit of Red Hills; elevated, well-exposed vines receive intense sunlight, with daytime temperatures moderated by cool Pacific breezes, and significant diurnal variation. Hence, the grapes here achieve optimal ripeness with greater tannins and strong acid retention. The broader climate of the region - like all [Lake County](/county/lake-county) appellations - can be described at warm and dry in summer and cold in winter, and as such the area requires only minimal use of pesticides. Red Hills’ soils are what gives this area its name. Striking in colour and volcanic in origin, these gravelly soils are rich in glassy black obsidian. They drain freely, forcing vines deep into the ground in search of sustenance, delivering low yields of small, intensely flavoured grapes and wonderfully concentrated wines. [Cabernet Sauvignon](/cabernet-sauvignon) is king here. This variety - the one that put [California](/region/california) on the wine map - is the darling of Red Hills’ winemakers and is vinified both as a premium mono-varietal wine as well as in blends with its [Bordeaux](/region/bordeaux) cousins [Cabernet Franc](/cabernet-franc), [Merlot](/merlot) and [Petit Verdot](/petit-verdot). These bold, structured wines are increasingly held in high regard by both critics and consumers, and are largely responsible for Red Hills’ reputation as [California’s](/region/california) ‘next big thing’. Other red varieties such as [Syrah](/syrah), [Zinfandel](/zinfandel) and [Cinsault](/cinsault) are also of note, and white wines are produced mainly from the [Sauvignon Blanc](/sauvignon-blanc) grape. The wineries here are small, bespoke operations and very often family-run; many of the more established cellars offer tastings and tours and sustainable viticulture is very much the expected practice.