Standing on the top of Mt St Helena at the northern end of Napa Valley, looking north on a clear day you can see the volcanic cone of Cobb Mountain some ten km (six miles) to the northwest, the highest peak in the Mayacamas Mountains. Beyond it about the same distance lies Mt Konocti, the dormant volcano that looms ominously over the shores of Clear Lake, with Kelseyville in its morning shadow. These and other peaks, referred to locally as the Mountains of the North Coast, are where Lake County’s best wines grow.
Not just volcanic soils, but also topography define Lake County’s volcanic wines. These are ‘mountain wines’ in the truest sense, grown in some of the highest vineyards in California. Most of the county’s vines are planted above 500 metres (1150 feet), and some up to twice that. High elevation means drier and cooler, tempering the otherwise scorching temperatures for which Lake County is known. Cooling fog, so much a part of wine-growing elsewhere in California, is not a factor here, although cooler air masses occasionally drift in from the coast, keeping air moving and stripping out the worst of summer heat. Temperatures swing dramatically between day and night, hitting highs well over 35ºC (95ºF) before dropping off quickly to around 10ºC (50ºF) after the sun sets in the middle of the growing season.