Cyrus Alexander - the pioneer after whom the appellation takes its name - was also the first to plant grapes here in the mid-nineteenth-century, and the first commercial winery was built in the region before the turn of the twentieth century. Prohibition, the great depression and World War II all had an impact on viticulture here but in the early 1970s Rodney Strong saw the potential of the valley’s terroir and planted six hectares of [Cabernet Sauvignon](/cabernet-sauvignon) vines. The resultant wine (1974 vintage) was much revered and laid the foundations for the premium varietals for which the area is now renowned. Alexander Valley’s climate is broadly Mediterranean with warm to hot summers and cool, wet winters. The proximity of the Pacific Ocean is an influential factor in ensuring that the grapes grown here develop a sound balance of flavour compounds and natural acidity. Marine air from the Petaluma gap moves northward through the valley tempering the daytime highs and the Russian River also has some impact on temperature moderation. Vineyards occupy sites from the valley floor to the benchlands and the southwest facing slopes of the Mayacama mountains, at elevations between one-hundred-and-fifty and almost eight-hundred metes above sea level. The benchlands in particular are associated with high quality, intensely aromatic [Cabernet Sauvignon](/cabernet-sauvignon), with free-draining, rocky soils and the perfect calcium-magnesium ratio proving ideal for the principal grape. Indeed, almost 80% of the AVAs grapes are concentrated in these areas. The Alexander Valley received official AVA status in 1984 and today covers a geographic area of some thirteen-thousand hectares. More than six-thousand of these are planted to vine with typical [Bordeaux](/region/bordeaux) red varieties accounting for around three-quarters of all production and [Cabernet Sauvignon](/cabernet-sauvignon) the undisputed king. Other notable reds include [Zinfandel](/zinfandel) and [Sangiovese](/sangiovese) whilst white wines are made from [Chardonnay](/chardonnay), [Sauvignon Blanc](/sauvignon-blanc) and [Viognier](/viognier). Typical Alexander Valley [Cabernets](/cabernet-sauvignon) are deep in colour and well-structured, with flavours of dark fruits, tobacco and herbs. Some of these wines are approachable in youth whilst others are meant for laying down in the cellar.