Temecula, california high desert wine region and ava inland of the coastal mountain range 35 miles north of San Diego. Temecula is the viticultural aspect of a mixed-use residential and industrial development called Rancho California. Beginning in the late 1960s, insurance company developers used vineyards as part of their sales pitch to urban-weary escapees from Los Angeles and San Diego. Rainbow Gap, a narrow opening in the coastal ridge, funnels cool marine air across a 5-mile swathe of sanded desert allowing grapes to be grown in what would otherwise be a deeply inhospitable home for vines. irrigation water is imported by pipeline. As the vineyards began to weave an image of moderate, salubrious weather, housing developments came swiftly to the undulating mesas all the way from Riverside south to San Diego. Within 20 years, grape-growers in the band of cool afternoon breezes at Temecula began to find themselves squeezed between rows of residences. Then viticultural disaster struck in the mid-1990s in the form of pierce’s disease infestation, forcing the removal of some 850 acres/344 ha of diseased vines by 2002. The region’s largest winery and grapegrower at the time, Callaway, had to resort to buying in grapes from elsewhere. Yet many took the opportunity to replant with varieties better suited to the conditions, among them heat-loving Grenache, Petite Sirah, Syrah, and Tempranillo. South Coast Winery is Temecula’s largest producer and grand experimenter with myriad varieties. Callaway rebounded under new owners, although on a much smaller scale and with mostly local grapes.