(BusinessWeek) - A new era for California’s priciest wine regions began Feb. 1, when PlumpJack Winery partners bought 50 acres in Napa Valley’s Stags Leap district, home to heralded vintners Shafer Vineyards, Clos du Val and Cliff Lede Vineyards. The purchase kicked off a sales spree for premium properties across the state that’s poised to climb to $800 million by year end, the most since the 2007 market peak, according to Demeter Group, a San Francisco-based consumer investment bank and advisory firm.