Cork is on the comeback trail in Wine Country. After using synthetic bottle closures for decades, Bay Area winemakers are returning to natural cork, the San Francisco Business Times reports. The possibility of tainted cork has led many producers to use synthetic caps over the years, but the technology for growing and testing cork has improved enough to mitigate the threat and draw companies back, St. Francis Winery & Vineyards CEO Christopher Silva told the publication. If the industry tide shifts back to a natural product, a cheers and a toast to sustainability might just be merited.