New Zealand wines are on a hot streak. According to New Zealand Winegrowers, an industry trade group, exports are up 7 percent since last year, with the U.S. now it's largest market. Exports to the U.S. alone rose 13 percent. And as demand increases, New Zealand winemakers are rising to the challenge, providing an expanding selection of distinctive wines. Wine Spectator's MaryAnn Worobiec explains.