Visiting the Austrian wine regions of Kamptal, Krems and Wachau and meeting with winemakers in late May, I sensed both optimism and despair. When I toured the vineyards, the reason for the despair was obvious: Two nights of devastating frost in late April — a record cold snap that also struck Burgundy and Champagne in France and much of Germany’s wine regions — had destroyed 30 to 40 percent of the 2016 crop before it even had a chance. Rows of withered vines alternated with healthy ones, lost potential for a vintage that could still be terrific, if small. The optimism was in my glass every time I tasted a wine from 2015.