The Zinfandel grape (formerly believed native, now revealed to be an immigrant) has long been made into rustic, bombastic wine suitable for Gold Country pioneers, where it was often grown. Now, of course, Zinfandel is more refined, with robust but elegant wines from producers like Grgich Hills, Ridge, Brown, Turley, and Saxon Brown, some going for as much as $100 a bottle. Still, there’s always a certain rowdiness (could it be the 16 percent alcohol?) at the annual Zinfandel Advocates & Producers Festival that makes it one of the most fun, if breathtakingly crowded, wine events in the San Francisco bay area. Come to Fort Mason in San Francisco on Saturday, January 31 to taste wines from around 275 producers, all neatly arranged in alphabetical order.