The base beer is a Pilsner aged in Sauvignon Blanc barrels with the addition of Sauvignon Blanc grape juice for a secondary fermentation. The juice and barrels are from Dutton Vineyards in the Russian River wine appellation here in Sonoma County. There is no lactobacillus or pediococcus added to the beer, only brettanomyces. The tart acidity comes from the wine grapes.