On tap at Ambulance, low-key dark sour ale aged two years in Leopold Bros. Whiskey barrels retains brettanomyces-bound balsamic vinegaring, tart oaken cherry pucker and mild lemon musk, but whiskey influence is negligible. Slight charcoal graze inundates sharp vinous sourness and horse-blanketed barnyard acridity by indirectly providing charred mocha remnant. Subtly complex.