Sour beer is intentionally brewed with wild yeast, bacteria, or acidic ingredients to create tart flavors. Traditional Belgian examples include lambic, gueuze, and Flanders red ale. Modern American brewers experiment with kettle sours, Berliner Weisse, and fruited goses. Sour beers range from mildly tart to intensely mouth-puckering. They represent one of the oldest brewing traditions, now enjoying a craft renaissance.
