The Feierling is an organic microbrewery on Gerberau, the narrow street that follows the canal in the Insel quarter. They brew their own unfiltered Inselhopf and a rotating seasonal beer in the cellar; the food is solid pub fare with a few vegetarian options.
In summer the beer garden across the canal — directly under the trees — is one of the most popular spots in town. You buy your beer inside, take it across the small footbridge, and sit at long shared tables. The atmosphere is unfussy and the regulars range from students to grey-bearded locals.