Does use of Isinglass require special mention on the beer? Isinglass is a fining - when added to beer it helps the beer clarify - and it's a form of collagen derived from fish swim bladders. 

Given that this is an animal-derived product, do breweries have to declare this on the packaging?
NO.

In 2003, the EC discussed requiring labeling for Isinglass as a potential food allergen.

The brewers in the EC successfully argued that it was part of the processing and not an additive and thus did not require labeling. 


  Isinglass finings are a tried and tested method of clarifying beer and so it came as a great relief to traditional cask ale brewers when the EC, last year, introduced an amendment to the 2003 labelling directive. The brewing industry successfully argued that as a processing aid, not an ingredient that would be consumed, and with a long history of use with no recorded incidents of an allergic reaction, there was a good case for isinglass to be exempt from the directive.