Biofine is a powdered preparation of purified isinglass (a type of collagen), isolated from the swim bladders of tropical fish. At the pH of beer, the collagen of Biofine has a positive charge which reacts with the negatively charged yeast cells and suspended solids, prompting flocculation. This accelerates the sedimentation process and produces a more compact, clearly delineated sedimentary layer at the bottom of the beer. The collagen binds with the yeast and other colloidal material in the beer, and is removed with the sediment. It does not remain in the beer. Biofine treatment makes clarifying beer quick and easy, significantly improves chill haze stability, and can also improve head retention in some beers.
To dose 5 gallons of beer, mix 0.025 oz of Biofine powder with 5 fluid oz of very cold water (ideally <40°F). Stir continuously for 30 min. Refrigerate for 2-4 hours, then stir for another 15 min. Do not allow the solution to rise above 60 °F, or the collagen will denature. Use of a blender is ideal, and can sometimes reduce necessary mixing to a single 15 min. step. Dose 5 gallons of beer with 1.9-4.5 fluid oz. of the solution, in a manner that allows effective mixing with the beer.