filtration
Fining
Add a substance that binds with haze-forming material and drags it out of suspension, clarifying wort or beer without filtration.
What is actually happening
Kettle finings — Irish moss and refined equivalents — carry a charge that flocculates protein during the boil, improving the hot break.
Beer finings, traditionally isinglass from fish swim bladders, carry the opposite charge to suspended yeast and pull it down. This is what drops a cask bright in a pub cellar in a day.
Isinglass is why traditionally fined cask beer is not vegan. Unfined beer is a presentation choice — slightly hazier, otherwise unchanged.
What goes wrong here
Risks rather than certainties. This step does not cause these faults; getting it wrong can.
- Permanent haze — Cloudiness that does not clear with warming, usually from incomplete starch conversion or irreversible protein complexes.
Related steps and concepts
- Cask conditioning — Where beer finings are traditionally used.
- Filtration — The mechanical alternative.
Also at the filtration stage
Centrifugation · Cold crashing · Filtration
See the whole process in order on how beer is made.
Last reviewed 2026-08-16.