Glossary · Fermentation
Fining
Definition
Adding an agent that binds haze-forming material and drags it out of suspension, so that the cider clears without filtration. Bentonite, gelatine, isinglass, chitosan and silica sol are common.
- Subject
- Fermentation
In more detail
Fining agents work by charge and by binding: bentonite is a negatively charged clay that removes proteins, while gelatine and isinglass are positively charged proteins that remove excess tannin and the haze it forms. Because they work in pairs, over-fining with one commonly requires the other, and over-fining strips flavour along with haze.
Several traditional finings are animal-derived, which affects vegan labelling even though the agent is removed from the finished drink.
Where this is covered properly
The glossary defines; these pages explain. Each is described in its own words.
Related terms
Terms that belong to the same part of the subject, or that this one is routinely confused with.
Fermentation
Filtration
Passing cider through a porous medium to remove suspended solids, yeast and haze. Coarse filtration polishes appearance; fine filtration approaches microbiological stability.
Faults
Protein haze
A haze formed when proteins and phenolics combine, often appearing after a temperature change in bottle. It is prevented by bentonite fining and by cold stabilisation before packaging.
Chemistry
Tannin
In cider usage, the phenolic material responsible for bitterness and astringency, principally condensed tannins — procyanidins — built from catechin and epicatechin units.
Fermentation
Cold stabilisation
Chilling cider close to freezing for a period so that unstable material — potassium salts, protein-tannin complexes and colloids — precipitates in the tank rather than in the bottle.
Faults
Pectin haze
A persistent, fine haze caused by pectin remaining in suspension. It does not settle, does not respond to fining and is cleared only by pectolytic enzyme.
Where to go next
- Cider glossary — The whole vocabulary, by subject and A–Z.
- Comparisons — Terms that are only really clear when set against the thing they are not.
- Search — Finds terms by their aliases and by their spellings in other languages.
Sources
What this page rests on. Where a source is marked as registered rather than read, CiderHQ is recording that the body is authoritative on the subject without claiming to have worked through the document itself. See our evidence policy for what each state means.
Cider and perry production technical training material
Peter Mitchell / Cider and Perry Academy · reference work · registered as competent for this subject
Searched again on 2026-08-25 and it remains the one printed source here that a bibliographic check cannot fix, because it is not a published work with an edition. It is course material issued to participants of a training programme, so there is no catalogue record to verify, no ISBN, and no lawful public copy. Its state stays `registered` for that reason rather than through inattention.
The Science of Cidermaking and associated technical writing
Andrew Lea · reference work · passage verified 2026-08-24
Written by a food chemist who worked at Long Ashton on apple phenolics. Unusual among specialist cider writing in that it is primary-research-adjacent: the author is describing work he did, and cites the literature. This is why it is registered at tier 1 for chemistry while a general cider book is not.