Glossary · Fermentation
Filtration
Definition
Passing cider through a porous medium to remove suspended solids, yeast and haze. Coarse filtration polishes appearance; fine filtration approaches microbiological stability.
- Subject
- Fermentation
In more detail
Filtration is rated by the size of particle retained. A sheet or plate filter at several microns removes visible haze; a membrane at 0.45 micron removes yeast and most bacteria and is the basis of sterile filtration. Each step also removes some colloidal material that contributes body and aroma, which is the argument traditional producers make against it.
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
Sterile filtration
Filtration through a membrane fine enough — conventionally 0.45 micron — to remove yeast and most bacteria, allowing a sweetened cider to be packaged without refermenting.
Fermentation
Fining
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.
Fermentation
Centrifugation
Clarifying juice or cider by spinning it so that denser solids are thrown outward and removed continuously. Faster than settling and used at scale in place of, or before, filtration.
Fermentation
Unfiltered
Packaged without filtration, so the cider retains yeast and colloidal material and is usually hazy. It is a process statement rather than a quality claim, and unfiltered ciders throw a sediment.
Equipment
Plate filter
A filter in which cider is pumped through a stack of cellulose sheets held in a frame, the sheet grade determining the fineness of filtration from coarse polish to near-sterile.
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.
Hochschule Geisenheim University — beverage technology
Hochschule Geisenheim · university · retrieved 2026-08-24
German beverage-technology research covering apple wine and fruit juice processing, including the enzymology of clarification.