Glossary · Fermentation
Arrested fermentation
Also written stopped fermentation. Each is a name for the same thing, which is why none of them has an entry of its own.
Definition
Deliberately stopping a fermentation before the sugar is exhausted, in order to retain natural sweetness. Achieved by repeated racking, chilling, filtration, sulphite, or a combination.
- Subject
- Fermentation
- Also written
- stopped fermentation
In more detail
The methods differ in how permanently they stop the yeast. Chilling and racking merely suppress it, so the cider must be kept cold or sterile-filtered before packaging or it will restart in the bottle. Sterile filtration removes the yeast; pasteurisation kills it. Keeving achieves the same end by starving the ferment rather than halting it.
Where this is covered properly
The glossary defines; these pages explain. Each is described in its own words.
Production
Arrested fermentation
Deliberately halting a ferment while sugar remains, to obtain natural sweetness from the fruit rather than from an addition — and accepting the instability that follows.
Production
Sterile filtration
Membrane filtration at a rating that retains viable yeast and bacteria, which is what allows a sweet cider to be shelf-stable without heat or preservative — provided the filling that follows is aseptic.
Related terms
Terms that belong to the same part of the subject, or that this one is routinely confused with.
Fermentation
Keeving
A pre-fermentation clarification in which pectin in the juice is gelled into a floating brown cap, taking nutrients and yeast with it, so that the clear juice drawn from beneath ferments slowly and stops with sugar remaining.
Fermentation
Racking
Transferring cider off its sediment into a clean vessel, leaving the lees behind. It is the basic maintenance operation of the cellar and the traditional method of slowing a fermentation.
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
Pasteurisation
Heating cider to destroy yeast and bacteria, either by flash pasteurisation before filling or by tunnel pasteurisation in the sealed container. It stabilises a sweetened product against refermentation.
Chemistry
Residual sugar
The fermentable sugar remaining in a finished cider, usually expressed in grams per litre. It is what sweetness legislation and style bands are written against.
Fermentation
Back-sweetening
Adding sugar, juice or concentrate to a fully fermented cider to reach a target sweetness. Because the added sugar is fermentable, the cider must then be stabilised or kept cold.
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.
The New Cider Maker’s Handbook: A Comprehensive Guide for Craft Producers
Claude Jolicoeur, Chelsea Green Publishing, 2013. ISBN 9781603584739 · reference work · bibliographic record verified, not opened 2026-08-25
Bibliographic record verified on 2026-08-25 against the Open Library union catalogue: Chelsea Green Publishing, 2013, ISBN 9781603584739, one edition recorded. That establishes the citation points at a real book in a stated edition, which is what a citation needs and is all it establishes. No copy was opened and nothing is quoted from it. The book itself is in print and not digitised in any open collection; where CiderHQ needs a figure from this territory it uses an accessible research source instead and says so.
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.