Glossary · Fermentation
Secondary fermentation
Definition
Any fermentation after the primary: the slow finishing of residual sugar, a deliberate refermentation in bottle or tank for carbonation, or a malolactic conversion by bacteria.
- Subject
- Fermentation
In more detail
The term is used loosely and can mean three different things, so it is worth stating which. In sparkling production it means the sugar-and-yeast refermentation in a sealed vessel that creates the carbonation; in cellar usage it often just means the slow tail of the primary after racking; in microbiological usage the malolactic conversion is a separate bacterial process that is not a fermentation of sugar at all.
Where this is covered properly
The glossary defines; these pages explain. Each is described in its own words.
Production
Secondary fermentation
Any fermentative event that follows the primary ferment — residual sugar refermenting, a deliberate second alcoholic fermentation, or the malolactic conversion of the maturation phase.
Production
Bottle conditioning
Carbonating cider by letting a second fermentation finish inside the sealed bottle, so the gas is generated where it is going to stay.
Related terms
Terms that belong to the same part of the subject, or that this one is routinely confused with.
Fermentation
Primary fermentation
The vigorous first phase in which the bulk of the sugar is fermented, usually over one to several weeks, marked by visible gas evolution and a rapidly falling gravity.
Fermentation
Bottle conditioning
Carbonating cider by fermentation inside the sealed bottle, either from primed sugar or from sugar left over from an incomplete ferment. The yeast deposit remains unless the bottle is disgorged.
Fermentation
Malolactic fermentation
The bacterial conversion of malic acid into lactic acid and carbon dioxide, which lowers total acidity, raises pH slightly and softens the drink. It is a bacterial process, not a yeast fermentation.
Fermentation
Priming
Adding a measured quantity of fermentable sugar at bottling or kegging so that a residual yeast population produces carbon dioxide in the sealed container.
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.
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.