Glossary · Microbiology
Biofilm
Definition
A community of micro-organisms attached to a surface within a self-produced matrix, far more resistant to cleaning and to sanitisers than free-floating cells.
- Subject
- Microbiology
In more detail
Biofilms in hoses, valves, filler heads and the pores of wooden vessels are how a cider house reinfects successive batches from equipment that looks clean. Their existence is the reason sanitation protocols specify mechanical cleaning before chemical sanitising rather than either alone.
Related terms
Terms that belong to the same part of the subject, or that this one is routinely confused with.
Milling and pressing
Sanitation
The routine cleaning and disinfection of everything juice touches. In a cider house it is the single most effective control on spoilage, and it is separated into cleaning, which removes soil, and sanitising, which reduces the organisms left behind.
Microbiology
Acetic acid bacteria
Aerobic bacteria — *Acetobacter*, *Gluconobacter* and *Komagataeibacter* — that oxidise ethanol to acetic acid. They require oxygen, which is why they colonise surfaces, ullage and slack fittings.
Microbiology
Brettanomyces
A genus of slow-growing yeasts, *Dekkera* in its sexual form, that survive in wood and in finished cider and produce volatile phenols smelling of farmyard, leather, spice and sticking plaster.
Fermentation
Barrel ageing
Maturing cider in wood, either in neutral casks used purely as vessels or in barrels chosen to contribute oak, spirit or wine character.
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.
Peer-reviewed literature on cider fermentation microbiology
Various journals · peer-reviewed literature · registered as competent for this subject
Covers the microbial succession of spontaneous cider fermentation, the role of non-Saccharomyces yeasts in the early stages, malolactic conversion by Oenococcus and Lactobacillus species, and the organisms behind the principal spoilage faults.
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.