Glossary · Microbiology
Non-Saccharomyces
Definition
A collective term for the yeasts other than Saccharomyces present in juice and early fermentation, including Hanseniaspora, Metschnikowia, Torulaspora and Pichia species.
- Subject
- Microbiology
In more detail
Once dismissed as spoilage, several are now used deliberately as co-inoculants for aroma, glycerol and mouthfeel, with a Saccharomyces strain added later to complete the ferment. The distinction between a useful non-Saccharomyces and a spoilage yeast is largely a matter of species, timing and oxygen.
Where this is covered properly
The glossary defines; these pages explain. Each is described in its own words.
Microbiology
Torulaspora delbrueckii
A non-Saccharomyces yeast that ferments further than most of its early-succession neighbours while producing notably little acetic acid.
Microbiology
Metschnikowia pulcherrima
An early-succession yeast that suppresses competitors by locking up iron, and is used commercially as a controlled non-Saccharomyces partner rather than as a fermenter.
Related terms
Terms that belong to the same part of the subject, or that this one is routinely confused with.
Microbiology
Apiculate yeast
Lemon-shaped, weakly fermenting yeasts — *Hanseniaspora* and its anamorph *Kloeckera* — that dominate the first days of a wild cider fermentation before alcohol suppresses them.
Microbiology
Wild yeast
Yeast arriving with the fruit and resident in the press house and its equipment, as opposed to a pitched commercial culture. The term covers both useful and spoilage species.
Microbiology
Microbial succession
The orderly replacement of one microbial population by another during fermentation, as rising alcohol, falling sugar, falling nutrient and falling oxygen change which organism can compete.
Faults
Film yeast
Aerobic yeasts, chiefly *Pichia* and *Candida* species, that grow as a dull white or grey film on the surface of cider in a part-empty vessel, metabolising ethanol and acids.
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.