Glossary · Microbiology
Saccharomyces cerevisiae
Latin. Kept in its own language here rather than translated into the nearest English word, because the nearest English word is usually cut on a different axis.
Definition
The principal fermenting yeast of cider, beer and wine, tolerant of alcohol and of sulphite and capable of taking a cider to dryness. Most commercial cider yeasts are strains of it.
- Subject
- Microbiology
- Language
- Latin
In more detail
Strain choice within the species is a real variable: strains differ in cold tolerance, nitrogen demand, ester production, hydrogen sulphide tendency, flocculation and the killer factor by which some suppress others. Wine strains are commonly used for cider because their tolerance of low pH and low nitrogen suits apple juice better than brewing strains.
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.
Microbiology
Yeast
A single-celled fungus that ferments sugar to ethanol and carbon dioxide. Cider is fermented by a succession of yeast species, of which *Saccharomyces cerevisiae* usually finishes the job.
Fermentation
Inoculation
Adding a selected yeast culture to the juice to conduct the fermentation, usually after rehydrating dried yeast or building a starter.
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.
Fermentation
Attenuation
The proportion of the original sugar that fermentation has consumed, calculated from the fall in gravity from the starting to the current reading and expressed as a percentage.
Microbiology
Flocculation
The clumping together of yeast cells into aggregates that settle out of suspension. Highly flocculent strains drop bright quickly; powdery strains stay suspended and are harder to clear.
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.
Cornell Cider Research and Extension programme
Cornell University, School of Integrative Plant Science · university · passage verified 2026-08-24
Runs cultivar trials in New York State and publishes juice chemistry for European cider varieties grown in a North American climate — the single most useful counterweight to treating English figures as universal.