Glossary · Microbiology
Zygosaccharomyces
Definition
A genus of osmotolerant, highly sulphite-resistant yeasts, chiefly Zygosaccharomyces bailii, which can referment sweetened cider and concentrate despite preservative doses that stop other yeasts.
- Subject
- Microbiology
Where this is covered properly
The glossary defines; these pages explain. Each is described in its own words.
Microbiology
Zygosaccharomyces bailii
A preservative-resistant spoilage yeast that refements sweetened cider and juice, and one of very few organisms able to grow through sorbate and benzoate at cider strength.
Fault
Unwanted refermentation
Fermentation restarting in a sealed container, generating carbon dioxide that was not planned for and pressure that a bottle may not withstand.
Related terms
Terms that belong to the same part of the subject, or that this one is routinely confused with.
Faults
Unwanted refermentation
Fermentation restarting in a sealed container that was not intended to be conditioned, producing gas, haze, sediment and, in bottles, dangerous pressure.
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.
Chemistry
Sorbate
A preservative that prevents yeast from multiplying, used with sulphite to stabilise a back-sweetened cider against refermentation. It does not kill an active population.
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.
Cider
Concentrate
Apple juice from which most of the water has been removed, usually by vacuum evaporation, leaving a syrup of about 70 degrees Brix that is stable, transportable and reconstituted before use.
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.