Glossary · Chemistry
Sorbate
Also written potassium sorbate, sorbic acid. Each is a name for the same thing, which is why none of them has an entry of its own.
Definition
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.
- Subject
- Chemistry
- Also written
- potassium sorbate, sorbic acid
In more detail
Sorbate must be used with adequate sulphite. Without it, lactic acid bacteria metabolise sorbic acid to a compound that smells strongly of crushed geranium leaves — the geranium taint — which is irremediable.
Where this is covered properly
The glossary defines; these pages explain. Each is described in its own words.
Chemistry
Potassium sorbate
The soluble salt in which sorbic acid is actually added, used to hold sweetness in a bottled cider, and dangerous to use without sulphite because of what lactic bacteria do to it.
Fault
Geranium taint
A sharp, unmistakable crushed-geranium-leaf smell produced when lactic acid bacteria metabolise sorbic acid added as a preservative.
Related terms
Terms that belong to the same part of the subject, or that this one is routinely confused with.
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.
Fermentation
Sulphiting
Adding sulphur dioxide, usually as potassium or sodium metabisulphite, to juice or cider to suppress spoilage organisms, inhibit oxidation and enzymatic browning, and give a selected yeast a clear field.
Faults
Geranium taint
A pungent aroma of crushed geranium leaf, produced when lactic acid bacteria metabolise sorbic acid. It occurs when sorbate is used without adequate sulphite.
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.
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.
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.
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.