Sensory descriptor
Geranium
The crushed-geranium-leaf note produced when lactic bacteria metabolise added sorbate — a fault with one cause and no remedy.
Also called Crushed geranium leaf, Pelargonium.
- Aroma family
- Floral
- Does it indicate a fault?
- No — a normal part of cider and perry aroma
What causes it
Potassium sorbate is added to prevent refermentation in sweetened cider, and it works by inhibiting yeast. It does not inhibit lactic acid bacteria. Where those bacteria are present and active, they reduce sorbic acid to sorbinol, which then dehydrates under acid conditions and rearranges to 2-ethoxyhexa-3,5-diene — a compound with an intensely geranium-like odour and a threshold around one hundred nanograms per litre. The reaction is irreversible, the compound cannot be removed, and the cider is unsaleable. It is entirely preventable by sulphiting adequately, or by filtering sterile, before sorbate is used.
There is no acceptable level. The compound’s threshold is so low that any detectable geranium note means the reaction has run, and unlike ethyl acetate or diacetyl it has no concentration at which it contributes anything.
The compounds responsible
Where the molecule is established. Some descriptors in this lexicon name a compound the compound register does not yet hold a record for; those are named in the cause above instead.
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.
Sorbic acid
A preservative that stops yeast but not bacteria, and whose effectiveness — like that of sulphur dioxide — depends on pH, because only the undissociated molecule works.
Lactic acid
The softer acid that replaces malic when malolactic fermentation runs, halving the acid a cider carries and changing its texture as much as its sharpness.
Sulphur dioxide
The antimicrobial and antioxidant on which most modern cidermaking depends, and whose effectiveness collapses as pH rises — which makes every sulphiting decision a pH decision first.
What raises it
Processes that increase this character, or preserve it where it would otherwise be lost.
Sorbate stabilisation
Adding potassium sorbate to prevent yeast from restarting a fermentation in the package — an inhibitor rather than a killer, and one that must never be used without sulphite.
Back-sweetening
Adding sugar, juice or concentrate to a cider that has fermented dry — a straightforward adjustment that leaves the drink microbiologically unstable until something is done about it.
Sulphite stabilisation
Managing free sulphur dioxide through maturation and at packaging so that a useful antimicrobial and antioxidant fraction survives into the bottle.
Sterile filtration
Membrane filtration at a rating that retains viable yeast and bacteria, which is what allows a sweet cider to be shelf-stable without heat or preservative — provided the filling that follows is aseptic.
The fault it points at
Meeting this descriptor above a certain intensity is how the fault below is usually noticed first.
Fault
A sharp, unmistakable crushed-geranium-leaf smell produced when lactic acid bacteria metabolise sorbic acid added as a preservative.
Where it is usually met
Fruit and styles this character is recorded in. A record here is where the descriptor is commonly found, not a claim that every example shows it.
About Geranium
Geranium taint is the clearest example in cider of a fault created entirely by an additive interaction rather than by neglect, and it catches producers who have done one part of stabilisation and not the other. Sorbate without sulphite in a cider carrying lactic bacteria is the standard recipe for it.
It is filed under floral because that is where the perception belongs — a taster meets a flower, not a chemical — but it is a fault in every style and context.
Others in the floral family
Blossom, rose, elderflower, hawthorn.
Apple blossom
A light, sweet floral note from terpene alcohols and 2-phenylethanol, distinct from the fruit character of the same tree.
Elderflower
A green-tinged floral note from terpene alcohols and cis-rose oxide, or from direct botanical addition.
Rose
The rose-petal note of 2-phenylethanol, a higher alcohol produced by yeast from phenylalanine.
Hawthorn
A heavy, faintly fishy hedgerow-blossom note from trimethylamine and phenylacetaldehyde in ageing cider.
Violet
A powdery floral note from β-ionone, formed by degradation of carotenoids carried in from the fruit.
What people ask next
Questions readers ask about the things this page mentions. Each one goes to the section that answers it rather than to a page written to receive the question.
- Does cider contain sulphites — Most does. Sulphur dioxide is added to protect juice and finished cider, and fermentation itself produces a small amount even when none is added. European labels must declare it above 10 mg per litre.
- How do i make my cider sweeter
- How do i sweeten cider without it fermenting again — Either remove or kill the yeast — sterile filtration or pasteurisation — or use a non-fermentable sweetener. Sorbate alone is not enough: it prevents yeast multiplying but does not kill what is already there, and needs sulphite alongside it.
- What is sweet cider in america — In the United States and Canada, sweet cider means fresh, unfermented, usually unfiltered apple juice, with no alcohol in it. In Britain the same phrase means a fermented cider with residual sugar.
- Why does cider contain lactic acid — Because malolactic bacteria converted the malic acid into it. Malic acid has two acid groups and lactic acid has one, so roughly half the titratable acidity disappears and the cider tastes softer.
- Does cider contain preservatives
Where to go next
- The sensory model — The thirteen structural dimensions and the twenty aroma families, in full.
- Compounds — The chemistry behind the words.
- Troubleshooting — When a perception turns out to be a problem, this is where it is diagnosed.
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.
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.
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.
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.