Fault
Framboise
A raspberry-and-rotten-fruit character with sulphurous overtones, produced by Zymomonas mobilis in sweet ciders that still contain sugar.
Also called framboisé, raspberry fault.
- Severity
- Serious — the batch may not be salvageable
- Where it starts
- Maturation, Blending, Stabilisation, Storage
- Can it be fixed?
- Partly — it can be reduced, not removed
- When you notice it
- Maturation, Storage
- Signs
- 5 recorded
What it is
Framboise, named from the French for raspberry, is a spoilage condition of sweet and medium ciders and perries caused by the bacterium Zymomonas mobilis. It produces an odd, sweetish raspberry or rotten-fruit aroma over a distinctly sulphurous base, along with haze and gas. It is uncommon but well recognised in traditional cidermaking, and it is specific to cider and perry among the fermented drinks, because the organism needs the residual sugar those styles carry.
What you notice
Grouped by sense, because that is how the fault presents itself rather than how it works.
On the nose
- A raspberry or soft-fruit smell in a cider that contains no raspberries
- A rotten or over-ripe fruit note underneath the raspberry
- A hydrogen sulphide edge alongside it — The combination of fruit and sulphur is the diagnostic pairing.
To look at
- Haze developing in a cider that had been clear
How the batch behaves
- Slow gas production in a sweet cider thought to be stable
The words for it: Raspberry. Each links to what produces it.
When it appears. In finished cider, usually in the warmer months and usually in a batch with residual sugar. The raspberry note develops over weeks and does not resolve.
The name is French and the fault is best documented in the French and Spanish cider literature, where the conditions that produce it — residual sugar in a warm cellar — are ordinary. It is a good example of a fault whose recognisability depends entirely on a taster having been told the word.
Various journals
What it is mistaken for, and how to tell
One observation per rival, chosen because it separates them rather than because it describes either. Several of these are not faults at all — a style feature, a normal outcome, or the fruit behaving as it does.
- Genuine berry aroma from a fruit cider — What went into it. A raspberry note in a cider with no fruit addition is this fault; in a fruit cider it is the product.
- Brett character — Both are microbial and both develop slowly in the bottle. Framboise is specifically raspberry and sits alone; Brett brings a whole family of phenolic notes.
- Lactic off-flavours — Framboise is a specific and recognisable berry character rather than the dairy and sour-milk range.
What is actually happening
The chemistry or microbiology behind it. Understanding the mechanism is what makes the prevention make sense rather than being a list of rules.
Zymomonas mobilis is an unusual bacterium: it ferments glucose and fructose to ethanol and carbon dioxide by the Entner-Doudoroff pathway, making it one of very few bacteria that produce ethanol as their main fermentation product. It is the organism behind palm wine and pulque, and in cider it behaves as a spoilage organism because it does that fermentation in a drink that was supposed to be finished.
Alongside ethanol it produces acetaldehyde and hydrogen sulphide, and it is that combination which gives the characteristic aroma. The raspberry impression is generally attributed to acetaldehyde interacting with the cider’s other components rather than to any single raspberry-smelling compound, and the sulphurous underlay comes from the hydrogen sulphide.
The organism requires glucose, fructose or sucrose; it cannot use malic acid or the other substrates that sustain lactic acid bacteria. This restricts it precisely to sweet and medium ciders and to perries, where sorbitol keeps a genuine sweetness even after complete fermentation. A fully dry cider does not support it.
It is sensitive to sulphur dioxide, which is the main reason it has become rarer as sulphiting has become routine, and it is favoured by high pH and warm conditions.
How it happens
| Cause | Stage | How often |
|---|---|---|
| Residual sugar in a sweet or medium cider held without effective protection | Maturation | occasional |
| Back-sweetening a cider that is not microbiologically stable | Blending | occasional |
| Little or no free sulphur dioxide in a high-pH cider | Stabilisation | occasional |
| Perry, where unfermentable sorbitol coexists with fermentable sugar for long periods | Maturation | rare |
| Warm cellar conditions during maturation of a sweet batch | Storage | rare |
Can it be put right?
Most cider faults cannot be reversed. Where that is the answer it is given plainly — an honest 'this batch is what it is' is more useful than a procedure that will not work.
| Option | Effectiveness | What it involves |
|---|---|---|
| Sulphite to stop the population where the fault is caught very early | Partial | The organism is sulphite-sensitive, so an appropriate addition halts progression. It does nothing about the character already formed, and the addition rate must come from supplier guidance for the measured pH. |
| Ferment the remaining sugar out to dryness | Unlikely to work | Removes the substrate for the future but leaves the fault, and must never be done in a sealed bottle or a closed container. |
| Blend into a much larger dry volume | Unlikely to work | The aroma is distinctive and persistent, and blending risks distributing the organism. |
| Remove the aroma from an affected batch | Not possible | The compounds cannot be selectively removed at any accessible scale. |
CiderHQ gives no additive dosage figures. An addition is a food-safety decision that depends on legal limits, on the juice in front of you and on what you are protecting against, and the right figure comes from your supplier’s or regulator’s own guidance rather than from a general reference.
Preventing it
- Do not leave a sweet cider unprotected; residual sugar is the condition the organism needs.
- Where a cider is back-sweetened, make a deliberate decision about stability — filtration, pasteurisation or an appropriate preservative regime — before it goes into a container.
- Maintain free sulphur dioxide at a level chosen for the measured pH, from supplier guidance and within legal limits.
- Keep maturation cool and vessels clean, particularly for sweet batches.
- Watch perry closely, since its natural sweetness makes it a standing invitation.
Framboise is a genuine curiosity in the fault literature: a spoilage organism that makes something smell of raspberries. It is rare enough that many makers will never meet it, and distinctive enough that those who do tend to remember it.
Its restriction to sweet ciders and perries follows directly from the biochemistry. Zymomonas mobilis is a sugar fermenter and nothing else, so a dry cider offers it nothing. That makes it a useful illustration of a general principle: every spoilage organism has a substrate, and knowing which substrate a cider still contains predicts which organisms it is exposed to.
Perry deserves particular attention here, because sorbitol gives perry a real sweetness even when fully fermented, and a perry maker can easily assume a fully attenuated drink is therefore microbiologically finished. The unfermentable sorbitol is not the problem; the fermentable sugar that may accompany it is.
The fault has become less common as sulphiting has become standard practice, which is a reasonable summary of its epidemiology: it is an organism of the unsulphited, sweet, farmhouse tradition rather than of a modern stabilised cidery.
The compounds involved
Acetaldehyde
The compound sitting one step short of ethanol, which smells of bruised apple and sherry, binds most of the sulphite added to a cider, and is the chemical signature of oxidation.
Hydrogen sulphide
The rotten-egg gas a nitrogen-starved yeast produces, detectable at concentrations too small to measure easily, and removable only if it is caught before it becomes something worse.
Glucose
The sugar yeast takes first and the smallest of the three in apple juice, which is why the last sugar left in a slow ferment is almost never glucose.
Fructose
The dominant sugar of apple juice and the sweetest of the common sugars, which is why apple juice tastes sweeter than its total sugar figure implies and why a stuck ferment leaves sweetness behind.
Ethanol
The alcohol yeast makes from fruit sugar, which converts a perishable juice into a keepable drink and carries most of its aroma to the nose.
Sorbitol
The unfermentable sugar alcohol that pears carry in quantity and apples carry only in trace, and the single reason a fully fermented perry keeps a sweetness a fully fermented cider cannot.
The organisms involved
Where in the process it arises
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.
Pasteurisation
Heating cider enough to inactivate the organisms that would spoil it, either in the sealed package or in-line before filling, at a measurable cost in fresh aroma.
Faults it is confused with
These present similarly. What separates them is set out on each page.
Unwanted refermentation
Fermentation restarting in a sealed container, generating carbon dioxide that was not planned for and pressure that a bottle may not withstand.
Hydrogen sulphide
A rotten-egg or drain smell from hydrogen sulphide produced by stressed yeast, usually the first visible consequence of a nitrogen-short juice.
Microbial haze
Cloudiness caused by a growing population of spoilage organisms, and therefore a symptom of something worse rather than a clarity problem in itself.
Acetaldehyde excess
A bruised-apple, green-nut or sherry aroma from acetaldehyde, produced by oxidation, by film yeast, or left behind by a ferment that was interrupted.
Where this comes up in a guide
The link lands on the step where the fault arises rather than at the top of the pathway, because that is where the decision that causes it is taken.
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.
- How do i get rid of the sulphur smell in my cider — Racking with a little splashing usually blows off free hydrogen sulphide while it is still fresh. Once it has reacted into mercaptans the smell becomes rubbery and no longer responds to aeration.
- Why did my sweetened cider start fermenting again — Live yeast met the sugar that was added back. Sweetening is only stable if the yeast has been removed by sterile filtration, killed by pasteurisation, or held in check by sorbate together with sufficient sulphite.
- How many calories are in cider — Roughly 40 to 60 kcal per 100 ml for most ciders, so a UK pint falls somewhere around 200 to 250 kcal. Alcohol contributes about 7 kcal per gram and residual sugar about 4, so both strength and sweetness matter.
- How do i make my cider sweeter
- Which sugar is most of the sugar in apple juice — Fructose, by a long way. Apple juice carries roughly twice as much fructose as glucose, with a smaller amount of sucrose, and fructose is the sweetest of the three on the tongue.
- Why is sorbitol important in perry — Sorbitol is a sugar alcohol that pears carry in quantity and that Saccharomyces cannot ferment. It passes through the whole fermentation untouched, so a perry can taste sweet while being dry by measurement.
Where to go next
- The fault finder — Describe what you can smell and see, and narrow it down from the signs.
- All faults — Grouped by where they come from and how serious they are.
- Cider science — The chemistry and microbiology these faults come out of.
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.
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.
Research on pear juice composition and sorbitol in perry
Various journals and institute reports · peer-reviewed literature · registered as competent for this subject
The evidence base for the single most important chemical difference between cider and perry: pears carry substantial sorbitol, which yeast does not ferment, so a fully fermented perry retains sweetness a fully fermented cider cannot.