Organism
Candida species
A large, historically artificial grouping of yeasts that appears throughout cider microbiology, containing organisms with little in common beyond the absence of a sexual stage.
- Kind
- Yeast
- Binomial
- Candida spp.
- Role
- Primary fermentation, Surface film, Spoilage, Present throughout
What it does
- Contributes to the early non-Saccharomyces phase of a spontaneous ferment, with various species fermenting weakly, consuming oxygen and producing esters before ethanol excludes them.
- Includes strongly fructophilic species, which matters in apple juice because fructose is the dominant sugar and is what remains when a ferment stalls.
- Includes film-forming, oxidative species that behave like Pichia — growing at the surface of ullaged cider and oxidising ethanol rather than fermenting sugar.
- Produces acetate esters and, in some species, appreciable acetic acid, so its overall effect on volatile acidity depends entirely on which species is present.
Conditions it works in
What the organism tolerates and what suppresses it. These are the levers a maker actually has: temperature, acidity, air, alcohol and sulphite.
| Condition | What is recorded |
|---|---|
| Temperature | Broadly 5–35 °C across the group; no single figure is meaningful for a grouping this heterogeneous. |
| pH | Members are found across the whole fruit-juice and cider range, roughly pH 3.0–4.5. |
| Oxygen | Both fermentative and oxidative members are present in the group, which is part of why it is not a useful functional category. |
| Alcohol tolerance | Generally low, mostly below 6% ABV, with exceptions. |
| Sulphite tolerance | Variable and species-dependent; most members are suppressed by normal juice sulphiting. |
What it produces
Compounds this organism makes. Which organism made a compound usually decides whether it reads as a feature or as a symptom.
Ethyl acetate
The most abundant ester in cider, giving lift and pear-drop at low concentration and nail varnish at high, and the earliest audible warning that acetic bacteria are at work.
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.
Acetic acid
The vinegar acid, made by bacteria oxidising ethanol whenever air reaches a cider, and the one fault in cider that no later processing can undo.
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.
Glycerol
A syrupy three-carbon alcohol yeast produces as a side reaction of fermentation, which adds weight to a dry cider and is the raw material for one of its more obscure faults.
Faults it causes
Faults this organism is implicated in. Several are faults only against a particular expectation — the same activity is a signature elsewhere.
Film yeast growth
A pale, powdery or wrinkled film of aerobic yeast growing on the surface of a standing cider, consuming alcohol and acid and producing acetaldehyde.
Volatile acidity
The measurable fraction of acidity that can be steam-distilled off, dominated by acetic acid and read as vinegar sharpness in the nose and a hard, hot finish.
Ethyl acetate taint
A solvent, nail-varnish or pear-drop aroma from ethyl acetate, the most abundant ester in cider and the one that turns from lift to fault over a narrow range.
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.
Vinegar fly contamination
Small flies carrying acetic acid bacteria and spoilage yeasts directly into juice and cider, and depositing them wherever they land.
Yeast haze
Cloudiness from yeast cells that have not settled out, usually because the strain flocculates poorly or the cider has not been left alone long enough.
Where in the process it appears
Wild fermentation
Letting the microflora already present on the fruit and in the press house carry the ferment, in a succession rather than as a single organism.
Microbial succession
The ordered handover of a spontaneous ferment from apiculate yeasts to *Saccharomyces* to lactic acid bacteria, and the spoilage organisms waiting at the end of it.
Sulphiting
Adding sulphur dioxide to juice to suppress spoilage organisms and oxidative browning, at a level that only means anything once the juice pH is known.
Sanitation
The cleaning and sanitising discipline that underlies every other process, and why removing soil must come before any attempt to kill organisms.
Topping up
Refilling a maturing vessel as evaporation and racking losses lower the level, so that no significant surface of cider is ever left in contact with air.
About Candida species
Candida is not a natural group. It was assembled as a place to put yeasts that reproduce only asexually — anamorphic yeasts with no known sexual stage — and organisms landed in it because of what had not been observed about them rather than because of what they are. The result is a genus that is polyphyletic in the strict sense: its members are scattered across the yeast phylogeny and are frequently more closely related to yeasts in other genera than to each other.
Molecular taxonomy has been dismantling it for two decades. Species have moved out steadily as their affinities became clear — Candida pulcherrima to Metschnikowia, Candida colliculosa to Torulaspora, Candida stellata and its relatives to Starmerella, Candida pelliculosa to Wickerhamomyces. Cider papers written twenty years apart can therefore describe the same organism under two names, and a reader comparing them without knowing that will conclude the population changed when only the nomenclature did.
CiderHQ keeps this record because the name is unavoidable in the literature, not because the grouping is informative. What can honestly be said is that yeasts reported as Candida are common in freshly pressed apple juice and in the early phase of spontaneous cider ferments; that some are fermentative and some oxidative film formers; and that any statement stronger than that has to name a species, and preferably a current one.
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 does cider ferment — Yeast consumes the sugar in apple juice and produces roughly equal masses of ethanol and carbon dioxide, along with the esters and higher alcohols that give cider much of its aroma. In a wild ferment several yeast species take turns before *Saccharomyces* finishes the job.
- Can you fix a cider that has gone vinegary — Not really. Volatile acidity cannot be removed at small scale, and blending it away only dilutes it. The realistic options are to accept it, to blend a lightly affected batch into a much larger sound one, or to let it finish becoming vinegar.
- How do i sterilise cider bottles — Wash them clean first, then sanitise with a no-rinse sanitiser or a sulphite solution, and fill while still wet with it. Bottles that look clean but have dried deposits inside are the usual source of bottle spoilage.
- Why does my cider smell like nail varnish — That is ethyl acetate, formed when acetic acid combines with ethanol. In small amounts it reads as pear drops; above threshold it smells of solvent or nail varnish remover and usually accompanies rising volatile acidity.
- Why is sulphite added to cider — Sulphur dioxide suppresses spoilage bacteria and wild yeast before fermentation and protects the finished cider from oxidation. How much of it is active depends strongly on pH, which is why low-acid juice is harder to protect.
- 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.
Where to go next
- All organisms — Grouped by what each does in the ferment, and by what kind of organism it is.
- Compounds — The chemistry this microbiology produces.
- Troubleshooting — Work from the symptom in the glass back to the organism.
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.