Storage
Cold chain
Keeping an unpasteurised, unfiltered or back-sweetened cider refrigerated from the packaging hall to the point of sale, because refrigeration is the only thing holding it stable.
Also called chilled distribution, temperature-controlled distribution.
- Stage
- Storage
- Traditional in
- No single tradition — used wherever it suits
- What it most changes
- Sweetness and Carbonation
- Safety
- Carries a safety consideration — see below
A chilled, unstabilised cider that is allowed to warm can referment inside a sealed bottle or can, and the pressure that develops has no upper limit set by the package. Treat any warmed pack of an unpasteurised sweetened cider as potentially over-pressurised: chill it thoroughly before handling, keep it away from the face when opening, and open it slowly. Where a chain break is known to have occurred across a delivery, assess the whole consignment rather than a single container.
What it is
A cold chain is an unbroken sequence of refrigerated handling — cold store, chilled vehicle, chilled warehouse, chilled retail display — applied to a product that is not stable at ambient temperature. In cider it is required wherever the package contains both fermentable sugar and viable organisms: back-sweetened ciders that have not been pasteurised or sterile-filtered, live unfiltered ciders, and anything sweetened with fruit or juice after fermentation. Refrigeration in these cases is not a matter of serving preference. It is the stabilisation method, and it works only for as long as it is maintained.
Why it is used
- It is the alternative to pasteurisation, sterile filtration or preservative addition for a producer who wants a live, unheated, unfiltered product with residual sweetness.
- It suppresses the growth and metabolic rate of yeasts and bacteria so that a package which is chemically capable of refermenting does not do so within its intended life.
- It slows every other degradative reaction at the same time, so the aroma of a fresh product survives distribution better than it would at ambient temperature.
How it works
- Microbial growth rate is strongly temperature dependent, so chilling does not sterilise a cider but reduces yeast and bacterial activity to a level at which measurable change does not occur within the product’s dated life.
- Where the chain breaks, surviving yeast resumes fermenting the residual sugar, producing carbon dioxide inside a sealed container and, in cans and bottles, raising pressure beyond what the package was filled to hold.
- Warming simultaneously reduces the solubility of carbon dioxide, so a chilled product that has warmed both contains more gas and holds less of it in solution — which is why a broken chain shows up as gushing on opening.
- Renewed microbial growth also produces visible haze and sediment, and where spoilage organisms rather than the original fermentation yeast take hold, it produces acetic, lactic or mousy off-characters as well.
- Some organisms are specifically adapted to this niche: sulphite- and preservative-tolerant species such as Zygosaccharomyces bailii and Saccharomycodes ludwigii survive treatments that eliminate ordinary yeast, and a warmed package gives them exactly the substrate they need.
What it changes
The direction this step pushes the finished drink in, dimension by dimension. A direction, not a measurement: how far it moves depends on the juice, the temperature and how the step is carried out.
| Dimension | Direction | Why |
|---|---|---|
| Sweetness | Preserves | Residual sugar survives only because the organisms capable of consuming it are held below the temperature at which they metabolise appreciably; the sweetness of an unpasteurised back-sweetened cider is a refrigerated equilibrium rather than a fixed property. |
| Carbonation | Preserves | Cold liquid holds dissolved carbon dioxide far more readily than warm, so an unbroken chain keeps the gas in solution where it was set at filling instead of allowing it to migrate to the headspace. |
The chemistry and the organisms
What is actually being changed, and by what. Each entry says what that compound or organism does in cider generally; this page is one place it does it.
Compounds involved
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.
Carbon dioxide
The other product of fermentation, which protects a cider from air while it is being made and, dissolved in the finished drink, changes both its texture and its perceived acidity.
Sucrose
The disaccharide of apple juice and the sugar most often added to it, split into glucose and fructose by the yeast’s own invertase before any of it is fermented.
Organisms involved
Saccharomyces cerevisiae
The yeast that finishes essentially every cider, whether it arrives in a sachet or from the fruit, the press and the vessel.
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.
Saccharomycodes ludwigii
A large, sulphite-resistant yeast that refements sweet cider in bottle and is one of the classic causes of unwanted secondary fermentation.
Film yeasts
A functional grouping rather than a taxon: the oxidative yeasts that form a skin on cider exposed to air and consume its alcohol and acid.
What it is done with
What can go wrong
Faults that begin at this step, or that this step makes more likely. Each one is set out with its causes and whether it can be put right.
Unwanted refermentation
Fermentation restarting in a sealed container, generating carbon dioxide that was not planned for and pressure that a bottle may not withstand.
Bottle over-carbonation
More dissolved carbon dioxide in the bottle than intended or than the glass is rated for — a presentation problem at the mild end and a physical hazard at the severe one.
Gushing
Cider that erupts from the bottle on opening, either because it is over-pressurised or because something in it is nucleating the dissolved gas violently.
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.
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.
Cooked character
A stewed-apple, caramel or jam-like character from heat applied to juice or cider, most often through pasteurisation or hot storage.
Light strike
A skunky, cooked-cabbage or drain-like aroma produced when light acting on riboflavin generates sulphur compounds in a bottle.
Styles it produces
Categories in which this step is characteristic or required. Some name it in their definition; for others it is simply how they have always been made.
Unfiltered cider
Cider packaged without filtration, retaining suspended yeast and fine solids and the body and aroma that come with them.
Fruit cider
Cider with other fruit added as juice, purée or flavouring, a category that now accounts for a large share of the global market and spans a very wide range of practice.
Sweet cider
Cider in which sugar is the leading sensation, whether retained from an arrested fermentation, added after it, or produced by keeving.
More on cold chain
The category of cider that needs a cold chain is precisely defined and larger than it looks. Any cider carrying fermentable sugar that has not been pasteurised, sterile-filtered or chemically stabilised falls into it, and that includes most craft back-sweetened product, ciders sweetened with juice or fruit after fermentation, and live unfiltered ciders sold in bottle or box. It also includes ciders whose producer believes fermentation to be complete but which retain a slow-fermenting sugar or a stress-tolerant organism. The chemistry does not care about the producer’s intention; if there is substrate and there are organisms, only temperature is standing between the package and a fermentation, and temperature is the variable a producer loses control of first.
The chain breaks in predictable places, and none of them is the producer’s own cold store. It breaks at the transfer between vehicle and depot, where pallets stand on a loading dock; in an ambient vehicle used because the chilled one was unavailable; in a back-of-store area where a delivery waits to be put out; and, most commonly of all, on a shelf, where a product designed for chilled display is merchandised warm because it looks like every other cider on the fixture. Export magnifies every one of these. A producer who cannot verify chilled handling all the way to the shelf should stabilise the product instead rather than assume the chain will hold.
What a break actually causes is worth stating in order. First, imperceptible microbial activity resumes. Then gas accumulates: bottles gush, cans firm up, boxes inflate. Then haze appears as the population grows, and sediment follows. Finally, if the organisms present are spoilage rather than fermentative, the sensory profile changes — acetic sharpness, lactic softening, or in the worst case the mousy character associated with certain lactic bacteria and Brettanomyces. None of this is reversible, and re-chilling a warmed pack halts the process without undoing it. The practical conclusion is that cold chain is a design decision made at packaging, not a logistics detail settled afterwards.
Related processes
Steps that sit alongside this one, replace it, or depend on it having been done.
Stabilisation
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.
Stabilisation
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.
Blending
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.
Storage
Shelf-life management
Establishing how long a cider stays acceptable in its package and setting a durability date that reflects evidence rather than convention.
Packaging
Bottle pressure management
Matching the pressure a carbonated cider will actually generate to glass that can contain it, taking account of temperature and of any fermentable sugar left in the bottle.
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 long does cider last — An unopened commercial cider is usually at its finest within a year of packaging, and filtered, pasteurised products carry a stated date. Strong, tannic, bottle-conditioned ciders can improve for several years.
- How do i make my cider sweeter
- How much pressure builds up in a bottle of cider — Enough to matter. Every gram of sugar fermented in a sealed bottle produces gas, and a bottle not rated for it can fail. The French cider appellations require a minimum of 1.0 to 1.5 bar at 20 °C, and a bottle-conditioned cider can go well beyond that if it was filled with more sugar than intended.
- Which yeast ferments cider — Saccharomyces cerevisiae finishes almost every cider fermentation, whether it was pitched or arrived from the press house. In a spontaneous ferment it is not the first organism present, only the one that survives the alcohol it makes.
- Why did my cider bottles explode — Because fermentable sugar was still present, or too much priming sugar was used, and the pressure exceeded what the bottle could hold. Never bottle a cider whose gravity is still falling, and never use bottles not designed for pressure.
- What is fruit cider — Fruit cider is cider flavoured with another fruit, either as juice, purée or flavouring, added after fermentation. How much apple has to remain varies by jurisdiction, and in some markets very little does.
Where to go next
- How cider is made — The whole sequence, stage by stage, with the choices open at each one.
- Cider science — The chemistry and microbiology the methods on this page rest on.
- Troubleshooting — What goes wrong, how to recognise it, and whether it can be reversed.
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.
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.