Packaging
Kegging
Filling cider into a sealed keg for gas dispense or into a vented cask for gravity and handpump service — two formats whose difference is not the container but whether the cider ever meets air.
Also called keg filling, cask racking.
- Stage
- Packaging
- Traditional in
- Somerset, Herefordshire, Gloucestershire
- What it most changes
- Carbonation and Oxidative character
- Safety
- None recorded
What it is
Kegging in the broad sense covers filling cider into any bulk dispense container, but it hides a real division. A keg proper is a sealed stainless vessel from which cider is pushed by applied carbon dioxide or a gas mix, never contacting air, and which can stand connected for a long period. A cask, in the traditional English sense, is vented to atmosphere once broached and served by gravity tap or beer engine, with air replacing every pint drawn. The cider inside is usually different too: keg product is generally filtered, stabilised and carbonated, cask product often none of those.
Why it is used
- It removes the cost, weight and waste of individual containers for cider sold by the glass, which is why the on-trade runs on it almost everywhere.
- A sealed keg protects the product completely between filling and dispense and holds an applied carbonation level indefinitely, so a bar can serve consistent cider over weeks.
- The vented cask is what makes traditional draught cider possible at all: unfiltered, unpasteurised, uncarbonated cider cannot be served through a pressurised system without being changed into something else.
How it works
- A sealed keg is filled through a single spear valve after being cleaned and purged, so the cider displaces inert gas rather than air, and the same spear later admits dispense gas above the liquid and carries the liquid out from the bottom.
- Applied gas pressure has to be matched to the cider’s existing carbonation and to the cellar temperature: too little and gas comes out of solution over days, too much and it is driven in, so a keg on the wrong pressure changes the product it was meant to preserve.
- A vented cask works on the opposite principle. Once the shive or keystone is opened, air enters as cider leaves, and the cider is in continuous contact with oxygen and with whatever airborne organisms the cellar carries.
- That air contact starts a clock: acetic acid bacteria oxidise ethanol to acetic acid, and film-forming yeasts colonise the exposed surface, so a broached cask has a service life measured in days rather than weeks and cannot be resealed back to its former state.
- Line and coupler hygiene is part of the process rather than an adjunct to it, because the dispense line between container and tap holds residual liquid at ambient temperature and is the most reliable place in any bar to grow a spoilage population.
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 |
|---|---|---|
| Carbonation | Either way | A sealed keg holds whatever gas level the applied pressure and cellar temperature sustain, whereas a vented cask has no gas applied at all and settles towards the still or barely petillant condition that traditional draught cider is defined by. |
| Oxidative character | Either way | The keg excludes air entirely and holds oxidative development where it was at filling; the broached cask admits air continuously, so oxidative and eventually acetic character build from the moment it is opened. |
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
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.
Dissolved oxygen
Essential to a healthy yeast population at the start of fermentation and the principal enemy of a cider from the moment fermentation ends.
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.
Organisms involved
Acetobacter aceti
An acetic acid bacterium that oxidises ethanol to acetic acid wherever cider meets air, and the organism behind most volatile acidity in cider.
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.
Where it is traditional
The places this step belongs to as a matter of practice. It is not a claim of exclusivity — a method can be traditional in one region and perfectly ordinary in another.
What it is done with
Kegs, couplers and dispense
A keg is a stainless or composite pressure vessel with a valve and a dip tube; gas pushes the cider up and out, and the coupler is what connects the dispense line to a particular design of valve.
Counter-pressure filling
Carbon dioxide stays dissolved only under pressure, so carbonated cider poured into an open bottle foams, loses its gas and takes on air; a counter-pressure filler removes the pressure difference by purging and pressurising the bottle first, and vents it under control at the end.
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.
Acetification
The active conversion of a cider’s ethanol into acetic acid by acetic acid bacteria at an air interface — the process, running in the vessel, that produces volatile acidity.
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.
Oxidation
The cumulative effect of oxygen on finished cider: fruit aroma flattens, colour deepens towards amber, and a bruised-apple or sherry-like character replaces the fresh one.
Flat and lifeless
A cider with nothing obviously wrong and nothing to say: aroma faded, acidity dulled, finish short — usually the cumulative result of over-processing or slow oxidation.
Plastic and packaging taint
Plastic, rubber, adhesive or chemical notes picked up from unsuitable containers, liners, hoses, gaskets or cleaning residues.
Metallic taint
A metallic, inky or blood-like taste from dissolved iron, copper or zinc picked up from equipment, usually accompanied by accelerated oxidation.
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.
Traditional draught cider
Cider dispensed from cask, bag-in-box or gravity without added gas, in the form that British cider has historically been drunk in pubs and at the farm gate.
Modern mainstream cider
The industrially produced, consistent, carbonated cider that accounts for most of what is sold worldwide, generally made partly from concentrate and finished to a fixed specification.
Australian cider
Cider from Australia, dominated by a large mainstream sector using dessert fruit and concentrate, with a smaller full-juice movement working from cool-climate orchards.
Irish cider
Cider from Ireland, dominated commercially by large-scale production from Armagh and imported fruit, with a smaller full-juice sector working from orchard-grown apples.
More on kegging
The definitional point matters because it is a consumer-facing one. The British real cider definition, as maintained by the campaigning body that promotes it, turns on what has been done to the cider rather than on the container: full juice, not carbonated with added gas, not pasteurised, and not dispensed under applied pressure. A cider meeting that description is served by gravity from a cask on stillage or drawn by hand pump, and it is a live product that continues to change in the cellar. A cider that has been filtered, pasteurised, force-carbonated and put into a sealed keg is a different proposition, whatever the same producer’s name on the font might suggest. Both are legitimate; conflating them is what the definition exists to prevent.
For the producer, the two routes impose different disciplines. Keg product has to be genuinely stable before it is filled, because a keg is a sealed pressure vessel and residual fermentable sugar with live yeast will raise pressure inside it unpredictably; it also has to be carbonated to a level the trade can dispense, which means agreeing gas pressure and cellar temperature with the outlet rather than assuming them. Cask product has to be racked bright enough to serve but not so bright that it has nothing left, vented at the right moment, and — crucially — sold quickly. A producer supplying casks is effectively asking the publican to finish the product, and the cider’s reputation rests on cellar practice that the producer does not control.
What goes wrong is mostly a failure of the clock or of the line. A broached cask left connected past its window turns first thin and oxidised, then unmistakably acetic, and grows a film across the surface that the next pint carries into the glass. Kegs fail less dramatically but more insidiously: gas set too high over-carbonates the cider in place, gas set too low lets it go flat, and a dispense line that is not cleaned to schedule sours everything passing through it regardless of how sound the container is. In practice the majority of complaints about draught cider quality trace to the cellar and the line rather than to the cider that left the producer.
Related processes
Steps that sit alongside this one, replace it, or depend on it having been done.
Carbonation
Forced carbonation
Dissolving carbon dioxide into cider under pressure to a chosen level, giving complete control of the sparkle and none of the flavour a second fermentation would contribute.
Packaging
Bag-in-box
A collapsing laminate bladder in a card outer, the standard farmgate and draught format, which keeps air out during dispense but lets oxygen through the film over weeks.
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.
Juice treatment
Sanitation
The cleaning and sanitising discipline that underlies every other process, and why removing soil must come before any attempt to kill organisms.
Stabilisation
Filtration
Passing cider through a porous medium to reach a stated visual brightness, at a real cost in colloidal material, body and aroma.
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 need to be refrigerated — Unopened, no — cool and dark is enough for most cider. Unpasteurised, unfiltered cider keeps far better cold, and anything opened should go in the fridge.
- 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.
- How is cider carbonated — Either by dissolving carbon dioxide into finished cider under pressure, or by letting a small second fermentation produce the gas inside a sealed bottle or tank. The first is faster and more repeatable; the second leaves sediment and a finer bead.
- Why does my cider taste like vinegar — Acetic acid bacteria have reached the cider and, given air, are converting its alcohol into acetic acid. The cause is almost always oxygen — an unfilled vessel, a leaking bung, or a slow transfer.
- How much acetic acid is normal in cider — A small amount is present in every cider and contributes lift. Sound Asturian sidra natural has been measured at 0.2 to 0.3 g/L, and a clean modern cider much above about 0.7 g/L is generally showing a fault rather than a style.
- What is oxidation in cider
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.
CAMRA cider and perry standards
Campaign for Real Ale · specialist organisation · retrieved 2026-08-24
Opened on 2026-08-24. Registered for the consumer-campaigning vocabulary — "real cider", "full juice" — which is advocacy language rather than legal definition, and is recorded as such wherever CiderHQ uses it.
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.