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Serving

Serving from a barrel or bag-in-box

How do you serve still cider from a barrel or a bag-in-box, and how long does it stay good?

In short

The governing difference is oxygen. A bag-in-box collapses as it empties, so the cider is never exposed to air and keeps for weeks after tapping; a rigid barrel or polypin admits air to replace what is drawn off, and the cider inside starts oxidising and acetifying from the moment it is broached.

Both are usually served without any applied gas pressure, by gravity, which is why the container has to be positioned, settled and vented properly before the first glass.

A tapped rigid container of still cider is generally best regarded as having days rather than weeks, and a warm room shortens that considerably.

Bag-in-box and rigid containers are not the same object

A bag-in-box holds the cider in a collapsible laminated pouch inside a cardboard outer, with a tap fitted to the pouch. As cider is drawn, the pouch collapses; no air enters, and the surface of the cider never meets a headspace. That is why an opened box of still cider keeps for weeks rather than days, and why bag-in-box became the standard format for farm-gate and small-producer still cider.

A rigid container — a wooden cask, a plastic polypin with a rigid wall, a stainless keg served by gravity, a bulk plastic drum — has a fixed internal volume. Cider leaves through the tap, and something must replace it. In gravity dispense that something is air, admitted through a vent. From that moment the cider has a headspace, and the headspace has oxygen in it.

Oxygen does two things to a still cider. Chemically it browns it and pushes the aroma towards bruised apple, sherry and eventually cardboard. Microbiologically it enables Acetobacter, which converts ethanol to acetic acid and turns cider into vinegar, and it enables film yeasts, which form a pellicle on the surface and strip the cider of character. Neither process is fast at cellar temperature, and both are much faster warm.

Setting up a gravity container

How long a tapped container lasts

Working expectations after broaching, still cider, no applied gas
ContainerAir contactWorking life once openedLimiting process
Bag-in-box, pouch collapses as it emptiesNoneSeveral weeks cool; less in a warm roomSlow oxygen ingress through the laminate and the tap
Polypin (semi-rigid, partially collapses)PartialOne to two weeks coolOxidation and acetification
Rigid plastic or stainless container, ventedFullTwo to five days coolAcetification and film yeast
Wooden cask, ventedFull, plus wood porosityTwo to four days coolAcetification, film yeast, and any resident organisms in the wood
Keg under applied carbon dioxideNone while gas remainsWeeks to monthsNot oxygen; eventually microbial or flavour change
These are working expectations, not guaranteesThe figures above assume a cool cellar and a container that is being drawn down steadily. A container that is opened, part-used and left standing warm for a week will deteriorate much faster than the table suggests. The reliable test is the cider itself: a sharpening acetic edge on the nose is the signal that acetification has started.

Serving temperature and the container

A large container has a great deal of thermal mass and changes temperature slowly. That is an advantage — the cider does not warm during a session — and a disadvantage, because a container that has been standing in a warm room for two days cannot be brought down to serving temperature quickly.

Traditional gravity cider is served at cellar temperature, which is broadly the 10–13 °C the still tannic styles want anyway. Where a bag-in-box needs to be colder, the practical approach is to take the pouch out of the box and refrigerate it, or to draw into a jug that is itself chilled.

Cider drawn by gravity is still and stays still. There is no carbonation to preserve, so pouring technique matters much less than it does with a bottle: the constraints are simply not disturbing the sediment behind the tap and not leaving the tap open where it can drip and attract vinegar flies.

Hygiene at the tap

The tap is the point where a container meets the outside world, and it is the commonest route by which spoilage organisms get in. Acetobacter is carried readily by vinegar flies, which are attracted to cider and can reach a tap that has been left wet.

Wiping the tap clean and dry after use, keeping any nozzle covered, and not leaving a jug or glass in contact with the tap outlet are the whole of the discipline. A tap that has developed a sticky film should be removed and cleaned rather than wiped.

A container that has begun to acetify cannot be recovered. Acetic acid does not go away, and there is no treatment at the point of service. The value of the hygiene is entirely preventive.

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