Storage
Storing a part-finished batch
How do I store cider that is part-way through — a partly full fermenter, or cider waiting to be bottled?
In short
The controlling problem is headspace. Cider in a partly full vessel is exposed to a volume of air, and that air enables oxidation, acetification and film yeast — the three ways a sound batch is lost between operations.
The remedies, in order of effectiveness, are to eliminate the headspace by topping up or moving to a smaller vessel, to displace the air with carbon dioxide, and to keep the vessel cold.
A batch that must be left part-full and unprotected is on a clock measured in days, not weeks.
What goes wrong in a headspace
Oxidation runs continuously wherever cider meets air, and a large surface in a wide vessel accelerates it. The damage is the same as in a bottle but far faster, because the quantity of oxygen available is much greater and it is constantly renewed if the vessel is not sealed.
Acetobacter needs oxygen, alcohol and warmth, and a part-full vessel supplies all three. It grows at the surface and at the liquid-air-vessel boundary, and it converts ethanol to acetic acid. Once a batch has begun to acetify there is no remedy: the acetic acid cannot be removed, and blending it away merely spoils more cider.
Film yeasts — Pichia, Candida and related organisms — grow as a pellicle on the surface of a standing cider, and they metabolise ethanol and organic acids directly. A batch under a film loses alcohol, acidity and character, and takes on a flat, dusty quality.
A fourth risk is simply that a partly full vessel is more thermally responsive and less stable than a full one, so it follows the temperature of the room more closely.
The remedies, in order
- Move the cider into a vessel it fills. A full container has essentially no headspace, and this is the most effective single action available.
- Top up with more of the same cider, or with a compatible cider from another batch. Traditional practice tops up during maturation for exactly this reason.
- Displace the headspace with carbon dioxide, which is denser than air and will sit on the surface of the cider if introduced gently. This works well in a sealed vessel and poorly in an open one.
- Fit an airlock or a bung. It does not remove the air already present, but it prevents fresh air being drawn in as the vessel breathes with temperature.
- Keep it cold. Both Acetobacter and film yeasts grow slowly at low temperature, and cold slows chemical oxidation as well.
- Consider sulphite where the batch and the style permit it; free sulphur dioxide binds oxidation products and suppresses spoilage organisms, and its effectiveness depends sharply on pH.
- Where none of these is possible, plan to finish the batch quickly rather than store it.
Common situations
| Situation | Chief risk | What to do |
|---|---|---|
| Fermenter part-emptied after racking | Oxidation and acetification in a large headspace | Rack into a vessel it fills; use a smaller demijohn for the remainder |
| Cider waiting to be bottled | Oxidation; surface film if it stands for weeks | Seal, keep cold, bottle sooner rather than later |
| Blending trial remainders | Small volumes, large relative surface | Consolidate into small full bottles; use them first |
| A vessel emptied to half by drawing off | Continuous air exchange at the tap and the lid | Transfer down into smaller containers rather than leaving it |
| Cider left over cold winter in an outbuilding | Freezing; thermal cycling drawing air in | Full vessels, sealed, somewhere that does not freeze |
Recognising a batch that has gone
The nose gives the answer before anything else. A sharp acetic smell above the vessel, particularly one that is stronger at the surface than in a drawn sample, means acetification has started at the interface. A visible film — white, grey or wrinkled — is a film yeast pellicle.
A browning colour and a flattening of the aroma, without either of the above, is oxidation. Depending on how far it has gone, the batch may still be usable, particularly if it is going into a blend with fresher cider or if the style tolerates oxidative character.
Where a batch has genuinely turned acetic, the only constructive use is as vinegar, and that is a deliberate process rather than a salvage operation. It is worth saying plainly that there is no treatment that removes acetic acid from cider.
Also answered on this page
Questions this page covers, so you can tell at a glance whether it is the one you want.
- Can you leave cider in a half-empty fermenter?
- How do I stop my cider turning to vinegar?
- What is the white film on my cider?
Related
Topic
How long an opened bottle keeps
The same problem at the scale of one bottle.
Production
Topping up
The traditional answer to a headspace during maturation.
Fault
Acetification
The most decisive way a part-finished batch is lost.
Fault
Film yeast growth
The surface pellicle and the organisms that form it.
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.
- 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 long does cider last once the bottle is opened
- How much headspace should a cider fermenter have
- What is the white film on top of my cider — A dull white or grey skin is film yeast growing on the surface where the cider meets air. It is not mould, and it is a warning that the vessel is not full or not sealed.
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.
The New Cider Maker’s Handbook: A Comprehensive Guide for Craft Producers
Claude Jolicoeur, Chelsea Green Publishing, 2013. ISBN 9781603584739 · reference work · bibliographic record verified, not opened 2026-08-25
Bibliographic record verified on 2026-08-25 against the Open Library union catalogue: Chelsea Green Publishing, 2013, ISBN 9781603584739, one edition recorded. That establishes the citation points at a real book in a stated edition, which is what a citation needs and is all it establishes. No copy was opened and nothing is quoted from it. The book itself is in print and not digitised in any open collection; where CiderHQ needs a figure from this territory it uses an accessible research source instead and says so.
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.
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.
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.