Equipment

Choosing a fermentation vessel: material and shape

What vessel should I ferment cider in, and does the shape matter?

In short

The material question comes down to three properties: how much oxygen crosses the wall, whether the vessel adds or absorbs flavour, and whether the surface can genuinely be cleaned and sanitised.

The shape question is less discussed and matters more than people expect. Surface-to-volume ratio governs how fast a ferment tracks room temperature; depth governs how compact the lees are and how much hydrostatic pressure the yeast works under; and the area of the liquid surface governs how quickly a surface film can establish.

For most makers the honest answer is that any inert, cleanable, sealable vessel of roughly the right size will make good cider, and that vessel choice matters far less than keeping it full and clean.

Materials compared

Two rows in that table deserve emphasis. Plastic is the vessel most small makers actually use and is entirely legitimate, provided it is genuinely food-grade and retired when it is scratched. Wood is the vessel most romanticised and is the hardest to keep sound; a maker who is not prepared to keep a cask full, cool and monitored will get vinegar rather than character.

Fermentation vessel materials against the properties that matter
Material	Oxygen ingress	Flavour contribution	Cleanability	Relative cost per litre	Best suited to
Glass	Effectively none	None	Excellent, but access is poor	High at small volume, impractical above about 25 L	Small batches and long maturation
Stainless steel	None through the wall; only at fittings	None	Excellent, and can be cleaned in place	High capital, very long life	Anything from a few tens of litres upwards
Food-grade HDPE or polypropylene	Low but not zero; scales with time and thinness	None when new; absorbs and re-releases taint over time	Good when new, poor once scratched	Low	Primary fermentation and short holding
Oak or chestnut cask	Low, mostly at head and bung; high per litre in small casks	Oak character, and any previous fill	Poor — porous, cannot be sanitised	Moderate second-hand, high new	Maturation where wood character is wanted
Large wooden vat or tun	Low per litre	Slight in an old vat; carries resident microflora	Poor	Effectively a fixture	Traditional wild-fermented production
Lined concrete	Very low through an intact lining	None	Good if the lining is sound, very poor if not	Low material cost, immovable	Large-volume fermentation with thermal stability

What shape does to a ferment

Surface-to-volume ratio governs heat exchange. A demijohn in a kitchen is essentially at room temperature, because it loses heat as fast as the ferment makes it. A cubic metre of fermenting juice is not: it generates heat faster than it can shed it and will run several degrees above ambient, sometimes far more. This is why temperature control is optional at five litres and essential at five thousand, and why the same yeast and the same juice give different results at different scales.

Depth governs the lees. A tall, narrow vessel produces a deep, compact lees bed with a small footprint; a wide, shallow one produces a thin lees spread over a large area. Deep beds compact and can become anaerobic and reductive, which is one route to sulphide character; thin beds are easier to rack off cleanly but expose more cider to whatever is happening at the surface.

At large scale, depth also imposes hydrostatic pressure. Carbon dioxide is more soluble under pressure, so the bottom of a tall tank holds more dissolved gas than the top, and dissolved carbon dioxide inhibits yeast. Very tall vessels can therefore ferment more slowly at the base, and commercial practice sometimes limits tank height for this reason rather than for any structural one.

The liquid surface area is the third variable. Film yeasts and acetic bacteria colonise a surface, and a wide surface gives them more to work with and more oxygen contact per litre. A narrow-necked vessel is not just easier to seal; it presents a smaller target.

Matching vessel to stage

Many experienced makers do not use one vessel throughout. Primary fermentation, which is vigorous, messy, self-protecting and short, suits a cheap wide-mouthed vessel that can be cleaned easily. Maturation, which is long, quiet and vulnerable, suits an inert impermeable vessel that can be filled to the top.

That approach also solves the volume problem. Racking loses volume, so the vessel that was correctly sized for the ferment is oversized for what comes out of it. Having a smaller vessel ready for the racked cider is a more reliable answer than topping up, and much more reliable than hoping the headspace does not matter.

The last consideration is one nobody enjoys: whether the vessel can be lifted, moved, emptied and washed by the people who will actually have to do it. A vessel that is too heavy to handle will be cleaned badly, and cleaned badly is the origin of most of the faults in this section.

Also answered on this page

Questions this page covers, so you can tell at a glance whether it is the one you want.

Does the shape of the fermenter matter?
What is the best cider fermenter?
Why does a big batch ferment hotter?

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.

Can i ferment cider in a plastic barrel, and how do i know it is safe — Plastic fermenters are usually high-density polyethylene, polypropylene or, for carboys, polyethylene terephthalate. All three are used throughout the food industry and none of them are a problem in themselves.
What should i know about stainless steel fermentation tanks — A stainless tank is a welded vessel, usually cylindrical, in an austenitic stainless grade chosen for corrosion resistance in acidic, chloride-containing conditions. It contributes nothing to the cider and lets no oxygen in.
What temperature should cider ferment at — Most cider is fermented cool, commonly between about 12 and 18 °C. Cooler ferments keep more fruit aroma and run slower; above the low twenties the cider tends towards hot, solvent-like higher alcohols.
Why does everyone say cleaning matters more than anything else — Cleaning removes soil — pomace, lees, tartrate, protein and the biofilm growing in it. Sanitising reduces the number of viable organisms on a surface that is already clean. They are two separate operations and the second does not work without the first.
How do i get rid of the sulphur smell in my cider — Racking with a little splashing usually blows off free hydrogen sulphide while it is still fresh. Once it has reacted into mercaptans the smell becomes rubbery and no longer responds to aeration.
What is racking in cider making — Racking is siphoning cider off the sediment it has thrown into a clean vessel, leaving the lees behind. It clarifies the cider and, in traditional practice, is also used to slow a ferment by removing yeast with the lees.

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 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.
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 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.

Where to go next

Cider making equipment — The rest of the equipment material, grouped by what each piece is for.
How cider is made — The methods this equipment exists to carry out.
Troubleshooting — The faults that are traced back to equipment and to cleaning.