Equipment
Hydraulic packs and rams
How does the hydraulics on a cider press work, and what can go wrong?
In short
A hydraulic pack is a self-contained unit: an oil reservoir, a pump driven by an electric motor or a hand lever, a directional control valve, a pressure relief valve, a gauge, and hoses running to one or more rams.
Because pressure in a fluid acts equally on every surface, a small pump piston working at high pressure moves a large ram piston with a force multiplied by the ratio of their areas. That is how a modest motor produces tens of tonnes at a press platen.
The great advantage over a screw is that the ram holds pressure by itself while the cake consolidates, so the press keeps working without anyone turning anything.
The parts and what each does
- Reservoir and oil: the working fluid, which must be the grade the manufacturer specifies and must be kept clean; contamination is the commonest cause of pump and valve failure.
- Pump: hand lever, air-driven, or electric. Two-stage pumps move the ram quickly at low load and then switch to a slow high-pressure stage once the cake resists.
- Directional valve: advances, holds or retracts the ram.
- Relief valve: sets the maximum pressure the system can reach. This is a safety device, not a convenience, and it is set to the press frame’s rating rather than the pump’s capability.
- Gauge: reads system pressure in bar or psi. Converting that to force at the platen requires the ram area, which is why press instructions give a maximum gauge reading rather than a maximum force.
- Hoses and couplings: rated assemblies with a finite service life. A hose is replaced on age and condition, not on whether it has failed yet.
Reading and using the gauge
The gauge is the only honest feedback a hydraulic press gives. Rising pressure with juice still flowing means the cake is still giving up liquid. Pressure holding steady with flow stopped means the cake has consolidated and further pressure will achieve nothing useful. Pressure falling on its own after the valve is closed means the cake is still creeping — which is normal, and is the moment to advance the ram again.
The technique that gets the yield is stepwise: raise to a moderate pressure, hold until flow slackens, raise again, and only approach the frame’s rated maximum at the end of the run. Going straight to maximum seals the surface of each layer and traps juice.
A press should never be run above the maximum gauge pressure marked on the frame, and a relief valve should never be adjusted to permit that. The frame, not the hydraulics, is what fails.
Oil and food
Hydraulic oil and juice occupy the same building, and hoses run over the press. A leaking hose or a weeping fitting above an open cheese contaminates the batch, and a hydraulic oil taint is not something that can be removed later. Presses intended for food use are normally arranged so that hoses and rams sit below or beside the product path rather than above it, and food-grade hydraulic fluids exist for applications where incidental contact is possible.
The pinhole leak deserves a particular warning. Hydraulic fluid escaping from a small hole at working pressure forms a jet that can penetrate skin and cause a serious injection injury that looks trivial at first. A suspected leak is found with a piece of card, never with a hand, and the system is depressurised first.
Stored energy and maintenance
Also answered on this page
Questions this page covers, so you can tell at a glance whether it is the one you want.
- What pressure should a cider press run at?
- Why does my press pressure drop on its own?
- Is hydraulic oil dangerous near juice?
Related
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 are apples pressed for cider — The fruit is first milled to a pulp, then that pulp is squeezed — traditionally in cloth-wrapped layers under a screw or hydraulic ram, and industrially in a belt or bladder press. Whole apples cannot be pressed usefully; they must be broken first.
- What is a rack and cloth press and why is the pomace built in layers — The pomace is spread on a square cloth laid in a shallow forming frame, the cloth corners are folded over to make a flat parcel, a slatted rack is laid on top, and the process repeats until a stack — the *cheese* — is built. The whole stack is then compressed, usually by a hydraulic ram.
- Which type of cider press should i use — No press is best. Each one sits at a different point on four trade-offs: how much juice it recovers, how much air the juice meets, how hard it works the solids, and how much labour and capital it needs.
- Is a basket press good enough for making cider
- What is a hydraulic cider press
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.
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.