Equipment
The apple washer and the flotation tank
Why do cider apples need washing, and how is it done?
In short
Most cider fruit is shaken down or allowed to fall and then swept or harvested off the ground, which is why it reaches the mill carrying soil, grass, leaf, twig, small stones and whatever has begun to rot on it. Dessert fruit is picked from the tree; cider fruit generally is not.
The usual arrangement is water. Apples float and stones and soil sink, so a flotation tank or a wash flume separates the two without any moving part, and the fruit leaves on an elevator through a spray rinse, sometimes over brushes or rollers.
Washing is not about appearance. Soil carries both the grit that wears a mill and the organisms that compete with the yeast, and the wash is also the last point at which a rotten apple can be seen and taken out before it disappears into the pomace.
Why the fruit arrives dirty
The harvesting methods that suit cider fruit all put it on the ground. Fruit is shaken from the tree onto grass and swept up, or it is left to drop and collected over several passes, or a mechanical harvester sweeps it into windrows and lifts it. In a wet autumn the orchard floor is mud, and in a grazed orchard it is worse than mud. None of this is a failure of care; it is the economics of a crop that is going to be crushed rather than sold whole.
What comes with the fruit is therefore soil, wet grass, leaf, fallen twig, and stones — including stones from a gravel headland, from a track, or from whatever was used to fill a rut years ago. Metal arrives too: fencing wire, a bolt, a fragment of a machine. A hammer mill is designed to survive that and a scratter is not, but neither is improved by it.
The other passenger is rot. Fruit that has lain on wet ground bruises and is colonised, and the moulds that follow — Penicillium expansum above all — are the reason patulin is a regulated contaminant in apple products. A wash stage that is coupled to a sorting table is the point at which that fruit is caught, and it is far more valuable for that reason than for anything the water does.
The flotation tank and the flume
An apple floats because a substantial fraction of its volume is intercellular air; soil, clods and stones do not. Dropping fruit into a tank of water therefore sorts it for nothing: the fruit rises and is carried off the surface by a paddle, a chain or a rising elevator, while the heavy material settles into a sump that is periodically drawn off. Machines built specifically for this are sold as destoners, and a plain tank with an elevator out of it does most of the same work.
A flume extends the idea. Fruit is floated along an open channel of moving water from the tip point to the mill, so the water transports as well as washes, and it does so with almost no bruising because the fruit is never dropped onto anything hard. Flumes take up length rather than height, which is why they suit a plant laid out on one floor and not a converted barn.
Water is the constraint. A flume or flotation tank uses a great deal of it, so it is recirculated, and recirculated water accumulates soil, sugar and an enthusiastic microbial population over a day of running. Plants therefore filter, settle and treat the circulating water and change it on a schedule, and the treatment used, its concentration and its permitted residue are matters for the chemical supplier and for local food and water regulation rather than something to be improvised.
The rule that follows is the one that matters most: the final rinse is always on fresh water. Fruit that has been floated in recirculated water and then rinsed with clean water has been washed. Fruit that has only been floated has been moved.
What each stage actually achieves
Read down that last column and the point of the whole line becomes clear. Water handles soil and stones and does it cheaply; it does nothing at all about rot, and no amount of washing makes a mouldy apple acceptable. The sorting stage is the food safety control, and the wash exists partly to make the sorting possible by getting the mud off so that people can see what they are looking at.
| Stage | What it removes | What it leaves |
|---|---|---|
| Dry pre-clean — grading rollers, a fan or a debris chain | Loose leaf, grass, twig and light trash | Everything adhering to the fruit |
| Flotation tank or destoner | Stones, clods, soil that has settled, heavy debris | Adhering mud, mould, anything that floats |
| Flume transport | Loosens adhering soil while conveying | Firmly attached soil and all rot |
| Brush or roller bed | Adhering soil and surface deposit; scuffs waxy fruit | Rot, internal damage, anything inside the fruit |
| Fresh-water spray rinse | Wash-water carryover and the last loosened soil | Everything the earlier stages left |
| Sorting table or belt with people on it | Rotten, mouldy and heavily damaged fruit; foreign objects | Whatever is not visible from the top surface |
Washing does not remove rot
At small scale
- A tub of clean water and a hand is a flotation tank. Tipping a bucket of windfalls into it brings the stones and soil to the bottom in seconds and is worth doing every time.
- Rinse in fresh water afterwards, not in the tub the fruit was floated in.
- Sort on a table or a clean tarpaulin, in daylight, before milling and not during it; once fruit is in the hopper nobody is looking at it.
- Cut a suspect apple open. Brown flesh well beyond the visible bruise is the sign to reject the fruit rather than trim it.
- A wet, sugary wash area is a vinegar fly nursery. It is hosed down and dried at the end of every day, not at the end of the week.
Also answered on this page
Questions this page covers, so you can tell at a glance whether it is the one you want.
- Do I need to wash apples before making cider?
- How does a flotation tank work?
- Can washing remove rot from apples?
Related
Production
Fruit washing
Production
Fruit sorting
Production
Windfall management
Production
Shaking and collecting
Production
Patulin control
Production
Milling
Chemistry
Patulin
Microbiology
Penicillium expansum
Fault
Patulin contamination
Fault
Mould taint
Topic
Elevators, conveyors and hoppers
Topic
Bulk bins, crates and pallets
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 milled for cider
- How do cider makers keep patulin out — By sorting rotten fruit out before milling, because patulin comes from moulds growing on damaged apples. Fermentation reduces what gets through, so fermented cider carries no limit where juice does.
- Can you use windfall apples for cider — Traditional cider making relies on fruit gathered from the ground, and there is nothing wrong with it if it is sound. Rotten fruit is a different matter: brown rot carries patulin into the juice and should be discarded, not pressed.
- Does cider contain patulin — Patulin comes from mouldy fruit and is regulated in apple juice. Fermentation reduces it substantially, so fermented cider carries far less risk than unfermented juice made from the same fruit.
- Why does mouldy fruit matter for cider — Penicillium expansum is the blue mould of stored apples and the principal producer of patulin. Sorting rotten fruit out before milling is a food-safety step and not only a quality one.
- Are apples washed before making cider
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.
Hochschule Geisenheim University — beverage technology
Hochschule Geisenheim · university · retrieved 2026-08-24
German beverage-technology research covering apple wine and fruit juice processing, including the enzymology of clarification.
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.