Fruit preparation
Fruit washing
Removing soil, grass, stones and surface contamination from gathered fruit, usually in a water flume, before it reaches the mill.
Also called Washing, Flume washing, Fruit cleaning.
- Stage
- Fruit preparation
- Traditional in
- No single tradition — used wherever it suits
- What it most changes
- Not recorded as moving a sensory dimension
- Safety
- Carries a safety consideration — see below
Flume water is normally reused across many batches and becomes a cross-contamination route: soil, mould spores, yeast and acetic acid bacteria accumulate in it, and fruit washed late in a run can leave dirtier than it arrived. Change or filter the water on a defined schedule, keep the settling trap emptied, and finish with a rinse of potable water rather than recirculated flume water. Where a sanitiser is dosed into wash water, follow the supplier’s instructions for use and for handling — several are corrosive concentrates — and observe the residue requirements that apply to a food contact water in your jurisdiction.
What it is
The wet cleaning step between the fruit store and the mill. Fruit is tipped into a water channel or tank, floated along it, lifted out on an inclined elevator, and often brushed or sprayed on the way. The water does three jobs at once: it carries the fruit, it strips off adhering soil and grass, and it separates dense debris that sinks from fruit that floats. In small operations the equivalent is a dunk tank and a hose. Where the crop has been gathered from a sward or lifted by machine, washing is not optional — it is the only thing standing between the orchard floor and the mill.
Why it is used
- Ground-gathered and machine-harvested fruit arrives coated in soil, and soil carries grit that abrades mill and press surfaces as well as a heavy microbial load.
- Stones and clods travelling with the crop damage mill hammers and can cut a press cloth or a bladder, so removing them protects equipment as well as product.
- Orchards grazed by sheep, cattle, geese or poultry carry faecal contamination on the sward, and fruit that has lain in that sward carries it too.
- Wet fruit moves and separates more readily on an inspection belt than dry muddy fruit, so washing makes the sorting step that follows it materially more effective.
How it works
- Apples and pears are less dense than water and float, while stones, soil aggregates and metal sink, so a simple flume with a settling trap performs a density separation without any moving parts.
- Turbulence and the tumbling of fruit against fruit in the moving water dislodges adhering soil mechanically; brushes and spray bars finish what the flume starts.
- Washing removes surface material only — spores, soil and debris on the outside of the fruit. It does nothing to a fungus already established inside a lesion, and nothing at all to patulin already present in the flesh.
- Recirculated flume water accumulates the organic and microbial load stripped from every batch that has passed through it, so its capacity to clean falls as its capacity to contaminate rises.
The chemistry and the organisms
What is actually being changed, and by what. Each entry says what that compound or organism does in cider generally; this page is one place it does it.
Compounds involved
Organisms involved
Penicillium expansum
The blue mould of stored apples and the principal producer of patulin, the one genuine chemical safety issue that rotten cider fruit raises.
Botrytis cinerea
Grey mould: a broad-host-range fruit rot whose laccase enzyme oxidises phenolics and whose glucans make a juice difficult to clarify.
Acetobacter aceti
An acetic acid bacterium that oxidises ethanol to acetic acid wherever cider meets air, and the organism behind most volatile acidity in cider.
Gluconobacter oxydans
A sugar-preferring acetic acid bacterium abundant on damaged fruit and in fresh juice, which oxidises glucose to gluconic acid before fermentation begins.
What it is done with
The apple washer and the flotation tank
Cider fruit is gathered off the orchard floor, so it arrives with soil, grass, stones and rot attached; a flotation tank separates the fruit from the stones by density alone, and a spray or brush stage takes off what floating will not.
Elevators, conveyors and hoppers
Fruit moves by gravity where the building allows it and by flume, belt, bucket elevator or auger where it does not; each method bruises the fruit to a different degree, and each is a machine capable of drawing a person into it.
What can go wrong
Faults that begin at this step, or that this step makes more likely. Each one is set out with its causes and whether it can be put right.
Patulin contamination
Contamination of juice or cider with patulin, a mycotoxin produced by Penicillium expansum in rotting apples — a genuine food-safety question rather than a flavour one.
Mould taint
Musty, earthy, cellar-damp or rotten-fruit character carried in from mouldy fruit or from mouldy equipment, and a marker that the patulin question needs asking.
Volatile acidity
The measurable fraction of acidity that can be steam-distilled off, dominated by acetic acid and read as vinegar sharpness in the nose and a hard, hot finish.
Metal haze
A haze or dark cast caused by dissolved iron or copper picked up from equipment, forming insoluble complexes with phosphate or with the cider’s phenolics.
Metallic taint
A metallic, inky or blood-like taste from dissolved iron, copper or zinc picked up from equipment, usually accompanied by accelerated oxidation.
Smoke taint
Ashtray, burnt and medicinal character in cider made from fruit exposed to wildfire smoke, which enters the fruit as bound precursors and is released later.
More on fruit washing
How much washing matters depends almost entirely on how the fruit was harvested. A hand-picked crop that has never touched the ground needs little more than a rinse; a crop swept up from a grazed standard orchard after a wet week may arrive with as much soil as fruit, and no amount of downstream care compensates for putting that into a mill. The middle case, and the common one in traditional cider country, is fruit gathered from a mown sward in reasonable weather, where the flume is doing routine work rather than heroic work. Grazed orchards deserve specific attention: the practice of running sheep or geese under standard trees is old, ecologically sensible and still current in parts of the West Country and Normandy, and it puts faecal material on exactly the surface the crop will later lie on. Withdrawing stock before the drop begins is the orchard-side control; washing is the processing-side one.
The water itself is the part most often mismanaged. A flume holds a large volume that is expensive to heat, expensive to dispose of and tedious to change, so the pressure is always to run it longer than it should be run. As it ages it accumulates soil, sugar from split fruit, and a population of yeasts, acetic acid bacteria and mould spores that grows through the day; at that point the flume is inoculating the crop rather than cleaning it, and the fruit at the end of a long run can carry a heavier microbial load than the fruit at the start. Juice-technology guidance from institutions such as Geisenheim treats water management, settling-trap maintenance and a final clean-water rinse as integral to the wash rather than as refinements. Recovered wash water also has a disposal problem of its own, since it is high in organic load and cannot simply go to a watercourse.
What washing cannot do is worth stating plainly, because it is regularly over-credited. It removes what is on the outside of the fruit. A fruit whose flesh has been colonised by Penicillium expansum comes out of the flume just as contaminated as it went in, with the patulin still in the tissue and the rot still spreading, and if anything looks cleaner and is easier to miss on the belt afterwards. Washing is therefore a partner to sorting, not a substitute for it, and the sequence matters: flume first to remove the mud that hides lesions, inspection second so that what remains can actually be seen.
Related processes
Steps that sit alongside this one, replace it, or depend on it having been done.
Harvest
Fruit sorting
Taking rotten, mouldy and damaged fruit and foreign material out of the crop before it reaches the mill, which is the primary control on patulin in cider.
Fruit preparation
Milling
Reducing whole fruit to a pulp so that the press has cell walls it can drain, rather than intact apples it can only bruise.
Juice treatment
Sanitation
The cleaning and sanitising discipline that underlies every other process, and why removing soil must come before any attempt to kill organisms.
Orchard
Grazing under trees
Running livestock in an orchard so the sward becomes a second crop, with the tree protection, stock timing and food-safety rules that arrangement requires.
Juice treatment
Patulin control
Managing the mycotoxin produced by rot fungi in damaged apples, which is controlled by fruit selection rather than by any treatment applied to juice.
Harvest
Windfall management
Deciding which fruit that has reached the orchard floor can be used, and getting the rest out of the crop before it becomes a patulin problem.
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.
- How do i sterilise cider bottles — Wash them clean first, then sanitise with a no-rinse sanitiser or a sulphite solution, and fill while still wet with it. Bottles that look clean but have dried deposits inside are the usual source of bottle spoilage.
- Can you fix a cider that has gone vinegary — Not really. Volatile acidity cannot be removed at small scale, and blending it away only dilutes it. The realistic options are to accept it, to blend a lightly affected batch into a much larger sound one, or to let it finish becoming vinegar.
- What turns cider into vinegar — Acetic acid bacteria oxidising ethanol, in two steps that both consume oxygen. This is why acetification is an air problem: a full sealed vessel does not acetify however many bacteria it contains.
- 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.
Where to go next
- How cider is made — The whole sequence, stage by stage, with the choices open at each one.
- Cider science — The chemistry and microbiology the methods on this page rest on.
- Troubleshooting — What goes wrong, how to recognise it, and whether it can be reversed.
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.
European Food Safety Authority scientific opinions
EFSA · regulator · retrieved 2026-08-24
Registered for the food-safety questions cider genuinely raises: patulin in juice from rotten fruit, sulphite sensitivity, and the toxicology behind additive limits.