Juice treatment
Pectinase treatment
Adding pectin-degrading enzyme preparations to juice so that haze-forming and viscosity-forming pectin is broken down before fermentation.
Also called Pectolytic enzyme addition, Enzyming the juice, Depectinisation.
- Stage
- Juice treatment
- Traditional in
- No single tradition — used wherever it suits
- What it most changes
- Body down, freshness up
- Safety
- None recorded
What it is
Commercial pectinase preparations are not a single enzyme but a mixture, typically of fungal origin, combining polygalacturonase, pectin lyase and pectin methylesterase along with incidental side activities. Dosed into juice after pressing, they take apart the pectin that apples carry in solution — the same polysaccharide that makes jelly set — converting a viscous, colloidally stable liquid into one that will drop bright and pass a filter. In cider making the treatment is applied to juice, sometimes also to pomace before pressing, and it is a defining fork in method rather than a routine addition.
Why it is used
- Untreated juice from many cultivars will not clarify: soluble pectin stabilises the haze, and no amount of settling time will fix a colloid that is thermodynamically happy where it is.
- Pectin makes juice viscous, which slows filtration to the point of impracticality and blinds filter media quickly; depectinised juice filters at a fraction of the effort.
- Where enzyme is applied to pomace before pressing, breaking down the cell-wall pectin releases bound juice and raises yield, particularly from soft or overripe fruit that presses poorly.
- A juice with no residual pectin cannot throw a pectin haze in the finished bottle, which removes one of the commonest causes of a cider that will not stay clear.
How it works
- Polygalacturonase hydrolyses the alpha-1,4 bonds of the galacturonic acid backbone, cutting the polymer into short fragments and free galacturonic acid; this is the activity that collapses viscosity.
- Pectin lyase cleaves the same backbone by beta-elimination and, unlike polygalacturonase, works directly on highly methylated pectin without needing it de-esterified first.
- Pectin methylesterase strips methyl ester groups from the backbone, exposing free carboxyl groups. On its own this makes pectin more gel-forming; in a mixed preparation it opens the chain to attack by polygalacturonase.
- Once the pectin sheath around suspended particles is gone, those particles lose their colloidal protection, aggregate and settle, so the juice clears by ordinary sedimentation.
- Side activities in commercial preparations — arabanase, cellulase, hemicellulase — degrade arabinan and other cell-wall polysaccharides that would otherwise cause a persistent secondary haze after the pectin has gone.
What it changes
The direction this step pushes the finished drink in, dimension by dimension. A direction, not a measurement: how far it moves depends on the juice, the temperature and how the step is carried out.
| Dimension | Direction | Why |
|---|---|---|
| Body | Lowers | Depolymerising a high-molecular-weight polysaccharide removes the solution viscosity and the colloidal load that contribute weight and slight cling to the palate. |
| Freshness | Raises | A bright, low-colloid juice ferments to a cider whose acidity and carbonation register cleanly rather than being buffered by suspended material. |
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
Pectin
The structural polysaccharide of fruit cell walls, which decides how much juice a press releases, whether a cider ever clears, and whether keeving is possible at all.
Pectin methylesterase
The enzyme that strips methyl groups from pectin, exposing the charged sites that calcium bridges — which is the reaction the whole of keeving is built on.
Pectin lyase
The chain-cutting activity in a commercial pectinase preparation, which raises press yield and clears a juice by destroying the colloid pectin creates — and destroys the possibility of keeving in the same stroke.
Galacturonic acid
The sugar acid that pectin chains are built from, released as they break down, and a significant part of why juice from rotten fruit binds so much of the sulphite added to it.
Arabinan
The branched neutral sugar side chains of pectin, which can be liberated intact by pectinase treatment and then form a haze that appears weeks after the juice looked perfectly clear.
What it is done with
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.
Styles it produces
Categories in which this step is characteristic or required. Some name it in their definition; for others it is simply how they have always been made.
Perry
The fermented drink of pears, a tradition parallel to cider rather than derived from it, in which unfermentable sorbitol leaves a sweetness the maker never chose.
Bottle-conditioned perry
Perry that completes its fermentation in the sealed bottle, generating carbonation and lees character while the fruit’s sorbitol keeps a sweetness the yeast cannot remove.
Keeved cider
Cider clarified before fermentation by a pectin gel that strips nutrients from the juice, producing a slow ferment that stops naturally with sugar still in solution.
Still perry
Perry without carbonation, in which the fruit’s sorbitol sweetness and its texture carry a drink that has no bubble to lean on.
Mostviertel Birnenmost
Austrian pear Most from the Mostviertel, made from the region’s tannic standard-tree perry pears, in which sorbitol leaves a soft sweetness no fermentation removes.
More on pectinase treatment
Apple pectin is a polymer of galacturonic acid, partly methyl-esterified, with side chains of arabinan and galactan. In juice it does two things a maker notices: it raises viscosity, and it wraps suspended particles in a hydrated layer that stops them coming together and falling. That is why a pectin-rich juice can sit for a week and remain as cloudy as the day it was pressed. A pectinase preparation attacks the backbone from more than one direction at once — hydrolytically by polygalacturonase, by beta-elimination through pectin lyase, and indirectly by de-esterification through pectin methylesterase, which opens methylated regions to the other two.
The consequence is a fork in method, and it is worth being blunt about it. Keeving depends on a native pectin methylesterase acting on pectin that stays intact: the enzyme de-esterifies the chain, the exposed carboxyl groups bind calcium, and the calcium pectate gel floats with the particulate and nitrogenous material trapped inside it to form the chapeau brun. Nothing about that works if the pectin has been depolymerised, because there is no long chain left to gel. Pectinase treatment is therefore the antithesis of keeving, not an alternative route to the same place, and a batch that has been enzymed cannot afterwards be keeved.
Practice varies accordingly. German Apfelwein production and large-scale juice technology generally, where the objective is a bright, stable, filterable product made to a schedule, treat depectinisation as routine and the associated yield gain from pomace treatment as straightforwardly worth having. Normandy keeving practice and English farmhouse making avoid it entirely, the first because it destroys the mechanism and the second because a slowly self-clarifying juice is part of the tradition. Many modern producers sit in between, enzyming batches destined for filtered products and leaving others alone. What a practitioner is really deciding is whether clarity is to be achieved chemically now, or by time and gravity later, or not at all.
Done badly, the failure modes are specific. Too little enzyme, or dosing into juice cold enough that activity crawls, leaves a partially degraded pectin that neither gels nor clears — the worst of both. Adding enzyme after sulphiting or alongside high solids can slow it further, and adding it to a juice already fermenting is largely wasted because ethanol and low pH cut the activity. On the sensory side, a thoroughly depectinised, brilliantly clear juice ferments to a cider that is noticeably leaner in the mouth than the same fruit fermented cloudy, which is a legitimate trade rather than a defect, but it should be a choice made knowingly.
Related processes
Steps that sit alongside this one, replace it, or depend on it having been done.
Juice treatment
Juice clarification
The deliberate use of enzyme, fining agents or mechanical separation to produce a bright juice before fermentation, and what that costs the ferment.
Fruit preparation
Enzyme addition to pomace
Dosing pectin-degrading enzyme into milled pomace rather than into juice, to raise press yield and change how the cake drains.
Fermentation
Keeving
Forming a floating pectin gel that lifts nutrients and solids out of the juice, so that the ferment starves before it finishes and leaves natural sweetness behind.
Juice treatment
Juice settling
Letting freshly pressed juice stand cold and undisturbed so that gross solids fall, then racking the cleaner juice off the deposit before pitching.
Stabilisation
Filtration
Passing cider through a porous medium to reach a stated visual brightness, at a real cost in colloidal material, body and aroma.
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.
- What is keeving — Keeving is a technique for starving a ferment of nitrogen so that it stops before all the sugar is gone, leaving a naturally sweet cider. Pectin is made to gel and float as a brown cap, carrying nutrients and yeast out of the juice with it.
- How do i clear a cloudy cider
- What does pectin do in cider — Pectin is the structural polysaccharide that holds fruit cells together. In juice it holds haze in suspension, and it is the molecule keeving depends on: strip its methyl groups and it will gel with calcium and float the nutrients out of the juice.
- Do i need a filter to make cider
- How is apple juice clarified before fermentation
- Where does the juice go between the press and the fermenter
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.
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 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.