Compound
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.
Also called Pectinase, Polygalacturonase preparations.
- Class
- Enzymes
- Formula
- Not a single molecule — see below
- How often it matters
- Regularly encountered
What it does in cider
- Cleaves the pectin backbone, collapsing juice viscosity and releasing water held in the pomace.
- Destroys the pectin colloid, allowing suspended solids to flocculate and settle so that a juice clears and a filter runs.
- Raises extractable yield when applied to the pomace before pressing, and increases phenolic and colour extraction along with it.
- Rules out keeving: a juice whose pectin has been cut into fragments cannot form a calcium pectate raft.
What forms it
Processes that put this compound into the drink, or increase how much of it is there.
Pectinase treatment
Adding pectin-degrading enzyme preparations to juice so that haze-forming and viscosity-forming pectin is broken down before fermentation.
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.
What removes or limits it
Processes that reduce it, hold it below a threshold, or stop it forming in the first place.
Pasteurisation
Heating cider enough to inactivate the organisms that would spoil it, either in the sealed package or in-line before filling, at a measurable cost in fresh aroma.
Juice pasteurisation
Heat treatment of juice before fermentation, which inactivates enzymes and microorganisms, and in doing so removes the wild flora that would otherwise ferment it.
Faults it is implicated in
Being implicated is not the same as being a fault. Several of the compounds on this site are ordinary constituents of a sound cider and define a named fault only above a concentration.
Pectin haze
A persistent, slightly viscous haze that will not settle, caused by pectin from the fruit remaining in solution as a colloid.
Excessive sediment
More deposit in the bottle or vessel than the presentation intends, ranging from a normal conditioning yeast layer to a loose sludge that clouds every pour.
About Pectin lyase
Commercial pectinases are mixtures rather than single enzymes, combining lyase and polygalacturonase activities that cut the pectin backbone with esterase activity that de-methylates it, and often side-chain activities as well. Applied to pomace before pressing they raise yield substantially, because pectin is what holds water in the cake. Applied to juice afterwards they clear it, because destroying the pectin polymer destroys the colloid that was keeping fine solids in suspension.
For anyone making a bright, filterable cider this is close to indispensable, and it is why the alcohol test for residual pectin is a routine check: if a treated juice still forms clots when mixed with alcohol, the enzyme has not finished, and filtering will be a struggle.
The decision it forecloses is keeving. Keeving needs long pectin chains that can be de-esterified and then bridged by calcium into a floating gel. A pectinase has already cut those chains into pieces, and no amount of calcium will assemble fragments into a raft. A juice can be enzyme-treated or it can be keeved; it cannot be both, and this is one of the clearer forks in the road between industrial and traditional cider production.
One further caution belongs with the enzyme rather than the technique. Preparations that cut the backbone but leave the neutral side chains intact liberate free arabinans, which can associate weeks later into a haze in a product that was bright at packaging. Where that matters, the preparation needs the side-chain activities too.
Related compounds
Compounds it is formed from, converted into, confused with, or routinely met alongside.
Polysaccharides
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.
Acids
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.
Polysaccharides
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.
Enzymes
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.
Alcohols
Methanol
A small alcohol released not by fermentation but by enzymes stripping methyl groups off pectin, which is why juice handling rather than yeast choice governs how much a cider contains.
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 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.
- Why is there sediment in the bottom of my cider bottle — In a bottle-conditioned cider the sediment is yeast and is expected — pour carefully and leave the last centimetre. In a filtered cider it means something has grown since bottling.
- Is there methanol in cider — Yes, in small quantities: methanol is released when pectin in the fruit is broken down, and it is present in all fruit juices and fruit-based drinks. The concentration in cider is far below any level of concern, though it matters when cider is distilled.
- How is cider pasteurised
- Why add pectic enzyme to cider — Pectic enzyme breaks down the pectin that holds a haze in suspension and makes juice hard to press, so the cider clears and the yield rises. It must not be used where a keeve is intended, because keeving depends on the pectin staying intact.
Where to go next
- All compounds — Grouped by what the fruit brings and what the ferment makes of it.
- Sensory — Every descriptor, with the compound or process that causes it.
- Microbiology — The organisms whose metabolism most of this chemistry belongs to.
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.
Institut Français des Productions Cidricoles (IFPC)
IFPC · research institute · retrieved 2026-08-24
The French technical institute for cider production. The authority for the French cultivar classification families, for keeving as an industrial process, and for the pectin and nitrogen chemistry that keeving depends on.