Compound
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.
Also called Arabinans, Neutral pectic side chains.
- Class
- Polysaccharides
- Formula
- Not a single molecule — see below
- How often it matters
- Specialist — met in particular circumstances
What it does in cider
- Decorates the branched regions of the pectin molecule as chains of arabinose units.
- Is released as a free polymer when a pectinase preparation cuts the pectin backbone without also carrying arabinanase activity.
- Slowly associates into a fine, persistent haze after clarification, producing the late-appearing turbidity that puzzles juice and cider processors.
- Passes through fining and ordinary filtration, so it is a formulation problem for the enzyme rather than a processing problem downstream.
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.
Sterile filtration
Membrane filtration at a rating that retains viable yeast and bacteria, which is what allows a sweet cider to be shelf-stable without heat or preservative — provided the filling that follows is aseptic.
Filtration
Passing cider through a porous medium to reach a stated visual brightness, at a real cost in colloidal material, body and aroma.
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.
About Arabinan
The pectin molecule is not a plain chain. Its rhamnose-interrupted regions carry side chains of neutral sugars, chiefly arabinose and galactose, projecting from the backbone like bristles. Ordinary pectinase preparations attack the backbone, which is what clarification needs — but if the preparation lacks arabinanase activity, the side chains come away intact as free arabinan polymers dissolved in what now looks like a bright juice.
Free arabinan is metastable. Over weeks it associates into fine particles, and a product that passed every clarity check at packaging develops a faint permanent haze in the warehouse. Because the material is neither protein, nor pectin in the sense the alcohol test detects, nor microbial, it defeats the standard haze diagnosis and gets blamed on everything else first.
The fix is upstream and unglamorous: use an enzyme preparation with the side-chain activities as well as the backbone ones, and give it time and temperature to finish. It is a small compound with a small story, and it is recorded here because a haze whose cause cannot be named is the kind of problem that gets solved by discarding good cider.
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.
Enzymes
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.
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.
- Do i need a filter to make cider
- 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.
- Pasteurising or sterile filtering — what is the difference
- Why add enzyme to apple pomace
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.