Compound
Starch
The fruit’s carbohydrate store, unfermentable until ripening converts it to sugar, and the reason picking early costs alcohol and risks a haze that will not clear.
- Class
- Polysaccharides
- Formula
- (C6H10O5)n
- How often it matters
- Occasional
What it does in cider
- Holds carbohydrate in an unfermentable form: yeast cannot use starch, so any that remains in the fruit at milling is alcohol the ferment never gets.
- Breaks down to glucose during ripening under the fruit’s own amylases, which is what the starch-iodine test tracks.
- Carries into juice from underripe fruit and forms a persistent colloidal haze that fining and filtration struggle with, because it is neither a protein nor a pectin.
- Gives a distinctive blue-black stain with iodine, providing the simplest and cheapest ripeness measurement available to an orchard.
What forms it
Processes that put this compound into the drink, or increase how much of it is there.
What removes or limits it
Processes that reduce it, hold it below a threshold, or stop it forming in the first place.
Ripeness assessment
Judging when cider fruit has converted enough starch, loosened enough on the spur and hardened enough for the store to be worth gathering.
Fruit storage before milling
Holding a gathered crop between harvest and the mill, and managing what respiration, water loss and spoilage do to it while it waits.
Sweating the fruit
Deliberately heaping or storing gathered fruit so that it softens, loses water and finishes converting starch before it goes to the mill.
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.
Starch haze
A persistent haze caused by starch carried in from under-ripe fruit, which has not yet been converted to sugar and stays suspended in the cider.
Thin body
A cider with no weight or texture in the mouth, most often from over-watered pomace, low-gravity juice or a blend with nothing to give it substance.
About Starch
An apple builds starch through the summer and dismantles it as it ripens, converting the polymer into glucose, fructose and sucrose. Picking sits somewhere on that curve, and where it sits has consequences on both sides. Pick too early and a measurable part of the potential alcohol is still locked up as starch, so the juice reads lower on the hydrometer than the fruit was capable of. Pick too late and the fruit softens, presses badly and starts to rot.
The starch-iodine test makes the curve visible. Iodine stains starch blue-black and leaves converted tissue unstained, so a halved apple dipped in iodine solution shows a pattern that moves progressively from a fully stained cut face to a clear one. Cider fruit is generally left considerably later than dessert fruit, which is why the same test is read against different expectations in a cider orchard.
Starch that does reach the juice is a nuisance out of proportion to its quantity. It forms a fine haze that behaves like neither protein nor pectin, so the usual remedies miss it: pectinase does nothing, gelatin and bentonite do little, and it will pass a coarse filter. The reliable prevention is not to press badly underripe fruit; the reliable cure, where one is needed, is amylase, and knowing which haze one has is the whole diagnostic problem, since a pectin haze and a starch haze look identical in the glass and are distinguished by an alcohol test and an iodine test respectively.
Related compounds
Compounds it is formed from, converted into, confused with, or routinely met alongside.
Sugars
Glucose
The sugar yeast takes first and the smallest of the three in apple juice, which is why the last sugar left in a slow ferment is almost never glucose.
Sugars
Fructose
The dominant sugar of apple juice and the sweetest of the common sugars, which is why apple juice tastes sweeter than its total sugar figure implies and why a stuck ferment leaves sweetness behind.
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.
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 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.
- Which sugar is most of the sugar in apple juice — Fructose, by a long way. Apple juice carries roughly twice as much fructose as glucose, with a smaller amount of sucrose, and fructose is the sweetest of the three on the tongue.
- When are cider apples harvested — In the northern hemisphere the cider harvest runs from about September to November, with late bittersweets such as Dabinett and Vilberie coming in last. Cider fruit is generally picked riper than dessert fruit, and often gathered from the ground.
- Does a sweeter cider have more calories
- Why is my cider thin and watery — Thin body usually follows from dessert-fruit juice with little tannin, over-dilution, aggressive filtration, or a ferment that stripped everything out. Body in cider comes mostly from tannin, glycerol and residual sugar.
- Do i need a filter to make cider
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.
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.
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.
NIAB (incorporating East Malling Research)
NIAB · research institute · retrieved 2026-08-24
East Malling developed the M-series apple rootstocks that determine tree size in essentially every modern orchard, cider orchards included. The authority CiderHQ uses for rootstock behaviour.