Glossary · Faults
Pinking
Definition
The development of a pink or salmon blush in a pale cider, usually after a period of oxygen exposure, arising from the oxidation of colourless phenolic precursors.
- Subject
- Faults
In more detail
Pinking is cosmetic and does not usually change the flavour, but it is unwelcome in a product sold on its pale colour. It is controlled by limiting oxygen pick-up at bottling and by fining with polyvinylpolypyrrolidone, which removes the precursors.
Where this is covered properly
The glossary defines; these pages explain. Each is described in its own words.
Related terms
Terms that belong to the same part of the subject, or that this one is routinely confused with.
Faults
Oxidation
The chemical damage done by oxygen to a finished cider: loss of fresh fruit aroma, browning, and the arrival of acetaldehyde, nutty and sherry-like notes.
Chemistry
Polyphenol
The broad class of plant compounds carrying multiple phenol rings. In apples this includes procyanidins, hydroxycinnamic acids such as chlorogenic acid, flavonols, dihydrochalcones such as phloridzin, and anthocyanins in red-fleshed fruit.
Fermentation
Fining
Adding an agent that binds haze-forming material and drags it out of suspension, so that the cider clears without filtration. Bentonite, gelatine, isinglass, chitosan and silica sol are common.
Chemistry
Dissolved oxygen
Oxygen carried in solution. Useful to yeast at the start of fermentation, and damaging afterwards, when it drives oxidation, acetification and the loss of aroma.
Where to go next
- Cider glossary — The whole vocabulary, by subject and A–Z.
- Comparisons — Terms that are only really clear when set against the thing they are not.
- Search — Finds terms by their aliases and by their spellings in other languages.
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.
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.