Green

Where this is covered properly

The glossary defines; these pages explain. Each is described in its own words.

• Chemistry

  Hexanal

  The green-apple aldehyde generated within seconds of breaking fruit tissue, which gives fresh juice its cut-grass smell and is largely converted away by the yeast.

Related terms

Terms that belong to the same part of the subject, or that this one is routinely confused with.

• Fruit

  Ripeness

  The stage at which fruit has completed starch conversion, reached its characteristic sugar and softened enough to press. For cider fruit it is judged later than for dessert fruit, often at or after natural drop.

• Milling and pressing

  Milling

  Breaking fruit down into pomace so that its cells rupture and its juice can be pressed out. It is the step that determines pressing yield more than any other.

• Chemistry

  Esters

  Compounds formed between an alcohol and an acid, produced in quantity by yeast during fermentation, and responsible for much of a cider’s fruity aroma.

• Sensory

  Astringency

  A tactile sensation of drying, roughening and puckering in the mouth, caused by tannins binding and precipitating the proteins that lubricate the oral surfaces. It is a feeling, not a taste.

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.

• Washington State University cider research programme

  Washington State University Northwestern Washington Research and Extension Center · university · passage verified 2026-08-24

  The single most useful open cider dataset CiderHQ has found. The programme’s cultivar performance database gives juice chemistry, orchard behaviour, bloom and harvest timing and cider-maker tasting notes for 73 cultivars grown at one maritime site over fifteen years, and — unusually — publishes its classification thresholds alongside its figures, so the classification can be checked rather than taken on trust. It also states outright that its results diverge from the English ones. Read in full on 2026-08-24 and transcribed into `data/trials/wsu-mount-vernon.ts`; four published figures were found to be impossible and are withheld there with their reasons.

• 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.