Glossary · Chemistry
Potential alcohol
Also written PA. Each is a name for the same thing, which is why none of them has an entry of its own.
Definition
The alcoholic strength a juice would reach if all its fermentable sugar were converted, estimated from the starting gravity.
- Subject
- Chemistry
- Also written
- PA
In more detail
The usual working rule divides the gravity points above 1.000 by a factor near 7.5 to give percentage alcohol by volume, so a juice at 1.050 offers roughly 6.6% ABV. The factor is an approximation: real yield varies with yeast strain, temperature, and how much sugar goes into glycerol and biomass rather than ethanol.
It is a ceiling rather than a prediction. Fermentations that stop early, are arrested, or are keeved finish well below it, and pear must contains unfermentable sorbitol that inflates the gravity without contributing alcohol.
Related terms
Terms that belong to the same part of the subject, or that this one is routinely confused with.
Chemistry
Specific gravity
The density of a liquid relative to water at the same temperature. In cider it is the routine measure of dissolved sugar before fermentation and of progress during it.
Fermentation
Attenuation
The proportion of the original sugar that fermentation has consumed, calculated from the fall in gravity from the starting to the current reading and expressed as a percentage.
Law and labelling
Alcohol by volume
The proportion of a drink’s volume that is pure ethanol at 20 degrees Celsius, expressed as a percentage. It is the figure labelling law requires on drinks above 1.2 per cent.
Chemistry
Sorbitol
A sugar alcohol present in substantial quantity in pears and in smaller amounts in apples. Yeast does not ferment it, so it survives fermentation and leaves a fully dry perry tasting faintly sweet.
Fermentation
Chaptalisation
Adding sugar to juice before fermentation to raise the eventual alcohol. It increases strength without changing acid or tannin, so a heavily chaptalised cider can taste thin for its strength.
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.
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.
Cornell Cider Research and Extension programme
Cornell University, School of Integrative Plant Science · university · passage verified 2026-08-24
Runs cultivar trials in New York State and publishes juice chemistry for European cider varieties grown in a North American climate — the single most useful counterweight to treating English figures as universal.