Glossary · Chemistry
Sorbitol
Also written glucitol. Each is a name for the same thing, which is why none of them has an entry of its own.
Definition
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.
- Subject
- Chemistry
- Also written
- glucitol
In more detail
Sorbitol commonly makes up a significant fraction of the soluble solids of perry pear juice — enough to matter both sensorially and analytically, since it raises the specific gravity without contributing to potential alcohol. A gravity-based estimate of a perry’s strength therefore overshoots unless the sorbitol is accounted for.
It also contributes body rather than just sweetness, which is part of why perry feels rounder than a cider of the same residual sugar. Certain lactic acid bacteria can metabolise it, which is one route into the disorders that afflict perry.
Where this is covered properly
The glossary defines; these pages explain. Each is described in its own words.
Chemistry
Sorbitol
The unfermentable sugar alcohol that pears carry in quantity and apples carry only in trace, and the single reason a fully fermented perry keeps a sweetness a fully fermented cider cannot.
Style
Perry
The fermented drink of pears, a tradition parallel to cider rather than derived from it, in which unfermentable sorbitol leaves a sweetness the maker never chose.
Related terms
Terms that belong to the same part of the subject, or that this one is routinely confused with.
Perry
Perry
A fermented alcoholic drink made from the juice of pears, and specifically from perry pears rather than dessert pears. It is not cider made with pears added: it is a separate drink with its own fruit, chemistry and problems.
Chemistry
Residual sugar
The fermentable sugar remaining in a finished cider, usually expressed in grams per litre. It is what sweetness legislation and style bands are written against.
Chemistry
Potential alcohol
The alcoholic strength a juice would reach if all its fermentable sugar were converted, estimated from the starting gravity.
Chemistry
Glycerol
A three-carbon polyol produced by yeast during fermentation, chiefly early on as it balances its internal redox state. It contributes slight sweetness and a sense of viscosity.
Perry
Pear must
Freshly pressed, unfermented pear juice destined for perry. It differs from apple must in its sorbitol content, its citric acid fraction and its lower assimilable nitrogen.
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.
Research on pear juice composition and sorbitol in perry
Various journals and institute reports · peer-reviewed literature · registered as competent for this subject
The evidence base for the single most important chemical difference between cider and perry: pears carry substantial sorbitol, which yeast does not ferment, so a fully fermented perry retains sweetness a fully fermented cider cannot.
Perry Pears
L. C. Luckwill and A. Pollard (eds), published for the National Fruit and Cider Institute by the University of Bristol, 1963 · reference work · bibliographic record verified, not opened 2026-08-25 · covers 1963
Bibliographic record verified on 2026-08-25 against Open Library, which records the work as Luckwill, 1963, published for the National Fruit and Cider Institute by the University of Bristol. The catalogue entry names Luckwill alone where the standard citation names Luckwill and Pollard as joint editors; CiderHQ keeps both names and records the discrepancy rather than silently following one catalogue. This is the foundational descriptive work on English perry pears and the ancestor of most later variety lists. No copy was opened: it is sixty years old, out of print, and held in research libraries rather than in open digital collections.