Glossary · Chemistry
Higher alcohols
Also written fusel alcohols, fusel oils. Each is a name for the same thing, which is why none of them has an entry of its own.
Definition
Alcohols larger than ethanol, formed by yeast from amino acids. In moderation they add complexity and a warm, slightly solvent note; in excess they read as harsh and heady.
- Subject
- Chemistry
- Also written
- fusel alcohols, fusel oils
In more detail
Production rises with fermentation temperature, with nitrogen imbalance and with yeast stress, so a hot, badly nourished ferment produces a coarser cider. Two of the most abundant, isoamyl alcohol and 2-phenylethanol, contribute banana-solvent and rose-honey characters respectively.
Where this is covered properly
The glossary defines; these pages explain. Each is described in its own words.
Chemistry
Higher alcohols
The group of larger alcohols yeast makes from amino acids, welcome as background complexity in trace and harsh and solvent-like in quantity.
Chemistry
2-Phenylethanol
The yeast-made alcohol responsible for the rose and honey note in cider, produced from phenylalanine and one of the few floral aromas that is not carried in from the fruit.
Related terms
Terms that belong to the same part of the subject, or that this one is routinely confused with.
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.
Fermentation
Fermentation
The conversion of sugar to ethanol and carbon dioxide by yeast, together with the many secondary reactions that occur alongside it and which supply most of a cider’s aroma.
Chemistry
YAN
The nitrogen a yeast can actually use — free amino nitrogen plus ammonium — expressed in milligrams of nitrogen per litre. Apple juice is frequently short of it.
Chemistry
Ethanol
The alcohol produced by fermentation and the compound that alcohol by volume measures. It contributes sweetness, warmth and body as well as intoxication.
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 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.
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.