Sensory descriptor
Banana
Isoamyl acetate at high concentration — the same molecule as pear drop, in different company and at a different level.
- Aroma family
- Tropical fruit
- Does it indicate a fault?
- It depends on the style it is met in
What causes it
Isoamyl acetate is the principal volatile of ripe banana and the principal ester of a warm, nitrogen-limited or aromatic-strain fermentation. Yeast makes isoamyl alcohol from leucine through the Ehrlich pathway, then esterifies it with acetyl-CoA via alcohol acetyltransferase; both steps are pushed by high fermentation temperature and by the amino-acid balance of the must. Above roughly 30°C the effect becomes pronounced, which is why banana is a reliable indicator of a ferment that ran hot. Some cultured strains express it strongly even at moderate temperature.
Below its independent recognition threshold isoamyl acetate simply lifts general fruit aroma and reads as ripe apple. Above it the perception tips to pear drop and then to banana, and at the top of the range it dominates every other volatile in the glass.
The compounds responsible
Where the molecule is established. Some descriptors in this lexicon name a compound the compound register does not yet hold a record for; those are named in the cause above instead.
Isoamyl acetate
The banana and pear-drop ester, made by yeast from isoamyl alcohol, and one of the clearest chemical signatures of a warm fermentation.
Isoamyl alcohol
The most abundant fusel alcohol in cider, made from leucine, and the direct precursor of the banana ester that defines warm-fermented styles.
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.
Amino acids
The largest usable nitrogen fraction in apple juice, and the raw material from which yeast builds both its own protein and most of the aroma compounds a cider carries.
What raises it
Processes that increase this character, or preserve it where it would otherwise be lost.
Fermentation temperature control
Managing the temperature at which a ferment runs, which sets not only how fast it goes but which aromatics survive it and what the finished cider tastes of.
Inoculated fermentation
Starting a ferment by pitching a chosen yeast culture so that one known strain, rather than the fruit’s resident population, does the work.
Yeast selection
Choosing which cultured strain to pitch, on the basis of the temperature, nitrogen, alcohol and aroma behaviour that separates one commercial yeast from another.
Yeast nutrition
What a fermenting yeast population actually needs from apple juice — assimilable nitrogen, vitamins and membrane lipids — and what goes wrong when the juice cannot supply it.
Where it is usually met
Fruit and styles this character is recorded in. A record here is where the descriptor is commonly found, not a claim that every example shows it.
About Banana
Banana is the most easily corrected fault-adjacent note in cider, because its cause is nearly always fermentation temperature and temperature is controllable. A producer meeting it has usually fermented in a warm room without cooling.
It is not a fault in itself and no fault slug applies. Whether it belongs depends entirely on the intended style, and it is expected in some warm-fermented traditions and out of place in a cider sold on fruit character.
Others in the tropical fruit family
Pineapple, mango, banana, passion fruit.
Bubblegum
A confected tropical note from acetate esters at high concentration with 2-phenylethanol behind them.
Passion fruit
A penetrating tropical-sulphur note from volatile thiols released by yeast β-lyase activity.
Pineapple
Sharp, sweet tropical fruit from short-chain ethyl esters, chiefly ethyl butanoate and ethyl hexanoate.
Mango
Soft, ripe tropical character from lactones and esters together, met in warm-climate and modern cultured ciders.
Melon
A soft, watery, faintly green tropical note from hexyl esters and residual nine-carbon aldehydes.
What people ask next
Questions readers ask about the things this page mentions. Each one goes to the section that answers it rather than to a page written to receive the question.
- What temperature should cider ferment at — Most cider is fermented cool, commonly between about 12 and 18 °C. Cooler ferments keep more fruit aroma and run slower; above the low twenties the cider tends towards hot, solvent-like higher alcohols.
- What yeast should i use for cider — CiderHQ does not recommend brands. The choice is between a neutral, reliable strain that lets the fruit show, an aromatic wine strain that adds its own esters, and no addition at all. Alcohol tolerance, cold tolerance and nitrogen demand are the properties worth comparing.
- Can you make cider from shop bought apple juice — Yes, provided the juice contains no preservative — check for potassium sorbate or benzoate on the label. Pasteurised juice ferments perfectly well once yeast is added, because pasteurisation removes the organisms but not the sugar.
- What is yeast nutrition in cider making
- How is supermarket cider made
- What are esters in cider — Esters are compounds formed when an acid and an alcohol combine, and they carry most of the fruity aroma in cider — banana, pear drop, apple, pineapple. Yeast makes them during fermentation, and warm ferments make more.
Where to go next
- The sensory model — The thirteen structural dimensions and the twenty aroma families, in full.
- Compounds — The chemistry behind the words.
- Troubleshooting — When a perception turns out to be a problem, this is where it is diagnosed.
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.
Hochschule Geisenheim University — beverage technology
Hochschule Geisenheim · university · retrieved 2026-08-24
German beverage-technology research covering apple wine and fruit juice processing, including the enzymology of clarification.