Compound
Quinic acid
The second acid of apple juice, better known as the part of chlorogenic acid that is not caffeic acid, and a small but real contributor to the astringent grip of cider fruit.
- Class
- Acids
- Formula
- C7H12O6
- How often it matters
- Occasional
What it does in cider
- Contributes a modest share of apple juice acidity, second to malic acid and roughly comparable to citric acid.
- Serves as the alcohol half of the two most abundant hydroxycinnamic esters in apple, chlorogenic acid and p-coumaroylquinic acid.
- Is released when those esters are hydrolysed, so its free concentration rises slowly through maturation.
- Adds a slightly astringent, drying quality distinct from the sourness of malic acid.
How it is perceived
What the compound registers as, and at roughly what concentration. Perception is not a property of the molecule alone: sugar, tannin and carbonation all change where a threshold falls.
- drying
- faintly astringent
- sour
The structure it moves
| Dimension | What it is |
|---|---|
| Acidity | The sharp, mouth-watering quality that makes a cider taste fresh rather than flat. |
| Astringency | The drying, rough sensation left after swallowing. |
Faults it is implicated in
Being implicated is not the same as being a fault. Several of the compounds on this site are ordinary constituents of a sound cider and define a named fault only above a concentration.
About Quinic acid
Quinic acid is a cyclohexane ring carrying a carboxyl group and four hydroxyls, and in apple juice it plays two roles at once. Free, it is an acid, sitting well behind malic acid in quantity but ahead of most others. Bound, it is the anchor for the fruit’s hydroxycinnamic esters: chlorogenic acid is caffeic acid esterified to quinic acid, and p-coumaroylquinic acid is p-coumaric acid esterified to the same molecule.
That double role means its concentration is not fixed. Esterase activity during fermentation and maturation, whether from the fruit, the yeast or lactic bacteria, slowly frees quinic acid from its esters, and the same reaction releases the cinnamic acids that Brettanomyces and certain lactic bacteria go on to convert into volatile phenols. Quinic acid is therefore a quiet marker of how far that chemistry has run.
On the palate it is minor but not absent, contributing a slight drying quality alongside its sourness. It belongs on the small list of compounds that explain why cider fruit tastes different from dessert fruit in ways that a total-acid figure does not capture.
Related compounds
Compounds it is formed from, converted into, confused with, or routinely met alongside.
Phenolics
Chlorogenic acid
The most abundant single phenolic in apple juice, the preferred substrate of the enzyme that browns it, and the precursor of one of the volatile phenols behind farmyard character.
Phenolics
p-Coumaroylquinic acid
The second most abundant hydroxycinnamic ester in apple, and the reservoir from which the p-coumaric acid behind 4-ethylphenol is slowly released.
Phenolics
Hydroxycinnamic acids
The family of small phenolic acids that browns a juice, and whose release from their esters supplies the raw material for every volatile phenol a cider can develop.
Acids
Malic acid
The acid of apples, which supplies almost all the sharpness a cider has and, through pH, decides how vulnerable that cider is to everything that could spoil it.
Acids
Shikimic acid
A trace acid that matters less for what it does in the glass than for what it is on the way to: every phenolic compound in cider is built through the pathway named after it.
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 is malic acid and why does it matter in cider — Malic acid is the acid of apples and supplies almost all the sharpness a cider has. It also sets pH, which decides how well sulphite works and how exposed the cider is to spoilage, so it does far more work than its taste suggests.
- What is chlorogenic acid in apple juice — It is the most abundant hydroxycinnamic acid in apples and the main substrate for enzymatic browning, so it is largely responsible for how brown a pressed juice goes and how quickly.
Where to go next
- All compounds — Grouped by what the fruit brings and what the ferment makes of it.
- Sensory — Every descriptor, with the compound or process that causes it.
- Microbiology — The organisms whose metabolism most of this chemistry belongs to.
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.
Institut national de recherche pour l’agriculture, l’alimentation et l’environnement (INRAE)
INRAE · research institute · retrieved 2026-08-24
French national agricultural research. Its Angers programme produced much of the published work on apple procyanidin chain length and on the relationship between polymer size, bitterness and astringency.