Compound
Anthocyanins
The red pigments of apple skin and red-fleshed cultivars, which are colour rather than flavour and which fade quickly in a cider unless the pH is low.
- Class
- Phenolics
- Formula
- Not a single molecule — see below
- How often it matters
- Specialist — met in particular circumstances
What it does in cider
- Colours apple skin red and, in red-fleshed cultivars, the flesh itself.
- Changes colour with pH, appearing red in acid conditions and shifting towards blue and grey as pH rises, so a low-acid cider holds pink far less well than a sharp one.
- Binds sulphur dioxide reversibly, which bleaches the colour — a sulphited pink cider looks paler than its pigment content suggests and recovers as free SO2 falls.
- Contributes essentially nothing to taste or aroma at the concentrations cider reaches.
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.
- colour only
Anthocyanins are visual rather than gustatory at cider concentrations. What a drinker reads as red-fruit flavour in a pink cider comes from added fruit or from esters, not from the pigment.
Descriptors it is responsible for
Sensory records that name Anthocyanins as a cause. Each states the perception and the mechanism behind it.
- Red fruit — A general soft red-berry impression from medium-chain ethyl esters, most often met in tannic ciders with some age.
The structure it moves
| Dimension | What it is |
|---|---|
| Fruit character | How strongly the drink smells of apple or pear, and of fruit generally. |
What forms it
Processes that put this compound into the drink, or increase how much of it is there.
Fruit addition
Bringing fruit other than apple or pear into a cider as juice, purée, whole fruit or concentrate, where the timing of the addition decides whether you keep the aroma or the alcohol.
Maceration
Holding milled pomace before pressing so that phenolics, aroma precursors and pectin have time to move out of the solid tissue and into the juice.
What removes or limits it
Processes that reduce it, hold it below a threshold, or stop it forming in the first place.
Sulphiting
Adding sulphur dioxide to juice to suppress spoilage organisms and oxidative browning, at a level that only means anything once the juice pH is known.
Fining
Adding a reactive agent that binds a target colloid and carries it to the bottom, chosen according to whether the problem is tannin, protein or a phenolic taste fault.
Filtration
Passing cider through a porous medium to reach a stated visual brightness, at a real cost in colloidal material, body and aroma.
Juice oxidation
The enzymic browning that begins the moment apple juice meets air, which some traditions deliberately allow and others suppress.
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.
Colour loss
A cider left noticeably paler than it should be, usually because fining, filtration or sulphite has removed the phenolic material that gave it colour.
Pinking
An unexpected pink or salmon tint developing in a pale cider or perry, associated with oxidation of colourless phenolic precursors.
Light strike
A skunky, cooked-cabbage or drain-like aroma produced when light acting on riboflavin generates sulphur compounds in a bottle.
About Anthocyanins
Anthocyanins are the flavonoid pigments responsible for red in apple skin and for the colour of red-fleshed cultivars. In a conventional cider almost none of them survive into the glass, because they live in the skin and are largely removed with the pomace and the lees. In a cider made from red-fleshed fruit, or a fruit cider with berry addition, they are the colour.
Their behaviour is governed by pH and by sulphite. The pigment exists in several forms in equilibrium, and only the flavylium cation is strongly red; as pH rises the equilibrium moves towards colourless and bluish forms, so the same pigment concentration gives a bright pink cider at pH 3.2 and a dull greyish one at pH 3.9. Sulphur dioxide adds reversibly to the pigment and bleaches it, which is why a freshly sulphited pink cider looks washed out and regains colour over the following weeks as free SO2 falls.
They are also fugitive. Light, oxygen and time all degrade them, and a pink cider stored in clear glass on a bright shelf loses its colour visibly within months. This is a presentation problem rather than a flavour one, but it is the reason colour stability is a real technical concern in the fruit-cider category and not in ordinary cider.
Related compounds
Compounds it is formed from, converted into, confused with, or routinely met alongside.
Phenolics
Quercetin glycosides
The yellow flavonols of apple skin, made in response to sunlight, which contribute a fine astringency and reach the juice only in proportion to how much skin was pressed.
Phenolics
Total phenolics
The single number used to summarise everything phenolic in a juice, useful for comparing fruit and misleading whenever it is used to predict how a cider will taste.
Additives and processing aids
Sulphur dioxide
The antimicrobial and antioxidant on which most modern cidermaking depends, and whose effectiveness collapses as pH rises — which makes every sulphiting decision a pH decision first.
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.
- Does cider contain sulphites — Most does. Sulphur dioxide is added to protect juice and finished cider, and fermentation itself produces a small amount even when none is added. European labels must declare it above 10 mg per litre.
- Is cider vegan — Cider itself is a plant product, but some producers clarify it with animal-derived finings such as gelatine, isinglass or chitosan. Vegan status therefore depends on the fining regime, which is why some ciders are certified and others are not.
- Why is sulphite added to cider — Sulphur dioxide suppresses spoilage bacteria and wild yeast before fermentation and protects the finished cider from oxidation. How much of it is active depends strongly on pH, which is why low-acid juice is harder to protect.
- Does cider contain antioxidants — Cider carries apple polyphenols, and tannic bittersweet ciders carry considerably more than pale ones made from dessert fruit. What that means for health is a clinical question this site does not adjudicate.
- Does cider need to be kept out of the light — Yes, particularly in clear or green glass. Light reacts with riboflavin and sulphur compounds to produce a skunky aroma within hours of direct sunlight.
- Do i need a filter to make cider
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.
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.
Peer-reviewed literature on apple phenolics and cider sensory perception
Various journals · peer-reviewed literature · registered as competent for this subject
Registered as a class rather than as one paper, because the mechanisms CiderHQ describes — tannin chain length driving the split between bitterness and astringency, salivary protein precipitation, enzymatic browning — are established across many studies rather than resting on any single one. Individual papers are cited where a specific number is quoted.
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.