Blending
Tannin balancing
Setting the phenolic structure of a blend, which means handling bitterness and astringency separately because they are different perceptions produced by different sizes of the same molecules.
Also called Phenolic balancing, Adjusting tannin.
- Stage
- Blending
- Traditional in
- No single tradition — used wherever it suits
- What it most changes
- Body up
- Safety
- None recorded
What it is
Tannin balancing is the adjustment of a cider’s phenolic fraction at blending: how much bittersweet or bittersharp material goes in, whether a coarse lot is diluted or a thin one reinforced, and whether the result is to be structured or soft. The fraction in question is the condensed tannins — procyanidins, oligomers and polymers of the flavan-3-ols epicatechin and catechin — and the reason it needs balancing rather than simply maximising is that these molecules produce two quite separate sensations, which respond differently to everything a blender can do.
Why it is used
- Phenolic content is what gives cider grip and length; a blend without it can be clean and correct and still feel like it stops short in the mouth.
- Too much of the wrong phenolic fraction is punishing rather than structural, and the remedy at blending is dilution with low-tannin material rather than any treatment applied later.
- Because bitterness and astringency are separable, a blend can be adjusted to carry the structure of tannin without the bitterness, or the reverse, by choosing components with different phenolic profiles.
- A cider destined for long ageing or for wood needs more phenolic material than one to be drunk young, because part of it will polymerise and drop out.
How it works
- Bitterness is a taste, transduced by receptors on the tongue, and is associated with the smaller phenolic molecules — monomers and short oligomers — which are small enough to reach the receptor sites.
- Astringency is a tactile sensation, not a taste: mid-sized procyanidins cross-link salivary proline-rich proteins and precipitate them, and the loss of lubrication is felt as drying and roughness.
- Because the two depend on molecular size in opposite ways, processes that change the size distribution — oxidative polymerisation, ageing, fining — move bitterness and astringency independently rather than together.
- Sugar and body suppress the perception of both, so an identical phenolic load reads as structure in a sweet or full-bodied cider and as harshness in a dry, thin one.
What it changes
The direction this step pushes the finished drink in, dimension by dimension. A direction, not a measurement: how far it moves depends on the juice, the temperature and how the step is carried out.
| Dimension | Direction | Why |
|---|---|---|
| Tannin | Either way | The phenolic load of the blend is set directly by the proportion of high-tannin fruit, so the dimension goes wherever the blender takes it. |
| Bitterness | Either way | Bitterness follows the smaller phenolic fraction specifically, so a blend can be made more or less bitter without a corresponding change in astringency. |
| Astringency | Either way | Astringency follows the mid-sized procyanidins that bind salivary protein, and is suppressed by sugar and by body independently of how much tannin is present. |
| Body | Raises | Phenolic material contributes to the colloidal load and to the tactile impression of the cider, so raising tannin generally raises perceived weight as well. |
The chemistry and the organisms
What is actually being changed, and by what. Each entry says what that compound or organism does in cider generally; this page is one place it does it.
Compounds involved
Procyanidins
The condensed tannins of cider fruit, whose chain length — not their quantity — decides whether the mouth registers bitterness or astringency.
Epicatechin
The flavan-3-ol that apple procyanidins are almost entirely built from, and the most bitter of the phenolic monomers a cider contains.
Catechin
The minor flavan-3-ol of apple, present largely as the terminal unit of procyanidin chains, and consequently a useful analytical handle on chain length.
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.
Tannin–protein complexes
What astringency physically is: long tannin chains cross-linking salivary proteins and precipitating them, which is also the mechanism behind fining, protein haze and the classic cider-and-cheese pairing.
Phloridzin
A dihydrochalcone found in apple and essentially nowhere else, which makes it both a contributor to bitterness and the standard chemical proof that a juice is apple juice.
What it is done with
What can go wrong
Faults that begin at this step, or that this step makes more likely. Each one is set out with its causes and whether it can be put right.
Excessive bitterness
Bitterness that dominates the palate rather than supporting it, usually from a blend weighted too heavily towards high-tannin fruit or extracted too hard.
Excessive astringency
A drying, roughening, mouth-puckering sensation that outstays its welcome, produced by larger phenolic polymers precipitating salivary proteins.
Thin body
A cider with no weight or texture in the mouth, most often from over-watered pomace, low-gravity juice or a blend with nothing to give it substance.
Protein haze
A fine haze that forms as protein and tannin combine into insoluble complexes, often appearing in a cider that had already been clear.
Styles it produces
Categories in which this step is characteristic or required. Some name it in their definition; for others it is simply how they have always been made.
West Country farmhouse cider
Cider made on the farm from tannic bittersweet fruit, wild-fermented in wood and sold still and unfiltered, in a tradition whose variability is one of its defining features.
Somerset cider
Cider from the Somerset levels and the surrounding hills, built on a locally selected bittersweet fruit population and a tradition of full-bodied, tannic, still cider.
Herefordshire cider
Cider from the county with England’s largest cider orchard area, protected as a geographical indication and spanning farmhouse practice, bottle-fermented cider and industrial-scale production.
Cidre de Normandie
Protected Normandy cider made from the region’s bitter and bittersweet fruit, characteristically low in alcohol, sweet-edged and lightly sparkling.
Single-varietal cider
Cider made wholly or overwhelmingly from one apple cultivar, presented so that the fruit’s own character is the subject of the drink.
Blended cider
Cider assembled from several cultivars, parcels or vintages so that the finished balance is a made decision rather than an inherited one.
More on tannin balancing
The single most useful thing a blender can learn about tannin is that bitterness and astringency are not the same thing and do not have to be traded against each other. Bitterness is a gustatory response to comparatively small molecules — flavan-3-ol monomers and short oligomers — that can reach and activate bitter receptors. Astringency is mechanical: larger procyanidins bind and precipitate the proline-rich proteins in saliva, saliva loses its lubricating property, and the resulting friction is felt across the whole mouth rather than tasted at a point. Because the two depend on molecular size in opposite directions, a cider can be markedly bitter and barely astringent, or drying without being bitter at all, and the fruit that produces each is different. Norman and English classifications reflect this in practice: growers and makers have long distinguished varieties whose tannin is hard from those whose tannin is soft, which is a size distribution described in sensory language.
What follows for blending is that dilution is not the only tool. Diluting a phenolic lot with a low-tannin one reduces both sensations proportionately, which is sometimes exactly right and sometimes wastes the structure along with the harshness. The alternatives work on the size distribution or on the context. Fining with a protein agent removes preferentially the fraction that binds protein, which takes out astringency ahead of bitterness. Oxidative ageing polymerises tannins past the astringent size range. And because both perceptions are suppressed by sweetness and by body, a blend that is unmanageably hard when dry can be entirely coherent with residual sugar in it — which is one reason so many high-tannin traditions arrive at medium or sweet ciders rather than dry ones.
The failure modes are asymmetric, and this shapes how a blender should approach the work. A blend that is short of tannin can be corrected by adding a tannic component, provided one exists in the cellar. A blend that is over-tannic can only be diluted, and dilution costs everything else the tannic lot was contributing. So the sensible order is to build up from the less phenolic base towards the target rather than to start from the tannic lot and pull it back. The other trap is judging tannin in a young cider as though it were finished. Phenolics polymerise and precipitate over months, and a blend assembled to taste correctly on the day it is made will often be softer than intended by the time it is packaged, particularly if it goes into wood.
Related processes
Steps that sit alongside this one, replace it, or depend on it having been done.
Blending
Blending
Combining separate lots of cider or perry into one, which in cider is the historically normal way of making the drink rather than a remedy applied when single lots disappoint.
Stabilisation
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.
Blending
Bench blending trials
Making small measured mixtures of candidate lots and tasting them before committing tanks, because how components behave together cannot be worked out from how they taste apart.
Blending
Acid balancing
Bringing a cider to the sharpness it needs, which requires separating perceived sharpness from titratable acidity from pH — three related things that do not move together.
Blending
Back-sweetening
Adding sugar, juice or concentrate to a cider that has fermented dry — a straightforward adjustment that leaves the drink microbiologically unstable until something is done about it.
Maturation
Oxidative maturation
Ageing a cider with a deliberate, measured oxygen supply so that tannins polymerise and soften and an aldehydic character develops on purpose, which is not the same thing as the oxidation fault.
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.
- 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.
- How do i balance acid and tannin in a blend — Acid and tannin do different jobs and cannot substitute for each other: acid gives freshness and microbiological safety, tannin gives structure and length. A blend short of acid tastes flabby however tannic it is.
- How do i make my cider sweeter
- How do you blend cider
- What are procyanidins in cider — They are the condensed tannins of apples: chains of catechin-type units whose length decides how much of the phenolic load reads as bitterness and how much as astringency. Two ciders with identical total tannin can taste nothing alike.
- What is the difference between french cidre and english cider — French cidre is usually sweeter, weaker and more carbonated, because fermentation is arrested while sugar remains. English cider is more often fermented dry and finished still or lightly sparkling, and is stronger for it.
Where to go next
- How cider is made — The whole sequence, stage by stage, with the choices open at each one.
- Cider science — The chemistry and microbiology the methods on this page rest on.
- Troubleshooting — What goes wrong, how to recognise it, and whether it can be reversed.
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.
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.
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.
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.