Carbonation
Bottle conditioning
Carbonating cider by letting a second fermentation finish inside the sealed bottle, so the gas is generated where it is going to stay.
Known as Prise de mousse where it originates. Also called Bottle fermentation, Conditioning in bottle.
- Stage
- Carbonation
- Traditional in
- Herefordshire, Gloucestershire, Somerset, Normandy and 4 more
- What it most changes
- Carbonation up, body up
- Safety
- Carries a safety consideration — see below
Bottle conditioning deliberately generates pressure inside glass, and the hazard is real. The controlling variable is total fermentable sugar in the bottle, which includes both anything added at bottling and anything the primary ferment left behind — misjudging the second is the usual cause of a burst. Use bottles rated for internal pressure and closures that will hold it, keep conditioning and stored stock cool, wear eye protection when handling or opening suspect bottles, and never bottle a cider whose primary fermentation has not finished or been deliberately arrested and verified. A cider that gushes on opening should be treated as over-pressured across the whole batch, not as one odd bottle.
What it is
Bottle conditioning carbonates cider by sealing it in the bottle while fermentable sugar and viable yeast are both still present, and letting the fermentation complete there. The carbon dioxide produced has nowhere to go: the pressure in the headspace rises until the gas dissolves into the liquid, and the bottle reaches equilibrium at a carbonation level set by how much sugar was fermented, how large the headspace is and how warm the bottle is kept. A sediment of spent yeast is left in the bottle unless it is removed by disgorging. It is the oldest method of making cider sparkle and it remains the defining technique of several styles across England, France, Spain and North America.
Described in full
- Layout
- Four rows, one per method, each broken into three steps read left to right. The steps are what distinguishes the methods; the finished gas level can be identical.
- Bottle conditioning
- A measured sugar addition, then sealing, then a warm rest while the remaining yeast ferments it. The gas has nowhere to go but into solution. Yeast sediment stays in the bottle, so the cider is cloudy if poured carelessly.
- Tank conditioning
- The same refermentation done in a sealed pressure tank rather than in each bottle. The tank holds the gas, the cider can then be filtered clear, and it is filled into bottles under counter-pressure so nothing is lost.
- Traditional method
- Bottle conditioning followed by riddling and disgorging: the sediment is worked into the neck, the neck frozen, and the plug of ice expelled. The result is bottle-fermented and brilliantly clear, at the cost of a great deal of handling.
- Forced carbonation
- No fermentation at all. The cider is chilled, carbon dioxide is injected until it dissolves to the target, and it is filled under pressure. Fast, exactly repeatable, and the only method that lets gas level be chosen independently of everything else.
- What differs in the glass
- Conditioned ciders carry finer, more persistent bubbles and a trace of yeast character; forced carbonation gives a coarser bead that dissipates faster. The difference is real but smaller than the difference between two ciders.
- The sediment question
- Only bottle conditioning leaves sediment in the bottle as a matter of course. Whether that counts as a flaw or as evidence of method depends entirely on the tradition being judged against.
Why it is used
- It carbonates without any gas-handling equipment, which is why it was the only method available for the first three centuries of sparkling cider and remains the practical one at small scale.
- The cider matures on the yeast in the bottle, and that contact contributes texture and foam stability that injected gas does not.
- For makers whose cider still contains its own residual sugar, it turns the natural end of the fermentation into the carbonation rather than requiring anything to be added.
- It is what several style definitions and consumer campaigning categories mean by a live, unpasteurised product.
How it works
- Yeast ferments the available sugar to ethanol and carbon dioxide in the usual way, but in a sealed container the gas cannot escape, so it accumulates and dissolves.
- The relationship is close to stoichiometric: a given mass of fermentable sugar yields a predictable mass of carbon dioxide, and that mass distributes between the liquid and the headspace according to temperature and pressure.
- Solubility falls as temperature rises, so the same bottle carries a much higher pressure warm than cold — a bottle conditioned in a cool cellar and then stored in a warm room has not changed its gas content, only where that gas is sitting.
- The yeast flocculates and settles once the sugar is gone, and then slowly autolyses, releasing mannoproteins and amino acids that affect mouthfeel and foam.
- The sediment is either left in the bottle and accepted as part of the product, or removed by riddling the yeast into the neck and disgorging it under pressure.
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 |
|---|---|---|
| Carbonation | Raises | The gas is generated inside the sealed package and has no escape, so it dissolves into the cider until liquid and headspace reach equilibrium. |
| Body | Raises | Extended contact with the settled yeast releases mannoproteins and other autolysis products that add textural weight and stabilise the foam. |
| Freshness | Either way | Dissolved carbon dioxide sharpens the perception of acidity and lift, while the months on lees that bottle conditioning implies move the drink away from primary fruit character. |
| Fermentation character | Raises | A second fermentation and the autolysis that follows it add yeast-derived aroma on top of whatever the primary ferment produced. |
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
Carbon dioxide
The other product of fermentation, which protects a cider from air while it is being made and, dissolved in the finished drink, changes both its texture and its perceived acidity.
Ethanol
The alcohol yeast makes from fruit sugar, which converts a perishable juice into a keepable drink and carries most of its aroma to the nose.
Glucose
The sugar yeast takes first and the smallest of the three in apple juice, which is why the last sugar left in a slow ferment is almost never glucose.
Fructose
The dominant sugar of apple juice and the sweetest of the common sugars, which is why apple juice tastes sweeter than its total sugar figure implies and why a stuck ferment leaves sweetness behind.
Sucrose
The disaccharide of apple juice and the sugar most often added to it, split into glucose and fructose by the yeast’s own invertase before any of it is fermented.
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.
Acetaldehyde
The compound sitting one step short of ethanol, which smells of bruised apple and sherry, binds most of the sulphite added to a cider, and is the chemical signature of oxidation.
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.
Organisms involved
Saccharomyces cerevisiae
The yeast that finishes essentially every cider, whether it arrives in a sachet or from the fruit, the press and the vessel.
Saccharomyces bayanus
A name applied both to a hybrid Saccharomyces lineage and, loosely, to a whole class of commercial high-alcohol yeasts, and one of the least stable names in fermentation microbiology.
Saccharomyces uvarum
A cold-tolerant relative of S. cerevisiae recovered from spontaneous cider and wine ferments, associated with low-temperature fermentation and higher glycerol.
Oenococcus oeni
The acid-tolerant lactic acid bacterium that carries out most deliberate malolactic fermentation, converting malic acid to lactic acid after the yeast has finished.
Dekkera bruxellensis
The yeast behind 4-ethylphenol, and the organism that a cider tradition may regard as its signature or its ruin depending on where and how it is made.
Where it is traditional
The places this step belongs to as a matter of practice. It is not a claim of exclusivity — a method can be traditional in one region and perfectly ordinary in another.
What it is done with
Bottles and pressure: what glass will and will not hold
Sparkling-wine bottles are engineered and tested to hold several atmospheres; still-wine bottles are not engineered to hold any, and filling one with a carbonating cider is the most dangerous ordinary mistake in home cider making.
Crown caps, swing tops and the tools that fit them
The crown cap is a crimped steel cap with a compressible liner, the cheapest reliable pressure closure ever devised; the swing top is a reusable stopper held by a wire bail, convenient and dependent entirely on the condition of its gasket.
Corks, agrafes and muselets
A sparkling closure is a cork compressed to a fraction of its diameter and driven into the neck, held there by a metal clip during conditioning or by a wire muselet once finished — because the pressure inside would otherwise push it out.
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.
Bottle over-carbonation
More dissolved carbon dioxide in the bottle than intended or than the glass is rated for — a presentation problem at the mild end and a physical hazard at the severe one.
Gushing
Cider that erupts from the bottle on opening, either because it is over-pressurised or because something in it is nucleating the dissolved gas violently.
Under-carbonation
A cider intended to sparkle that has little or no dissolved gas, usually because the bottle conditioning never started or the closure did not hold.
Excessive sediment
More deposit in the bottle or vessel than the presentation intends, ranging from a normal conditioning yeast layer to a loose sludge that clouds every pour.
Unwanted refermentation
Fermentation restarting in a sealed container, generating carbon dioxide that was not planned for and pressure that a bottle may not withstand.
Yeast haze
Cloudiness from yeast cells that have not settled out, usually because the strain flocculates poorly or the cider has not been left alone long enough.
Light strike
A skunky, cooked-cabbage or drain-like aroma produced when light acting on riboflavin generates sulphur compounds in a bottle.
Oxidation
The cumulative effect of oxygen on finished cider: fruit aroma flattens, colour deepens towards amber, and a bruised-apple or sherry-like character replaces the fresh one.
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.
Bottle-conditioned cider
Cider that completes a fermentation inside its sealed bottle, generating its own carbonation and, in most cases, leaving a yeast deposit behind.
Bottle-conditioned perry
Perry that completes its fermentation in the sealed bottle, generating carbonation and lees character while the fruit’s sorbitol keeps a sweetness the yeast cannot remove.
Sparkling cider
Cider carrying enough dissolved carbon dioxide to produce a persistent bubble, by bottle fermentation, tank fermentation or injection.
Pétillant cider
Lightly carbonated cider in which the gas is felt as a prickle rather than a stream of bubbles, the level most traditional bottle fermentation reaches on its own.
Sparkling perry
Perry carrying a persistent bubble, a presentation that suits pear’s aromatics and residual sorbitol and has a documented history going back to the seventeenth century.
Cidre de Normandie
Protected Normandy cider made from the region’s bitter and bittersweet fruit, characteristically low in alcohol, sweet-edged and lightly sparkling.
Cidre Pays d’Auge
The controlled appellation cider of the Pays d’Auge in Calvados, made by keeving from bitter Norman fruit and bottle-conditioned to a low alcohol and a high residual sugar.
Sidra espumosa
Sparkling Asturian cider made by a second fermentation under pressure or in bottle, presented as a fine sparkling drink rather than in the still poured tradition.
Keeved cider
Cider clarified before fermentation by a pectin gel that strips nutrients from the juice, producing a slow ferment that stops naturally with sugar still in solution.
American heritage cider
Cider made from the North American heirloom cultivars that survived the collapse of the country’s cider industry, and presented as an expression of that recovered fruit.
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.
Poiré
French perry, made chiefly in southern Normandy and Maine from local perry pears, characteristically sweet, low in alcohol and firmly sparkling.
Poiré Domfront
The controlled appellation perry of the Domfrontais in southern Normandy, made predominantly from the Plant de Blanc pear on high-standard trees and finished sweet, low in alcohol and bottle-conditioned.
Three Counties cider
The shared cider and perry tradition of Herefordshire, Gloucestershire and Worcestershire, defined by a common fruit inventory and by the perry pear orchards that survive nowhere else in comparable numbers.
Cidre brut
The dry tier of the French cider scale, defined since 2025 by a density no greater than 1.016 with an acquired strength of at least 3.5% vol — correspondingly more of the juice’s sugar converted to alcohol.
Cidre de Bretagne
Protected Breton cider, built on a distinct western fruit inventory and generally drier, lighter and more acid-led than its Norman counterpart.
Cidre demi-sec
The middle tier of the French cider scale, sitting between doux and brut on density and forming the commercial centre of ground for much French cider.
Cidre doux
The sweet tier of the French cider scale, defined since 2025 by a density at or above 1.024 together with an acquired strength no greater than 3% vol, so that the sweetness is demonstrably unfermented juice sugar.
Cidre fermier
Farm-made French cider, pressed and fermented on the holding that grew the fruit, sold as an agricultural product of that farm rather than as a regional or industrial one.
Tasmanian cider
Cider from Tasmania, whose cool maritime climate and long apple-growing history give fruit with the acid that most Australian districts cannot hold.
Welsh cider
Cider from Wales, rebuilt over recent decades from a nearly lost tradition, with protected names for traditional Welsh cider and perry and a fruit inventory shared with the English border counties.
More on bottle conditioning
The mechanism is the ordinary alcoholic fermentation moved into a container that will not let the gas leave. Yeast converts sugar to ethanol and carbon dioxide; in an open vat the carbon dioxide simply goes, and in a sealed bottle it cannot, so pressure builds in the headspace until the partial pressure of the gas above the liquid is high enough to force it into solution. The equilibrium that results depends on three things the maker controls — the quantity of fermentable sugar, the volume of headspace, and the storage temperature — and on one they do not, which is whether the yeast is healthy enough to finish the job. Everything that makes bottle conditioning either successful or dangerous follows from that short list.
Historically this is where sparkling cider begins. Worlidge’s account of English practice in 1676 already describes bottling cider before it had finished, in strong glass, and the sparkle that resulted — a full generation before the conventions of Champagne were settled. English glass of the period was unusually strong, which is part of why the practice took hold here first. That thread runs forward into the bottle-conditioned ciders and perries of Herefordshire and Gloucestershire, into the Norman prise de mousse in bottle, and, by a separate route, into the Asturian and Basque bottled sparkling ciders. It is the same physics in each case, but not the same product: what the maker starts with, and whether anything is added, differs completely.
That difference is the real fork in the road. One route bottles a cider that still holds its own unfermented sugar — a keeved cidre doux, or a cider racked repeatedly until the ferment slowed — and lets what remains carry the carbonation. Nothing is added, and the maker is estimating rather than measuring the fermentable reserve, which makes the outcome inherently less certain and the pressure risk higher. The other route ferments the cider fully dry, confirms it is dry, and then adds a measured amount of sugar or juice at bottling, which is priming. Both are traditional; only the second is calculable. A third variant, the traditional method, bottle-ferments with the express intention of removing the sediment afterwards by riddling and disgorging, which turns a rustic technique into a considerably more exacting one.
Failure has two shapes and they point in opposite directions. Under-carbonation comes from yeast that cannot do the work: a population exhausted by the primary ferment, sulphited too heavily at bottling, chilled below its working range, or starved of the nitrogen a second fermentation still requires. The bottles sit flat and there is no remedy short of opening and re-doing them. Over-carbonation comes from more fermentable sugar than the maker thought was there, and it is the dangerous one — bottles gush, and glass that is not rated for the pressure can fail. Between the two sits the ordinary annoyance of sediment, which is intrinsic to the method and which producers either present as a feature of a live product, ask the drinker to pour carefully around, or remove by disgorging. Bottle-conditioned cider is also unusually sensitive to light and to warm storage, so the conditions the trade keeps it in matter as much as anything the maker did.
Related processes
Steps that sit alongside this one, replace it, or depend on it having been done.
Carbonation
Priming
Adding a measured, calculable quantity of fermentable sugar at bottling so that the fermentation which follows generates a predictable volume of carbon dioxide.
Carbonation
Natural carbonation
Bottling before the primary fermentation has finished, so the sugar still in the cider produces the carbonation with nothing added and nothing restarted.
Carbonation
Traditional method
A second fermentation in the bottle the cider will be sold in, followed by riddling the deposit into the neck and expelling it, so the drink is both bottle-fermented and clear.
Carbonation
Transfer method
Fermenting in bottle for the character, then emptying the bottles under counter-pressure into a tank, filtering and refilling to remove the deposit without riddling.
Carbonation
Tank conditioning
Running a second fermentation in a sealed pressure tank so the gas is generated by yeast but the sediment never reaches the bottle.
Packaging
Bottle pressure management
Matching the pressure a carbonated cider will actually generate to glass that can contain it, taking account of temperature and of any fermentable sugar left in the bottle.
Packaging
Closure selection
Choosing between cork, crown, screwcap, cage and swing-top, a decision that fixes how much oxygen reaches the cider, whether it can hold pressure, and which faults it is exposed to.
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.
- How much pressure builds up in a bottle of cider — Enough to matter. Every gram of sugar fermented in a sealed bottle produces gas, and a bottle not rated for it can fail. The French cider appellations require a minimum of 1.0 to 1.5 bar at 20 °C, and a bottle-conditioned cider can go well beyond that if it was filled with more sugar than intended.
- What is priming sugar — Priming sugar is a measured dose of sugar added at bottling so that the remaining yeast produces carbon dioxide inside the sealed bottle. Too much of it is the usual cause of burst bottles.
- 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.
- How many calories are in cider — Roughly 40 to 60 kcal per 100 ml for most ciders, so a UK pint falls somewhere around 200 to 250 kcal. Alcohol contributes about 7 kcal per gram and residual sugar about 4, so both strength and sweetness matter.
- Which yeast ferments cider — Saccharomyces cerevisiae finishes almost every cider fermentation, whether it was pitched or arrived from the press house. In a spontaneous ferment it is not the first organism present, only the one that survives the alcohol it makes.
- Why did my cider bottles explode — Because fermentable sugar was still present, or too much priming sugar was used, and the pressure exceeded what the bottle could hold. Never bottle a cider whose gravity is still falling, and never use bottles not designed for pressure.
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.
The New Cider Maker’s Handbook: A Comprehensive Guide for Craft Producers
Claude Jolicoeur, Chelsea Green Publishing, 2013. ISBN 9781603584739 · reference work · bibliographic record verified, not opened 2026-08-25
Bibliographic record verified on 2026-08-25 against the Open Library union catalogue: Chelsea Green Publishing, 2013, ISBN 9781603584739, one edition recorded. That establishes the citation points at a real book in a stated edition, which is what a citation needs and is all it establishes. No copy was opened and nothing is quoted from it. The book itself is in print and not digitised in any open collection; where CiderHQ needs a figure from this territory it uses an accessible research source instead and says so.
Cider and perry production technical training material
Peter Mitchell / Cider and Perry Academy · reference work · registered as competent for this subject
Searched again on 2026-08-25 and it remains the one printed source here that a bibliographic check cannot fix, because it is not a published work with an edition. It is course material issued to participants of a training programme, so there is no catalogue record to verify, no ISBN, and no lawful public copy. Its state stays `registered` for that reason rather than through inattention.
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.
Vinetum Britannicum, or a Treatise of Cider
John Worlidge · historical source · passage verified 2026-08-24 · covers 1676
Identified on 2026-08-24 from the 1678 edition held by the Internet Archive. John Worlidge, active 1669–1698; the work ran to further editions including 1691, so a citation to it should say which. The full title is broader than the short one CiderHQ uses and matters for what the book can be cited for: it covers other fruit wines and drinks alongside cider, so it is evidence about seventeenth-century English fruit fermentation generally rather than about cider alone.