Section 4 · Sparkling Wines

Sparkling Wine Production

Sparkling wine is still wine with bubbles, but how those bubbles get there, and what happens along the way, is what separates a simple fizz from a complex, age-worthy Champagne. This chapter covers the production methods in detail (the textbook counts six: traditional, transfer, ancestral, tank, Asti and carbonation), because the method used is the single biggest factor determining the style of the finished wine.

Aroma kit focus: green apple, lemon, brioche, toast, biscuit, yeast, honey, cream

How Sparkling Wine Gets Its Bubbles

All sparkling wine starts as a still base wine. The bubbles come from carbon dioxide (CO₂) dissolved in the wine under pressure. When you open the bottle, the pressure drops and the CO₂ escapes as bubbles.

The key question is: where does the fermentation that makes the bubbles take place? The textbook describes six methods, and each produces a different style of wine. Three of them (traditional, tank and transfer) carry most of the world’s sparkling wine; the Asti method, the ancestral method and carbonation make up the rest. Inside the EU the law often dictates which method a named wine must use; outside it, the choice is about style and cost.

The Six Methods at a Glance

Traditional Method

Second fermentation in the bottle. Extended lees ageing. Complex, biscuity, toasty. Used for Champagne, Cava, Crémant, Franciacorta, Cap Classique.

Tank Method (Charmat)

Second fermentation in a pressurised tank. Preserves fresh, primary fruit aromas. Used for Prosecco, Asti, Sekt.

Transfer Method

Second fermentation in the bottle, then transferred to tank for filtering. A hybrid, some lees character but more efficient than full traditional method.

Ancestral Method

A single fermentation, bottled part-way through so it finishes in the bottle. Often cloudy, dry to off-dry, low to medium alcohol. The “pét-nat” style.

Asti Method

A single fermentation in a pressurised tank, stopped early by chilling. Sweet, grapey, low alcohol. Used for Asti and Moscato d’Asti.

Carbonation

CO₂ is injected into a finished still wine, which is then bottled under pressure. The simplest and cheapest route, often used for aromatic varieties.

The Base Wine

Every sparkling wine starts with a base wine, and the quality of this base wine is critical. The requirements for a good sparkling base wine are specific:

High acidity: essential. The second fermentation adds CO₂ and increases the perception of acidity. If the base wine already has low acidity, the sparkling wine will taste flabby and dull. This is why sparkling wine grapes are harvested early, at low sugar levels.
Low alcohol: the base wine is typically 10–11% ABV. The second fermentation will add about another 1.2–1.3%, bringing the final wine to around 12%.
Ripe flavour with no green notes: the grapes need to be low in sugar and high in acid yet still taste ripe, with none of the unripe, herbaceous flavours of underripe fruit. Highly aromatic base wines are generally not ideal for traditional-method sparkling (except for Muscat-based wines like Asti). The complexity should come from the production process, not from overpowering fruit character.

The cool-climate dilemma: this is why sparkling wine comes from cool regions. In a warm climate, sugar rises and acidity drops so fast that the grapes are too ripe for sparkling wine before their flavours have developed. Cool regions let the grapes hang long enough to lose the green flavours while keeping acid and modest sugar.

Handling the Grapes

Hand-picking keeps bunches whole for the gentlest pressing; it is the norm for premium wines and compulsory in Champagne. Machine harvesting is common for inexpensive wines from warm regions.
Gentle pressing keeps bitter and coloured compounds out of the juice. EU rules cap both the pressure and the volume of juice that may be taken from a given weight of grapes.
Base fermentation is mostly in stainless steel, though some producers use oak for a share of the blend. Malolactic conversion and oak are both optional choices that shape the house style.

Assemblage (Blending)

For many sparkling wines, especially non-vintage (NV) Champagne, blending is one of the most important steps. The winemaker blends:

Different grape varieties: Chardonnay for citrus, finesse and longevity, Pinot Noir for body and structure, Pinot Meunier for fruitiness and roundness
Different vineyards: many small parcels fermented separately, to achieve consistency and complexity
Different vintages (reserve wines), wine held back from previous years, blended in to maintain a consistent house style year after year and to add the dried-fruit complexity of older wine. This is why NV Champagne can taste remarkably similar from release to release.
Different treatments: oak-aged components, or wines that did or did not go through malolactic conversion, each add a layer

Why pressing matters: For sparkling wines made from red grapes (like Pinot Noir), the grapes must be pressed quickly and gently to avoid extracting colour from the skins. The juice runs off clear. This is why you can make a white sparkling wine (Blanc de Noirs) from 100% red grapes, the colour is in the skins, and careful pressing keeps the juice pale.

The Traditional Method (Méthode Traditionnelle)

Also known as méthode champenoise (méthode traditionnelle) (though legally, only Champagne can use that term). This is the most complex, labour-intensive, and expensive method, and it produces the most complex sparkling wines.

Step-by-Step Process

1. Base Wine Production

Grapes are harvested early (high acid, low sugar) and fermented into a dry still wine. Each variety and vineyard parcel is typically fermented separately.

2. Assemblage (Blending)

The winemaker blends base wines from different varieties, vineyards, and vintages to create the desired style. For vintage Champagne, all grapes come from a single year. For NV, reserve wines from previous years are blended in.

3. Liqueur de Tirage

A mixture of sugar, yeast, yeast nutrients and a clarifying agent (to help the lees settle later) is added to the blended base wine just before bottling. This is the fuel for the second fermentation. The wine is then bottled and sealed with a crown cap (like a beer cap) fitted with a small plastic insert that will collect the sediment.

4. Second Fermentation in Bottle

The yeast consumes the added sugar, producing alcohol and, critically, CO₂. Because the bottle is sealed, the CO₂ cannot escape and dissolves into the wine under pressure (typically 5–6 atmospheres). This creates the fine, persistent bubbles that characterise traditional-method sparkling wines.

5. Lees Ageing (Autolysis)

After the second fermentation is complete, the dead yeast cells (lees) remain in the bottle. Over time, these cells break down, a process called autolysis. This is the magic step that distinguishes traditional-method wines from all others.

What autolysis does to the wine:

Adds biscuit, bread dough, brioche, and toast aromas and flavours
Creates a creamy, rich mouthfeel
Produces finer, more persistent bubbles (the mousse)
Increases complexity and depth

Time matters: The longer the wine ages on lees, the more pronounced these characteristics become. Autolysis is most active in the first four to five years, though it can carry on longer, and keeping the wine on its lees also protects its freshness. Most wines are disgorged before autolysis has fully run its course. Minimum ageing requirements:

NV Champagne: at least 15 months from bottling (tirage) to release, of which at least 12 months must be on the lees (most quality houses do 2–3 years or more)
Vintage Champagne: at least 36 months from tirage to release, again with at least 12 months on the lees (top examples: 5–10+ years)
Cava: minimum 9 months on the lees (the textbook figure). Under the DO Cava rules in force since 2022, Reserva needs 18 months and Gran Reserva 30 months
Crémant: minimum 9 months, as do Saumur and Vouvray sparkling wines
Cap Classique (South Africa): minimum 12 months

6. Riddling (Remuage)

After lees ageing, the dead yeast must be removed. First, the bottles are gradually tilted from horizontal to upside-down, and gently rotated, so that the lees slide down into the neck of the bottle. Traditionally this was done by hand on an A-frame rack called a pupitre, a skilled remueur could handle 40,000 bottles per day, turning each one by a quarter-turn. Today, most producers use automated gyropalettes (metal cages that rotate hundreds of bottles at once), which do the job in a matter of days instead of up to about 8 weeks by hand.

7. Disgorgement (Dégorgement)

The neck of the inverted bottle is dipped into a freezing solution (−25°C), which forms an ice plug trapping the lees. The crown cap is removed, and the pressure inside the bottle shoots out the ice plug and the lees. The whole thing takes seconds, which limits the loss of pressure and the exposure to oxygen. The wine is now clear.

8. Dosage

After disgorgement, a small amount of wine (sometimes mixed with sugar) called the liqueur d'expédition is added to top up the bottle and set the final sweetness level. The amount of sugar added determines whether the wine is Brut Nature, Extra Brut, Brut, and so on. Brut Nature (also called zéro dosage) means no sugar is added at all. The liqueur is also a second blending step: the producer can choose a young wine, an oak-aged wine or an older reserve to fine-tune the style. A cork and wire cage (muselet) are then fitted; the familiar mushroom shape comes from a straight cork being compressed into the neck. The wine then usually rests for a few months before release. Because the age of a non-vintage wine is otherwise unknowable, some producers print the disgorgement date on the label.

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Exam Angle

The traditional method is heavily tested. You must be able to explain the full process, but especially these key points: (1) second fermentation happens in the same bottle that reaches the consumer; (2) autolysis during lees ageing creates the distinctive biscuit/brioche character; (3) the dosage determines sweetness level.

The Tank Method (Charmat / Martinotti)

Named after Eugène Charmat (France) and Federico Martinotti (Italy), this method conducts the second fermentation in a large, sealed, pressurised stainless steel tank rather than in individual bottles.

How It Works

The base wine is transferred to a pressurised tank
Sugar and yeast are added
The second fermentation takes place in the tank (producing CO₂ under pressure, just like in a bottle)
After fermentation, the wine is filtered and bottled under pressure

Why the Style Is Different

The tank method produces sparkling wine with a fundamentally different character from the traditional method:

Preserves primary fruit aromas: because there is minimal lees contact and little autolysis, the fresh, fruity, floral character of the base grape is preserved. The base wine typically sees no malolactic conversion and no oak. This is exactly what you want for Prosecco (Glera grape).
Little biscuit/brioche character: those autolytic notes develop with extended lees ageing. Some producers stir the lees in the tank with paddles to pick up a little of that character
Lighter, frothier mousse: the bubbles tend to be larger and less persistent than traditional-method wines
Faster and cheaper: the entire process can be completed in weeks rather than months or years. It is the cheapest of all the methods, and although it is often seen as the lesser one, good quality is perfectly possible
Lower pressure: some tank-method wines (e.g., Prosecco Frizzante) are bottled at lower pressure (2.5–3 atm vs 5–6 atm for traditional method), giving a gentler fizz

Tank method is not inferior, it's different. Prosecco is supposed to taste of fresh pear, apple, and white flowers, not biscuit and toast. The tank method is the right method for that style. The exam wants you to understand that each method produces the style it's designed for.

The Transfer Method

A hybrid between the traditional and tank methods. The second fermentation happens in the bottle (like the traditional method), but instead of riddling and disgorgement, the bottles are opened under pressure and their contents are emptied into a pressurised tank, where the wine is filtered to remove the lees, then re-bottled.

This gives some of the benefits of lees ageing (more complexity than tank method) without the labour-intensive riddling and disgorgement process. The liqueur d'expédition is added in the tank before the wine is re-bottled. It's used for some mid-range sparkling wines, particularly in Australia and New Zealand. The label clue: "bottle fermented" (which is technically true) rather than "traditional method" (because the wine was not disgorged from the same bottle).

The Ancestral Method

The oldest way of making sparkling wine, and the one behind today’s pétillant naturel or “pét-nat”. There is only one fermentation. The wine is bottled part-way through it, and the fermentation finishes in the bottle, trapping the CO₂. The wine may or may not be disgorged; if it is not, it stays cloudy. The results are dry to off-dry, low to medium in alcohol, and the pressure varies from bottle to bottle.

The Asti Method

A special variant used for Asti DOCG and Moscato d'Asti DOCG. Unlike all other sparkling wines, these undergo only one fermentation: there is no separate base wine step.

Fresh Muscat grape juice is stored cold and unfermented, then transferred to a pressurised tank when needed. Fermentation begins in the sealed tank, producing alcohol and CO₂ simultaneously. When the desired sweetness and pressure level is reached, the tank is chilled to stop fermentation (yeast can't work at very low temperatures). The wine is then filtered and bottled.

Result: A sweet, grapey, low-alcohol sparkling wine (Asti sits at about 7% abv, at around 4–5 atmospheres of pressure; Moscato d'Asti lower still, around 5.5–7%) with intense Muscat aromas (orange blossom, grape, peach) and no autolytic character, made to be drunk young. Moscato d'Asti is only slightly fizzy (frizzante), while Asti is fully sparkling (spumante).

Carbonation

The simplest method of all. CO₂ is injected into a finished still wine, which is then bottled under pressure, the same way a soft drink is made. There is no second fermentation and no autolysis, so the wine tastes exactly like the base wine with bubbles. That makes it a sensible choice for aromatic varieties whose primary fruit is the whole point, and for inexpensive wines.

Styles of Sparkling Wine

Non-vintage (NV): a blend across years, built around a house style with reserve wines.
Vintage: in Champagne, 100% from a single year. Some other appellations allow a small share of other years.
Rosé: by blending in red wine or by a short maceration (see below). The colour can be adjusted at the dosage stage with the liqueur d'expédition, though some appellations only allow the maceration route.
Blanc de Blancs: white grapes only (Chardonnay in Champagne). Lean and citrussy when young, with the acidity to age for a long time.
Blanc de Noirs: black grapes only, pressed quickly to keep the juice white. Fuller-bodied, and ready sooner.
Prestige Cuvée: a house’s top wine, from its best grapes and parcels, usually with long lees ageing.

Sweetness Levels in Sparkling Wine

The sweetness of a sparkling wine is determined by the dosage (for traditional method) or by stopping fermentation at the desired sugar level (for tank method). The EU defines these terms on the label:

Sparkling Wine Sweetness Terms

Brut Nature / Zero Dosage

0–3 g/L sugar. Bone dry. No sugar added after disgorgement.

Extra Brut

0–6 g/L. Very dry.

Brut

0–12 g/L. Dry. The most common style by far. Most Champagne and quality sparkling wine is Brut.

Extra Dry / Extra Sec

12–17 g/L. Confusingly named, this is actually off-dry, not extra dry. Common for Prosecco.

Sec / Dry

17–32 g/L. Medium sweet.

Demi-Sec

32–50 g/L. Sweet. Often paired with desserts.

Doux

50+ g/L. Very sweet. Rare.

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Exam Trap

"Extra Dry" does NOT mean very dry. It actually means off-dry (12–17 g/L sugar). This is one of the most counterintuitive terms in wine, and it comes up on the exam. Most Prosecco is labelled Extra Dry (slightly sweet) or Brut (dry).

Exam note: the specification only requires you to know three of these terms and their sugar bands: Brut Nature, Brut and Demi-Sec. The rest of the table is context, not a memorising job.

Rosé Sparkling Wine

There are two ways to make rosé sparkling wine:

Blending: adding a small amount of still red wine (usually Pinot Noir) to the white base wine before the second fermentation. This is the most common method in Champagne and is one of the only cases where blending red and white wine to make rosé is legally permitted.
Saignée / maceration: brief skin contact with red grapes to extract a pink colour before pressing. Used by some producers for a more intense, berry-fruited style.

Method vs Style: Side by Side

Factor	Traditional Method	Tank Method
2nd fermentation	In bottle	In pressurised tank
Lees ageing	Months to years (autolysis)	Minimal or none
Aroma character	Biscuit, brioche, toast, cream, yeast (secondary/tertiary)	Fresh fruit, flowers, citrus (primary)
Mousse quality	Fine, persistent, creamy bubbles	Larger, frothier, less persistent
Complexity	High, layers of flavour	Lower, simple, refreshing
Cost	High (labour, time, storage)	Lower (faster, more efficient)
Key examples	Champagne, Cava, Crémant, Franciacorta	Prosecco, Asti, Sekt

Aroma Kit Integration

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Sparkling Wine Aroma Session (20 min)

Pull these from your kit: green apple, lemon, brioche/bread, toast, biscuit, honey, cream. Smell them individually. The first two are primary fruit aromas (base wine). The rest are autolytic aromas (from lees ageing). Can you spot which aromas you'd expect in Prosecco (apple, lemon, pear, primary) vs Champagne (brioche, toast, biscuit, autolytic)?

Wine drill: Taste a Prosecco alongside an NV Champagne. Same category (sparkling), entirely different production method and style. Focus on the mousse (bubble size and persistence), the aroma profile (fruity vs biscuity), and the finish length.

What the Exam Expects You to Know

The traditional method, every step from base wine to dosage, and why each step matters
What autolysis is and how it affects flavour, texture, and mousse quality
The tank method, how it works and why it produces a different style
The six methods by name: traditional, transfer, ancestral, tank, Asti, carbonation
Which method is used for which wines (Champagne = traditional; Prosecco = tank; Cava = traditional)
Sweetness level terms, especially the "Extra Dry" trap
How rosé sparkling wine is made (blending vs saignée)
The role of assemblage and reserve wines in creating consistent NV Champagne

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Short Answer Strategy

If asked to explain how the traditional method creates its distinctive character, build your answer around: second fermentation in bottle → CO₂ dissolves under pressure (fine mousse) → extended lees contact → autolysis releases compounds (biscuit, brioche, cream) → dosage sets final sweetness → result is complex, layered sparkling wine.

Active Recall Prompts

Close this page and try to answer these from memory:

What is the liqueur de tirage and what does it do?
What is autolysis? Name three flavours it creates.
What are the minimum ageing rules for NV Champagne? For vintage Champagne? How much of that must be on the lees?
Name the six sparkling wine methods in the textbook.
Why does the tank method preserve primary fruit aromas?
What is the difference between riddling and disgorgement?
What sweetness level does "Extra Dry" actually indicate?
Name two methods for making rosé sparkling wine.
Why is Prosecco made by the tank method rather than the traditional method?
What is the role of reserve wines in NV Champagne?