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 three main production methods in detail, 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 second fermentation take place? There are three main methods, and each produces a fundamentally different style of wine:

The Three Main 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.

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:

Assemblage (Blending)

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

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 and yeast 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).

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. Minimum lees ageing requirements:

  • NV Champagne: minimum 15 months on lees (most quality houses do 2–3 years or more)
  • Vintage Champagne: minimum 36 months on lees (top examples: 5–10+ years)
  • Cava: minimum 9 months (Reserva: 15 months; Gran Reserva: 30 months)
  • Crémant: minimum 9 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 1–2 weeks instead of 6–8 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 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. A cork and wire cage (muselet) are then fitted.

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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

Why the Style Is Different

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

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. It's used for some mid-range sparkling wines, particularly in Australia and New Zealand. The label may say "bottle fermented" (which is technically true) but not "méthode traditionnelle" (because the wine was not disgorged from the same 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 (5.5–7% for Moscato d'Asti; 7–9.5% for Asti) sparkling wine with intense Muscat aromas (orange blossom, grape, peach). Moscato d'Asti is only slightly fizzy (frizzante), while Asti is fully sparkling (spumante).

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).

Rosé Sparkling Wine

There are two ways to make rosé sparkling wine:

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

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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: