A guest holds up a glass of Prosecco and a glass of Champagne and asks, quite reasonably, why one costs four times the other when "they are both fizzy white wine." You have about fifteen seconds. The honest answer is that the bubbles were put there in two entirely different ways, and the method changes everything.
The one thing all sparkling wine has in common
Every sparkling wine starts as a still base wine — deliberately picked early, so it is high in acid and low in alcohol. On its own it would be thin and sharp. The bubbles come from a second fermentation: add sugar and yeast to that base wine, trap it in a sealed vessel, and the carbon dioxide the yeast produces has nowhere to go but into the wine.
The only real question is: sealed in a bottle, or sealed in a tank?
Traditional method (méthode traditionnelle)
The second fermentation happens inside the bottle the wine is sold in.
- Base wines are blended (the assemblage).
- Sugar and yeast (liqueur de tirage) are added; the bottle is sealed.
- Second fermentation happens in bottle. The dead yeast (lees) stays in contact with the wine — this is the crucial step.
- Ageing on the lees, from months to many years, develops bread, biscuit, brioche and toast flavours through autolysis.
- The lees are worked into the neck (riddling) and removed (disgorgement).
- A dose of wine and sugar (dosage) tops it up and sets the final sweetness.
Result: fine, persistent bubbles, high acidity, and pronounced autolytic complexity. Expensive, because it is slow and hand-intensive.
Tank method (Charmat / metodo Martinotti)
The second fermentation happens in a large pressurised steel tank, then the wine is filtered and bottled under pressure.
Result: fast, cheap, and it preserves the fresh primary fruit and floral character of the grape. There is little or no lees contact, so no biscuit or brioche. That is not a failing — it is the entire point. Prosecco is supposed to taste of pear and white flowers, not toast.
| Traditional method | Tank method | |
|---|---|---|
| Second fermentation | In bottle | In tank |
| Lees ageing | Long — the source of complexity | Little or none |
| Flavour | Biscuit, brioche, toast, nuts | Fresh pear, apple, floral, primary |
| Bubble | Fine, persistent | Softer, frothier, less durable |
| Cost | High | Low |
| Examples | Champagne, Cava, Franciacorta, English sparkling | Prosecco, most Sekt, Asti |
Other routes worth knowing
- Carbonation — CO2 is simply pumped in. Cheapest of all; large, short-lived bubbles.
- Asti — a single fermentation stopped early, keeping natural grape sugar and low alcohol. Sweet, grapey, deliberately simple.
Onboard Notes
- If a guest wants "toasty, complex, serious," they want traditional method. If they want "fresh and easy for the pool," tank method is the better wine, not the lesser one.
- Never chill sparkling wine in the freezer and never shake a bottle you are about to open. Both are how people get hurt.
- The pressure in a traditional-method bottle is roughly three times that of a car tyre. Treat every cork as a projectile until it is safely in your hand.