Tirage

What it is

Tirage is the stage in which the still base wine goes into the bottle together with a liqueur de tirage, the mix that triggers the second fermentation inside the bottle. It is the first essential step of the méthode champenoise after the assemblage of the base wine is complete.

What happens

In a Champagne house’s tirage hall, three components come together in every bottle:

1. Base wine (vin clair): the assembled still wine at around 10.5 percent alcohol
2. Liqueur de tirage: a mix of wine, sugar (~24 g/l) and yeast cultures plus a clarifying agent (bentonite or casein)
3. Crown cap: the temporary seal for the years of ageing to follow

The yeast starts converting sugar into alcohol and CO₂. Because the bottle is sealed and the CO₂ can’t escape, pressure builds to about six bars, comparable to a double-decker bus tyre. Alcohol rises by about 1.2 percent (to 11.7-12 percent).

When

Classically in the spring after harvest. The base wine has been through winter, settled and stabilised. For vintage Champagne: the spring after harvest (April-May in year n+1). For non-vintage: the same, but with assemblage using reserve wines from earlier vintages.

Which yeast

The yeast choice is a specialty. Two main directions:

• Saccharomyces bayanus: alcohol-tolerant, works in colder conditions, survives longer in bottle after fermentation. The default for almost all commercial Champagne.
• Saccharomyces cerevisiae: warmer and faster fermenting, but less suited to the low temperatures in Champagne cellars.

Some houses use their own selected yeast strains (Krug has kept its proprietary strain for decades). Others experiment with indigenous yeast (natural ferment) — riskier, but potentially more complex.

Tirage step by step

1. Base wine is warmed to ~13 degrees Celsius (yeast needs warmth to start)
2. Liqueur de tirage is added mechanically, often via a dosing machine
3. Mixture is filled into bottles via the bottling line
4. Crown cap on, bottle stacked horizontally in the cellar
5. Fermentation runs 4 to 8 weeks at 10-12 degrees
6. Then a minimum 12 months (non-vintage) or 36 months (vintage) on the lees — autolysis phase

Legally

The Comité Champagne mandates tirage in glass. Other sparkling wines can do tirage in tank (Charmat method for Prosecco) but that style isn’t called méthode champenoise. For the “Champagne” label, bottle tirage is mandatory.

What follows

After tirage the bottle goes horizontal in the cellar for the second fermentation (~four to eight weeks) followed by the autolysis phase. The law sets a minimum of twelve months on the lees for non-vintage, three years for vintage. In practice top producers go substantially longer (Krug ~7 years, Bollinger R.D. 10-15 years).

For the drinker

Tirage is invisible to the consumer. But knowing that tirage happens in glass (not tank) is what sets Champagne apart from Prosecco. It’s the physical bottle in which the bubble that you later see in your glass is born.