“Méthode Champenoise” Champagne Bottling Equipment

More about the process of making Champagne

Champagnisation is the long-awaited moment when all the skills and savoir-faire of the winemaker come into their own. Still wine produced by alcoholic fermentation is about to become effervescent —an all-important process that is specific to the Méthode Champenoise. This is the name given to that combination of age-old skills and minute attention to detail that so perfectly captures the Champagne region and its namesake beverage.

The French term tirage refers to drawing off the blended wines into bottles ready for a second alcoholic fermentation. Called the prise de mousse (literally ’capturing the froth’), this is the stage when the wine starts to bubble as a result of the carbon dioxide given off in the process. To kick-start second fermentation, the winemaker prepares a liqueur de tirage — still Champagne (vins clairs) mixed with a small quantity of sugar (see below) and liquid cultures of active wine yeast strains (ferments de tirage).

It should be noted that before Louis Pasteur’s revolutionary discovery, the addition of the liqueur de tirage was a rather ad hoc process that invariably resulted in broken bottles (up to 80% in 1828). This was not helped by the fact that glass at the time was hand-blown and bottles varied widely in quality. It was not until the early 19th Century that advances in bottle technology removed much of the uncertainty from second fermentation.

These days the addition of the liqueur de tirage is precisely calculated to produce an increase in pressure of 6 kg/cm2 by the end of fermentation. This corresponds to 24 grams of sugar per litre of blended wine, using a liqueur de tirage containing 500-625 grams of sugar (rock candy) per litre.

At one time, there used to be a lightly sparkling version of Champagne, "Champagne Crémant", which contained half this amount of sugar (12 grams instead of 24 grams), with half the amount of pressure as a result.

The liquid yeast cultures in the liqueur de tirage must include one of the three strains of Saccharomyces cerevisiae used in primary alcoholic fermentation — specially selected strains of dry yeast, with particular organoleptic qualities plus the ability to trigger the prise de mousse.

The yeasts are brought back to life in a mixture of still wine, water, sugar and diammonium phosphate. The wine serves to feed the yeast while the water, present in very small quantities, prevents the alcohol level from exceeding 11°-12°. The sugar meanwhile provides a source of carbon and fermentable matter, and the diammonium phosphate provides the nitrates necessary for cell growth.

The production of these yeast cultures lies at the heart of the "Champagnisation" process. In those rare cases where they fall short of the mark, secondary fermentation is ineffective and the wine must be returned to the vat — what French winemakers call a remise en cercles or "return to hoops" (a reference to the hoops around a wooden barrel).

To encourage yeast activity, the winemaker uses state-of-the art technology: fermenting bins, equipped with powerful mixing paddles, temperature control and oxygen injection systems.

Yeast multiplication and conditioning — the stage in the course of which the yeast adapts to the environment of secondary fermentation — can take anything from four days to several weeks. The culture obtained contains some 40-80 million live yeast cells per millilitre of liquid. It is added at the bottling stage at a concentration of 3 litres liqueur per hectolitre of wine, producng an inoculation rate of 1.2-2.4 million live yeast cells per litre of wine.

Ten years ago yeast was simply considered a fermentation agent. Today, science has shown that yeast contains a world of possibilities: each different strain produces a range of flavours and aromas all of its own.

Riddling aids are also added just before bottling: natural and/or mineral adjuvants (tanins, bentonite, alginates) that help the dead yeast cells (lees) to clump, so they don’t stick to the sides of the bottle. The heavier the deposit, the more easily it slides into the bottle neck.

The last stage before final bottling is to mix everything thoroughly in a tank — the blended wine, the liqueur de tirage containing the yeast culture and the riddling aids.

At the end of this process, the wine is bottled. Once filled, a standard Champagne bottle is sealed with a bidule: a hollow plastic cylinder designed to hold the residue of yeast that collects in the course of riddling. Held in place by a metal crown cap, the bidule, like its natural cork predecessor, prevents loss of pressure while still allowing for that slow, controlled oxidation so essential to the success of second fermentation.

By law, Champagne wines may not be bottled until the January following the harvest. Bottling can take anything from a few days to eight months depending on the size of House and the bottling facilities available.

• Text source: Maisons Champagne
• Educational videos on the production of champagne