BOTTLING AND SECOND FERMENTATION 

Bottle fermentation transforms still wine to sparkling wine – hence the name ‘prise de mousse’, literally ‘capturing the sparkle’.

The winemaker kick-starts the effervescence by adding a sweet solution known as the ‘liqueur de tirage’ – a mixture of still wine from Champagne with cane or beet sugar (20-24 grams/litre, for a rise in pressure by the end of fermentation of up to six bars, plus selected, acclimatized yeast cultures and additives that assist the ‘remuage’ process (riddling). These consist of bentonite or bentonite-alginate that make the sediment heavier, encouraging it to slide down to the neck of the bottle, near the cork.

The rules of the Champagne appellation forbid (from half-bottle to jeroboam) the transferring of the newly effervescent wine from one bottle to another. All Champagne wines must be sold in the bottle in which they underwent their second fermentation. The bottles used must be made of strong glass, in accordance with strict specifications relating to pressure resistance and general durability. They must be capable of withstanding high pressure and repeated handling.

Once filled, the bottles are hermetically sealed with a polyethylene stopper known as a ‘bidule’, which is held in place by a crown cap. A few producers still use cork for the ‘tirage’ (bottling) stopper. The bottles are then transferred to the cellar and stacked ‘sur lattes’: horizontally, row upon row, usually in steel cages.

Inside the bottle, the wine undergoes a second fermentation that continues for 6-8 weeks. The yeasts consume the sugar, transforming it to alcohol and carbon dioxide, releasing esters and other superior alcohols that contribute to the wine’s sensory profile.