From Vine to wine
Deep inside the cellars, the bottles embark on a long period of maturation – a key phase in Champagne making in which the cellar play a critical role by keeping the wines at a relatively constant temperature of 12°C (54°F).
The lees mainly consist of yeasts that have multiplied in the bottle and formed a deposit. By the end of second fermentation, all of the sugars have been consumed and the yeasts gradually die and decompose. This process is known as autolysis, releasing molecules that are slowly transformed as they interact with those in the wine.
The special tirage stopper meanwhile allows minute quantities of oxygen to enter the bottle and small amounts of carbon dioxide to escape - in other words, the seal is not perfectly airtight. The choice of stopper is critical in determining the speed of the Champagne’s development.
Maturation on lees therefore involves two processes that occur simultaneously:
These processes complement each other especially well in Champagne, due to the delicate structure of the wines themselves. Maturation on lees is essential to encourage the gradual development of the so-called ‘tertiary aromas’ associated with graceful aging
Maturation on lees is a continuous process. The greatest Champagne wines can spend several decades maturing in the Champagne cellars.
All Champagne wines must spend at least 15 months in the bottle before release, of which 12 months maturation on lees is required for non-vintage cuvees. The minimum for vintage cuvees is three years. In practice, most Champagne wines are cellared for much longer: 2-3 years for non-vintage wines and 4-10 years for vintage Champagne.
The minimum aging periods required by law for Champagne wines are much longer than for any other sparklings. European wine regulations specify a minimum of just 90 days for effervescent wines in general.