Effervescence is a naturally occurring phenomenon – fragile, complex and hard to handle. No-one understands this better than the Champagne makers themselves – cellar masters, oenologists, research centres – who now enjoy worldwide recognition as the world’s leading experts on effervescence.
The term refers to the deliberate initiation of a secondary fermentation – as opposed to the accidental second fermentation that made the wines sparkle but offered no control over the build-up of pressure. Wines produced by the Méthode Champenoise undergo primary (alcoholic) fermentation in tanks to transform the grape musts into wine. When primary fermentation is complete, all of the naturally occurring grape sugars should have been converted into alcohol. The next stage is secondary or bottle fermentation – also known as the ‘prise de mousse’ – when the wines start to effervesce.
Champagne wines have a natural tendency to sparkle because they contain macro-molecules that stabilize the bubbles thus promoting the development of the mousse. The precise nature of these macro-molecules remains to be discovered, pending the results of research by scientists at Reims university and at the Reims National Institute of Agronomic Research (INRA). One thing they do already know is that macro-molecules are destroyed by Botrytis cinerea (grey rot) and also by certain treatments used to clarify the wines.
Effervescence is not an end in itself but should complement and support the qualities of the wine. Because it accentuates the sensory characteristics of wine, effervescence is not really compatible with overly heavy, powerful or wooded aromas.
The gentle pressing technique used in Champagne avoids that problem by extracting only the juice from the flesh, with nothing from with the berry skins or stems. The aim is to balance the effervescence in young Champagne wines by a delicate bouquet of fresh and exotic fruit and floral notes.
With age, the effervescence loses some of its exuberance, becomes more cushiony, more in tune with the nutty, toasty aromas typical of old Champagne wines that have matured on their lees in the bottle. Effervescence brings the wine to life but to achieve a perfect balance of sensory characteristics, it must also support and highlight the wine’s qualities.