Refermentation is the process through which carbon dioxide is developed, producing the classic perlage that is visible in a glass of metodo classico sparkling wine. It is a case of in-bottle refermentation, otherwise known as secondary fermentation, which occurs while the bottle matures in the wine cellar.

The maturation period of a Trentodoc varies from a minimum of 15 months for a Brut, to 24 months for a Millesimato or even 36 months for a Riserva. This is fundamental for achieving the organoleptic complexity that every producer wants to bestow to his or her own metodo classico sparkling wine. The wine houses that produce Trentodoc sparkling wines extend maturation on the lees beyond the time indicated in the regulations and so produce a metodo classico sparkling wine of real distinction.