Term for a very long aged (20 to 50 years and longer) and high quality wine, which is used in the production of champagne is used and mostly comes from a vintage. It becomes large in part magnums. stainless steel tanks or also in barrels stored. at Bollinger for example, it is stored in magnum bottles that contain a tiny amount sugar and yeasts was added to produce liveliness (pétillance = pearls). It gives the champagne the distinctive character of a house. It is or can be added at three points during production, namely at assemblage (the blend of different wines or vintages) and the two types of Dosage (Filling and shipping dosage).
Actually, a reserve wine is only supposed to be contained in vintage champagnes, but it is certain that it is added to the vintage versions by different champagne houses (according to provisions in champagne, the latter must consist of 100% of the vintage, but according to EU standards only 85%). The amount varies depending on the producer and year. With base wines of a "good" vintage, less is added accordingly. The term reserve wine is also used in the production of sherry and wines produced in a similar way also use and designate an older and high quality wine. The concept of quality has a completely different meaning reserve,