Crémant d’Alsace is produced by a secondary alcoholic fermentation in bottle, whicih creates the effervescence in the wine. This is referred to as the “prise de mousse”.
After a period of ageing, the bottles are turned day after day on their ends, either manually or mechanically, so that the deposits may gather in the collar of the bottles while they are waiting to be disgorged.
The deposits are then brought to freezing point, thus in effect forming an “artificial cork”, which is evacuated by the pressure of carbonic gas contained in the wine.
The volume of lost fluid is then replaced by the addition of a “liqueur de dosage” which yields a Crémant d’Alsace brut, sec, or demi-sec.