Term (also known as Pét Nat) for "naturally sparkling" wines. It is an ancient process, which is called Méthode rurale (also Méthode ancestrale) in France. There are no wine laws, so that the production can be quite different. Unlike a sparkling wine or champagne, there is no "real" bottle fermentation (initiated by the addition of yeast), but a single fermentation in two steps. After an often spontaneously initiated mash fermentation, the unfinished grape must is bottled at about 20 to g/l residual sugar and 5% vol alcohol content. However, this can be done quite differently, so that the fermentation, which continues in the bottle, can result in a weakly to strongly foaming wine. So whether a sparkling wine or a sparkling wine is produced depends solely on the time of decanting or the residual sugar still present. Whether a dégorgement (removal of the yeast) is carried out is decided by the producer, if so, no dosage and no sulphur is usually added. Such products belong to the group of Orange Wines (Natural Wines). See also under vinification.