vin doux naturel, translates directly from French as a wine that is naturally sweet but is a term used to describe a French wine speciality that might well be considered unnaturally sweet. Nature’s sweetest wines contain so much grape sugar that the yeasts eventually give up the fermentation process of converting sugar into alcohol, leaving a residue of natural sugars in a stable wine of normal alcoholic strength (see sweet winemaking). Vins doux naturels, on the other hand, are made by mutage, by artificially arresting the conversion of grape sugar to alcohol by adding spirit before fermentation is complete, thereby incapacitating yeasts with alcohol and making a particularly strong, sweet half-wine in which grape flavours dominate wine flavours. They are normally made of the grape varieties muscat and grenache, and should have an alcoholic strength of between 15 and 18% and a potential alcohol of at least 21.5%. The minimum residual sugar level varies from 45 g/l for Rasteau and Banyils, to 100 g/l for the various Muscat de Somethings.