 Vins Doux Naturels are " naturally sweet " wines that have been fortified with brandy to stop fermentation , leaving residual sugar to add <unk> to the wine . The majority of Languedoc sweet white wines are made with a variety of Muscat grapes . The red fortified wines of the Banyuls are made from Grenache grapes , normally have an alcohol level between 16 and 17 % and carry residual <unk> in the 8 to 12 % range . 
