Fortified wines are wines that have had brandy or alcohol added to them. This stops the fermentation process and results in wines that are both sweeter and stronger, typically containing around 20% alcohol by volume. There are several famous types of fortified wines including sherry, port, madeira, marsala, and malaga. Sherry is produced near Jerez, Spain using palomino grapes and follows the solera aging system. Port is produced in Douro Valley, Portugal using over 40 grape varieties and is fortified with grape spirits during fermentation. Madeira uses several grape varieties and is heated during aging, resulting in a distinctive caramel flavor. Marsala is produced in Sicily, Italy from local grape varieties