Port is the term used to indicate the sweet fortified wine that comes from Oporto, Portugal. Only fortified wines from Oporto can use the official name "port" or "Porto." Port is made by arresting the fermentation process of wine (made from up to 80 different grape varietals) while there is still a very high level of residual sugar by adding a neutral grape brandy (fortification), which increases the alcohol level above 18%, thereby killing the yeast necessary for fermentation. The resulting port is then aged for up to two years before being placed in bottles, where it can continue aging for decades. There are seven main styles of port: ruby, tawny, vintage, colheita, crusted, late-bottled vintage, and white port.