A clear, mostly tasteless and odourless distilled spirit of Russian origin, vodka is the most popular liquor in the United States. Traditionally distilled from potatoes and used for medicinal purposes, modern vodka is usually made from fermented wheat, barley or rye and is often filtered prior to bottling. Due to its mild flavour, vodka has become a popular base for many mixed drinks and cocktails such as the Bloody Mary, Black Russian, screwdriver and various martinis.