Vodka is a neutral spirit distilled from fermented materials like corn, wheat or rye. It originated in Russia in the 17th century and spread to other parts of Northern and Eastern Europe. Vodka is distilled at over 95% alcohol by volume, then filtered and diluted with water before bottling. Flavored vodkas are also produced, such as Zubrowka flavored with bison grass, Starka aged in oak casks, and Pertsovka infused with peppers. Major brands of vodka include Smirnoff, Nikolai, and Stolichnaya.