Vodka is a typically colorless liquor, usually distilled from fermented grain or potatoes but also from other raw materials. It is thought that the term is a diminutive of the Slavic word "voda" for "water."
Except for insignificant amounts of flavorings, vodka consists of water and alcohol (ethanol). Vodka usually has an alcohol content ranging from 35% to 70% by volume. The classic Russian vodka is 40% (80 proof), the number being attributed to the famous Russian chemist Dmitri Mendeleev. According to the Vodka Museum in St. Petersburg, Russia, Mendeleev thought the perfect percentage to be 38, but since spirits in his time were taxed on their strength the percentage was rounded up to 40 to simplify the tax computation.