What is Vodka?

Vodka is the dominant spirit of Eastern Europe. It is made by fermenting and then distilling the simple sugars from a mash of pale grain or vegetal matter. Vodka is produced from grain, potatoes, molasses, beets, and a variety of other plants. Rye and wheat are the classic grains for Vodka, with most of the best Russian Vodkas being made from wheat while in Poland they are mostly made from a rye mash. Swedish and Baltic distillers are partial to wheat mashes. Potatoes are looked down on by Russian distillers, but are held in high esteem by some of their Polish counterparts. Molasses, a sticky, sweet residue from sugar production, is widely used for inexpensive, mass-produced brands of Vodka. American distillers use the full range of base ingredients.
Distillation of VodkaThe choice of pot or column still has a fundamental effect on the final character of Vodka. All Vodka comes out of the still as a clear, colorless spirit, but Vodka from a pot still (the same sort used for Cognac and Scotch whisky) will contain some of the delicate aromatics, congeners, and flavor elements of the crop from which it was produced. Pot stills are relatively "inefficient," and the resulting spirit from the first distillation is usually redistilled (rectified) to increase the proof of the spirit. Vodka from a more "efficient" column still is usually a neutral, characterless spirit.
Except for a few minor styles, Vodka is not put in wooden casks or aged for an extensive period of time. It can, however, be flavored or colored with a wide variety of fruits, herbs, and spices.

Source: Tastings.com