Vodka can be made from many different kinds of agricultural materials. In the EU it is usually produced from grain or molasses. In Eastern Europe it is also produced from potatoes, or rice. Neutral spirit of at least 96% alcohol by volume (ABV), having been checked that it is of the appropriate quality is either redistilled to produce a pure and flavourless spirit or filtered through activated charcoal which removes any residual impurities and odours. The definition of activated charcoal is that which has been treated either by steam or chemicals to make it more absorbent.        In many cases, the spirit is redistilled once or twice then blended with pure demineralised water, reducing its ABV to about 55% before being filtered through the charcoal. Filtration is done by either pumping the vodka through several consecutive columns of charcoal or, in the case of cheaper vodkas simply seeping it into tanks containing charcoal. Very pure water is now added to the spirit to give the legal EU minimum ABV strength of at least 37.5%; it is not unusual to have vodkas of up to 50% ABV. This pure spirit drink does not legally require anything adding to it although some producers include additives to improve the characteristics whilst others introduce flavouring by either adding natural essences or by steeping fruits or herbs in the vodka for several days. No maturation period is required for vodka.