In Scotland, "malt whisky" must use a 100% malted barley mash and must be distilled in a pot still, whereas grain whisky is typically distilled in a continuous column still in a manner that results in a higher percentage of alcohol by volume (ABV), but less flavorful spirit. Because of this practice, grain whisky is seldom bottled by itself in Scotland, where it is instead manufactured primarily for blending with malt whisky to create blended whiskies, which account for over 90% of all Scotch whisky sales. The comparative lightness of the clearer, more-neutral-flavored grain whisky is used to smooth out the often harsh characteristics of single malts. Occasionally well-aged grain whiskies are released as single grain whisky if made at one distillery or blended grain whisky if combining spirits from multiple distilleries. It is important to be aware that the phrase "single grain" does not refer to using a single type of grain to make the whisky – indeed, it is against the law to produce whisky in Scotland that is made from a single grain unless the grain is barley – in which case it would be considered a "malt whisky" rather than a "grain whisky". Instead, "single grain" refers to using a single distillery to make a whisky from at least two types of grain – one of which is required to be barley (From Wikipedia).