Scotch whisky whisky" is any spirit that qualifies as a single malt Scotch whisky or as a blended Scotch whisky. The latter exclusion is to ensure that a blended Scotch whisky produced from single malt(s) and single grain(s) distilled at the same distillery does not also qualify as single grain Scotch whisky. Three types of blends are defined for Scotch whisky: The five Scotch whisky definitions are structured in such a way that the categories are mutually exclusive. The 2009 regulations changed the formal definition of blended Scotch whisky to achieve this result, but in a way that reflected traditional and current
Whisky must be aged in new charred-oak containers, except for corn whiskey which does not have to be aged. If it is aged, it must be in uncharred oak barrels or in used barrels. Corn whiskey is usually unaged and sold as a legal version of moonshine. If one of these whiskey types reaches two years aging or beyond, it is additionally designated as "straight", e.g., "straight rye whiskey". A whiskey that fulfils all above requirements but derives from less than 51% of any one specific grain can be called simply a "straight whiskey" without naming a grain. US regulations recognize