Scotch whisky whisky used. An age statement on the bottle, in the form of a number, must reflect the age of the youngest whisky used to produce that product. A whisky with an age statement is known as guaranteed age whisky. Scotch whisky without an age statement may, by law, be as young as three years old. In the early 21st century, such "No age statement" whiskies became more common, as distilleries responded to the depletion of aged stocks caused by improved sales. Labels may also carry various declarations of filtration techniques or final maturation processes. A Scotch whisky labelled as "natural"
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