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 in wood for a similar time. After a decade or two, additional aging in a barrel does not necessarily improve a whisky. While aging in wooden casks, especially American oak and French oak casks, whisky undergoes six processes that contribute to its final flavor: extraction, evaporation, oxidation, concentration, filtration, and colouration. Extraction in particular results in whisky acquiring a number of compounds, including aldehydes and acids such as vanillin, vanillic acid, and syringaldehyde. Distillers will sometimes age their whiskey in barrels previously used to age other spirits, such as rum or sherry, to impart particular flavours. Most whiskies are sold