All single malt whiskies from Scotland must come from the same distillery and may be a blend of such from different small-batch distilled malts which may be of varying ages until the master distiller is satisfied with its taste, character and quality.
Made only from barley, they must be aged in oak for a minimum of 3 years although most are matured for much longer, typically for ten years and more with the age statement on the label denoting the youngest whisky used. There are, give or take, because of those closing and/or re-opening, around 100 distilleries currently in operation. Each offer their own style and flavour depending on many factors. These include the size and shape of the stills, the condenser size, the type of oak cask used for ageing which may be from America or Europe and at one time, may have been used to store, for example, port, Madeira, Bourbon and other 'cask finishes'.
Scotland has six defined regions for the production of single malts and they are: Highland, Island, Islay, Speyside, Campbeltown and Lowland. Each has their own associated style based on the traditions in their region dating back many years although these boundaries exist less and less as time goes on.