The Glenmorangie distillery was one of the first to study the effects of oak on whisky. Glenmorangie stills are the highest in Scotland, with old ones replaced by new ones of exactly the same shape and size. Hard water comes from the springs of Tarlogie forests. The oak barrels used are old Kentucky bourbon barrels. Other barrels (e.g. sherry, port) are used only in the final years of the ageing process. Glenmorangie Original is Scotland's most popular single malt whisky, originating from North Highland, Tain in Ross-shire.