Dewar's The Signature 25 Year Old Blended Scotch Whisky was created by the eponymous Dewar family. Over 40 of the finest grain and single malt whiskies aged at least 25 years and older are blended together and then filled into the specially selected oak casks to begin the six month long double-aging process. In an extra step unique to the new 25-Year-Old expression, the whisky was then filled into a set of freshly disgorged Royal Brackla casks for an extra period of finishing.