Craigduff is the experimental peated malt from the Glen Keith distillery. This particular whisky was aged for a staggering 40 years in a refill sherry butt (cask no. 2516). Coincidentally (or was it?), it was distilled on the 4th of April, 1973, and bottled on the exact same date in 2013, with an outturn of 616 bottles, all at glorious, natural cask strength. The chaps at Signatory vintage has bottled a truly interesting single malt.