The 18 year old has sat in the Bunnahabhain core range since the earlier stages of the distillery's rebuilding under Burn Stewart, when Ian MacMillan oversaw the shift to non-chill-filtered, natural colour bottlings at 46.3% across the range. That repositioning in 2010 was unusually thorough for the time and did much to rehabilitate a distillery which had spent decades as a quiet supplier of blending fillers.
The cask strength version is an occasional release rather than a permanent fixture, drawn from the same sherry-forward maturation that defines the standard 18. Where the diluted bottling is elegant and restrained, the cask strength is dense: the kind of whisky that coats the glass and rewards patience. Oloroso influence is obvious, and the spirit's underlying coastal character — the brine that all Bunnahabhain carries whether peated or not — keeps the sherry from becoming cloying.
Batches have been released at various strengths above 50%, and collectors tend to track them individually. The distillery's output has always been small relative to its neighbours, and the 18 cask strength is among the bottlings which disappear quickly from shelves. For those who find the standard 18 too polite, this is the answer: the same whisky with its coat off.
