Ola Dubh 18 (pronounced ola-doo and Gaelic for black oil) is what you get when you age Old Engine Oil in casks formerly used to mature Highland Park 18 (Best Spirit in the World), which imparts a fruity, whisky character into our rich, dark beer.Ola Dubh was conceived in 2007. It was the first ale to be matured in whisky barrels from a named distillery and, with traceable casks and numbered bottles, it is a beer with real provenance. To make Ola Dubh 18, we take our Old Engine Oil (amped up to 10.5%) and age it for up to 6 months in casks that previously held Highland Park 18 Year Old single malt. And it is ready only when our head brewer, Stuart, deems it ready!Note: This beer is 8% ABV in bottle, 10.5% in cask and keg.