Pick a glass. Whisky A has notes of green apple, vanilla and honey. Whisky B has notes of melting plastic, spent match and tarry rope. Give this option to a whisky club, and you’d better go find another bottle of whisky B.

Everyone who appreciates a whisky enjoys the fruity esters that distillers seek to amplify, and the softening sweetness imparted by oak. However, watch a whisky lover raise their glass, describe in great detail the smell of sweaty leather or burlap sacks or birthday candles, and see their eyes truly light up. The dedicated distiller may cringe, but these weird and wacky side notes are the domain of the fanatic.

If unusual aromas and unique flavours are what you seek from a whisky, then single casks are the place to find them. Such distinctive characteristics tend to vary significantly between sister casks, much more so than the more typical, marketable flavours we associate with malt whisky. Furthermore, for a bottler, the quantities involved in a single cask make releasing whiskies that may be deemed out of character much less of a risk. It would be a brave decision for any major distillery to release a batch product of many thousands of cases of anything exhibiting flavours that some consider to be “off” notes.

In our stock evaluations at A. D. Rattray, we often note casks as “flawless”. This is a technical assessment of quality, but on its own it is maybe not the high praise it seems. Everything is there, but where is the hook? Can a whisky be too balanced? It is far more common for us to overlook casks that simply aren’t interesting enough, rather than reject them for exhibiting any peculiar notes. For us, and others who share our passion, the real beauty in single malt scotch whisky lies in the anomalies and imperfections found in a single cask.

In our selection for A. D. Rattray’s 75^th Cask Collection release, our first curation of 2025, we have considered this idea of “off” notes in whisky, what constitutes “quality”, and the value of intrigue.

Each of the five casks selected has very particular characteristics that may not be to everyone’s tastes, but are chosen to sate the appetite of the more curious among us.