Cask strength, the Highs and Lows.

Scottish malts will run lower than American whiskeys at both the high and low percentages of cask strength/barrel proof. With US whiskeys the extremes I have seen are George T. Stagg @ 71.5% and, once, William Larue Weller @ 59%. Typical US: 64%, typical Scottish: maybe 57-59%. I haven't yet had the pleasure of trying the Scottish extremes.

I just bought a bottle of Aberlour A'bunadh, batch #35, which was released at 60.3% abv. That's pretty high anywhere!

Cask strength is largely a function of the original ABV, age and the "tightness" of the cask.

I recall hearing from George Grant that the 1952 cask used in the Glenfarclas 175 wasn't 40% and therefore wasn't scotch (for the purposes of individual sale). As it happens the second release of the 1952 Family Cask was cask strength and 41.9% and there are were only 55 bottles from that hogshead.

Evaporation is a bitch.

One of the suprising things about this is that it is based on the Laphroaig 10, which is at about 55% when sold at cask strength.

Oh ok, that's interesting. Just at a guess then; the bottling might be from a single cask, but isn't necessarily cask strength at bottling. I know Signatory does what appear to be single cask Laphroaig bottlings at 46%, but I don't believe these would be cask strength since it would be a rare hogshead that produced 712 bottles at cask strength.

"Cask strength" and "Single cask" are 2 different things - a whisky that's cask strength merely means that it hasn't been diluted down with water. A single cask whisky is produced in a single cask.

Single cask whiskies are often not sold at cask strength (for instance, if the bottler decides the flavour profile shows better at a lower ABV, or if they want to sell more bottles from a cask), whereas many cask strength whiskies, though still single malts, are a blend of casks (such as the above-mentioned A'bunadh).

Because each cask is different, 3 neighbouring casks laid down at the same time could evaporate at different rates, so if (hypothetically and fictionally) after 18 years one was 50%abv, one was 48%abv and one was 41%abv, you could vat them together and sell the whisky as a cask strength bottling at 46.3% abv.

The highest ABV we've had at Whisky Squad so far was for a single cask cask strength SMWS 8yo Islay bottling (127.3) at 67.3%. I have no idea what the lowest is/was, but I believe that you can't let whisky go below 40%abv to still be called "whisky".

Having said that, it's possible (and practiced) to vat old casks at 35% with perkier ones above 45% in order to get the vatting's abv to 40% and still call it cask strength. So long as the flavour's good...

Just got a bottle of Ellenstown 10.

It's a bastard malt, but most people know it to be a bottling of Ardbeg 10 at cask strength (58% abv.)