Last year's special release of 29-year-old Port Ellen cask strength whisky took the top prize at the San Francisco World Spirits Competition, after impressing judges with its peaty, spicy flavours.
Most bottles are pre-ordered by collectors before they make it to the shops and orders are being taken for this year's batch, to be released in September.
As the Islay distillery closed 26 years ago, and the warehouse is locked to outsiders, no-one knows how much is left.
Only 6,660 bottles were produced last year, with a recommended price of 180.
But the drink that impressed the US experts was part of a limited batch of 200 bottles, some of which have been sold on the internet for upwards of 2,000.
The Port Ellen distillery opened in 1825 and was the first in Scotland to use a spirit safe, brought in by the 1824 Excise Act to stop bootleggers siphoning off whisky without paying tax.
Owners Diageo have always refused to say how many barrels of the rare malt remain, keeping the date of the distillery's final batch a closely guarded secret.
Dr Nicholas Morgan, Diageo's Scotch knowledge and heritage director, said: "Port Ellen is, famously, a malt whisky that people avidly collect. But this award confirms that it's the seductive and masterful flavour of Port Ellen, not just its rarity, that puts it near the summit.
"These great Islay whiskies have enormous staying power."