Do you fancy some "long, lingering contentment" or a bagful of "raspberry ruffles"?

Would you like to sniff deeply in a "lady's handbag - soft leather, fag packets, sherbet lemons and perfume" … or taste "foamy shrimps, cigar and charcoal smokiness"? Welcome to the totally bonkers and occasionally brilliant world of the Scotch Malt Whisky Society which has just turned 30.

The florid tasting notes above come from its bottling list for November, offering members the chance to snap up a bottle or two of something unique. The society has only ever dealt in undiluted single cask whiskies, bottled with two numbers - one for the distillery and the other for the cask.

Guessing the distillery is part of the fun, but it only gets you so far because of the variation in individual casks. I never quite believed this until tasting whisky at Lochnagar on Deeside, from two barrels filled on the same day that had lain side by side for 15 years. They were remarkably different, yet normally such differences are dissolved in a giant blending vat to create the house style of each distillery.

To the amazement of its founders, the society has ballooned into a global force with more than 25,000 members, and offshoots and partner bars from Glasgow's Bon Accord to Indigo in Mumbai. It all began one evening in Edinburgh in the late 1970s. Paul Miles, the present MD, says: "A group of friends were having dinner and someone produced a bottle of whisky that was unlabelled. It contained bits of carbon and turned cloudy when water was added, but everyone loved it."

At the time single malt whisky was a very new vice and restricted to a handful of brands like Glenfiddich and Macallan, while single cask whisky was virtually unheard of. The man who produced the bottle, the whisky writer Pip Hills, was persuaded to go back to the source - Glenfarclas on Strathspey - and purchase a whole cask for everyone to share.

Within a few years this expanding group had burst out of its Edinburgh townhouse, so it was decided to form a club which anyone could join, and buy the Vaults in Leith whose 15th-century wine cellars had been used by the monks of Holyrood Abbey. The founders simply wanted somewhere "to store casks and do samplings of those they intended to bottle," says Miles.

Word spread among the members that if you pitched up on a Friday or Saturday, you would be given a tour and a free dram. There was no charge because they didn't have a licence, until they did the obvious thing of creating a members' room. With its log fire, comfy leather sofas and some 200 unique bottles to choose from, it became a heaven on earth for whisky lovers.

Having established a branch in London, the society may have overstretched itself trying to buy a third venue in Queen Street, in the heart of Edinburgh's New Town. Either way, Glenmorangie stepped in to buy the society in 2004, which caused some concern among members. Today, though, being corporately owned doesn't seem to have really changed things, and Miles insists the society remains completely non-partisan. For details on how to join, visit smws.co.uk.