Is wine a good investment? It is certainly an unusual one, some would suggest a risky one, and no doubt for many would prove an impossible one to avoid cashing in - in the imbibing sense - before its full monetary potential could be realised.

On a recent visit to Dublin, wine expert and author Jancis Robinson told The Irish Times: "I don't want to manage my cellar, I want to drink it." Her view that wine is something to be enjoyed and savoured, rather than be treated as a commodity is shared by most ordinary drinkers and interestingly, by most wine merchants who rarely keep stocks of rare and expensive wines in their cellars.

Yet buying wine for investment purposes is not as incongruous as it sounds. The purchase of fine wines - mainly first and second growth vintages from the most famous French chateaux and vineyards is widespread among the very rich who, it must be said, do tend to drink these wines.

The market in fine wines - that is, the putting down and eventual re-sale - is less commonplace. Leading wine merchants here - such as Findlater, Mitchell and O'Brien's - keep stocks of young fine wines and order cases specially for a select group of collector/drinkers. But keeping large numbers of old wines in their cellars with the view to selling them on 20 or 30 or 50 years later at hugely inflated prices simply does not happen.

"The first point is that if you want to buy fully mature fine wines it is very hard to find them," says Mr Keith McCarthy Morrough, managing director of Findlater Wine Merchants.

"A case of 1996 Mouton Rothschild first growth - which won't actually be shipped until autumn '98 - costs £800 to £1,000 a case, if you can get it. This wine will probably be first drunk in 2010 and keep drinking for another 25 years or so, so you can see the sort of investment in time and money that is involved in laying down such stock."

Good wine merchants will have stocks of `92, `93 and `94 1992, 1993 and 1994 fine wines on their premises and even some small quantities of `86-`88 1986 - 1988 vintages but, says Mr McCarthy Morrough, "these would even have made the round of the trade".

For Findlater's 50 or so private clients who do want regular stocks of the finest vintages, the orders are placed early - and competition is fierce for what are very small amounts of product.

The most famous vineyards produce what is literally a drop of wine in the ocean of ordinary, but drinkable sauvignons: Chateau Mouton produces just 25,000 cases of its famous first growth wine, whereas its region, Bordeaux produces 7-8 seven-to-eight million cases. The even rarer Chateau Petrus produces just 20,000 cases in a good year.

"A single bottle of 1982 Mouton sells for up to £600 today," he says. A case is worth much more than 12 times that amount.

"These great vintages represent less than 1 per cent of all the wine produced each year and the biggest single buyers are from the Far East, who frankly, have distorted the market," says Mr McCarthy Morrough. If you have the patience not to drink your investment and can get access to the grand cru classe wines, there is no question that great wine can be a great investment. At the very least, your investment should rise by a compound interest rate of 6 per cent, says Mr McCarthy Morrough. Realising your asset is another matter. Capital Gains Tax is payable on the profits of most investments, but it has been suggested that wine may come under a lesser known Revenue classification known as a "wasting chattel" or "wasting asset".

Such an asset - so long as its lifespan does not exceed 50 years - is not subject to CGT like other assets such as property, stocks and shares or fine art. A spokeswoman for the Revenue Commissioners said "there has never been an application for wine to be classified as a wasting chattel for CGT purposes," but admitted that the British revenue authorities do allow whiskey into this category.

Finally, unless you have a dark, cool spot under the stairs where the temperature remains constant, wine investors are probably better off leaving their cases in their wine merchant's cellars.

Findlater has the largest cellars - 45,000 sq ft - at its Harcourt Street vaults. A few years ago it put together a special wine-laying service in which cases can be kept under ideal conditions for £5 a case per year.