A Time to Live and a Time to Die. That is the title of a 1985 film directed by Hou Hsiao-Hsien, which won the 1986 Berlin International Film Festival. It also aptly applies to a bottle of wine, however fine, however expensive.

This week, I want to address the repeated question that wine lovers face - which is when to drink a bottle, especially a very precious and expensive bottle of wine. A bottle of wine from an impeccable wine-grower will live for a good many years. Assuming certain conditions are met. For example, the wine should have a certain pedigree and similarly the wine-grower, from a good vintage. Storage must also be impeccable, ie 10 degrees Celsius with 70 per cent humidity constant.

In other words, the bottle of wine must have been properly "laid down", or stored. It is not uncommon to have wines from the early 20th century still in personal cellars today.

Twenty years would not be an unreasonable lifespan for a properly made wine properly cellared, better pedigreed wines could safely be cellared up to 50 or more years. The cellars of the top Châteaux and wine estates in Europe contain bottles going back to the 19th century.

But that is not what we are addressing here. More relevant are such questions as "when is this wine ready to drink", "how long can this bottle keep".

At seven years' age, a Bordeaux or Burgundy would still be youthful but showing enough development for one to know its quality and style, and how many more years it would need to reach full maturity. (It is also a good excuse to open that bottle you have been dying to drink ever since you bought the case!) A general rule of thumb is the "seven-year" rule (not the seven-year itch!). At that age, most wines, except perhaps for the very top of the line, eg First Growth Châteaux, Romanee-Conti and the like, while still youthful, have developed sufficiently for their innate quality and intrinsic beauty to be assessed.

And if you are the DIY type, a very useful way, and very pleasant, is to take one wine, and starting at the seventh year of age, open one bottle to taste and drink to assess degree of maturity. It should then be possible to extrapolate how many more years it would need to reach sufficient maturity.

But note that when the 12th and last bottle of the case is consumed, and shows that the wine is now fully mature, the case of 12 is finished. Moral of the story: buy two, not one case of the same wine!

So a general guide would be: early maturity at seven, full maturity at 10. For higher quality wines, eg First Growths, first assessment at seven is still a reasonable age, early maturity at 10, full maturity nearer 15. It should be noted that these are only guides. And all of the above assumes we are referring to wines stored under recommended cellaring conditions.

A time to die. How long can a wine hold at its apogee? (Referring to fine wine of course, not plonk!) A further 10 generally, but a safe rule is that the higher the quality of the wine, of the vintage, and of wine-making, the longer it will hold. The life-history of the bottle since it left its cellar of birth is crucial to the quality of its contents at the time of purchase/consumption.

Should one worry? Yes and No. No in the case of inexpensive wines of current vintage for daily drinking. Yes, obviously for wines of quality.

The other perennial question? How long will this wine live? Stored under ideal conditions of course. Wines of good pedigree, and vintage, eg Bordeaux Classified Growths and Burgundies, Rhones, Italians, Spanish of equivalent rank. Some 30-40 years or more. It could outlive its owner, as has often happened.

How to tell when wines are beginning to show their age? They no longer taste fresh. Now, that is a very subjective opinion, but it does describe the impression one has when drinking a wine that is past its "sell-by" date.

As wines mature, the two tell-tale signs even before you take a mouthful are to be found in the colour and the aroma. A red wine begins to show touches of brownish tints at the edges, the body of the wine begins to show brownish hues, and the aroma of the wine does not show freshness but hints of tiredness, the after-taste lacks the limey-ness of youth in the case of white, and has lost the slightly sharp edge of the tannic finish. It is as if all qualities are blunted - smell, and taste. Soon as one of more of these are detected, if there are more bottles of the same, a mental note should be made that they should be consumed soon.

Two Burgundies tasted at dinner 10 days ago at home.

Chambolle-Musigny 1er cru Les Fuees 2002, JF Faiveley

Medium-hued garnet red, with a pale rim 2.0 mm wide. Good fresh pinot aroma, lively, delicate. Good ripeness of fruit on the palate, flavours of strawberries and pinot berries. Medium length, clean finish.

Beaune 1er cru Boucherottes 1989, Louis Jadot

Dark brownish red, almost tawny-red, much darker than the Faiveley; good characteristic pinot aroma, not as delicate on the palate as the Faiveley, rather thicker and denser. No signs of tiring.

Two burgundies, one from the Cote d'Nuits, the other from the Cote d'Beaune, one to the north, one to the south of Beaune. Both from owned vineyards.

The palate differences, a function of their different locations on the Cote d'Or, and hence different terroirs, were clearly discernible, the one (Chambolle) finer in texture, the other rather more solid. Aromas also differed not only in intensity but in character, the etherealness of the Chambolle wine in stark contrast to the more solid nature of the Beaune.

The Chambolle was much fresher than the Beaune, but the freshness of the latter relative to its 27 years' age was quite remarkable. Aroma and taste held up very well too with the Beaune. Actually, when drunk from what remained in the bottle two nights later, the Beaune was still drinking well but did show signs of fading in the glass. The Chambolle was of course much more alive and singing.

These two wines are not at "First Growths" or Grand Cru level, but they are enjoyable, they sufficiently display their grape and terroir of origin, they are more readily available than Grands Crus, and best of all they do not cost an arm and a leg!