How to score wine

Imagine going to an art gallery and being asked to fill in a form assigning scores to each work. It does sound pretty difficult and of questionable use, does it not?

Yet the process of scoring wine, one which many of us engage in frequently, is not that far removed from assigning points to a Picasso or a De Kooning.

I would be much happier in my professional life if I were never required to assign a score to a wine. I know so well how subjective the whole business of wine appreciation is and, perhaps more importantly, how much the same wine can change from bottle to bottle and week to week, if not day to day. I frequently find myself re-tasting a wine at the same stage in its life. So far I have rarely marked more than 0.5 points out of 20 differently on the two occasions, but it wouldn't surprise me at all if I did.

And as for tasting the same wine at different stages in its life, this is even less likely to yield identical scores. Quite apart from bottle variation there are differences in tasters' moods and vast differences in how wines mature in bottle.

Even I have to admit, however, that scores have their uses. The most obvious is to help the reader-in-a-hurry – and there are a heck of a lot of us around. Don't you feel as though your life is more frenetic than it was 10 years ago? I know I do. I don't seem to have the time to linger over my newspapers and journals. Hence the advent of arts reviews which rate even plays and films with a certain number of stars – and of course the business of assigning a numerical score to wines to help potential purchasers, however much we professionals may feel our beloved liquid is too subtle to be reduced to a single number.

I find myself using all sorts of different scoring systems depending on the circumstances. When I taste wines for British Airways, for example (the closest thing I have to any commercial link), they have been submitted in response to a specific tender document. This means that the quality can vary from the sublime to the dire (I'm constantly amazed, and insulted, that some people clearly think we won't notice that a wine is technically faulty or over the hill). What we're looking for in this instance is something that is extremely sound and will appeal to as many people as possible at 33,000 feet – which generally means that the wine has to be a bit more obvious than wines we might enjoy on the ground, for our tasting equipment is far from its best in the strange atmosphere of a pressurised cabin. We also tend to discount wild and wacky wines which might appeal very much to a small proportion of fliers but many would find a turn-off (you can see the same, understandable policy at work in the choice of in-flight audio and films).

We go through up to 50 wines, always blind, sometimes having split the wines into two groups for two lots of tasters, to select the best candidates and then we all taste the finalists again to decide what to buy. This means that a scoring system inherited from fellow-consultant Colin Anderson, a Master of Wine whose nose was famously insured with Lloyds of London when he was in charge of wine buying for the precursor of Allied Domecq, works extremely well. We give faulty wines a gamma (or C grade), respectable wines a beta or B grade and standouts worth buying an alpha or A. In between these of course are all sorts of fine distinctions such as B+, A- – even B++?+, but we do tend to get there in the end. This apparently rather crude system allows a group of tasters to come to a consensus much faster than we would if we all assigned numerical scores and had to get out the calculator when we conferred.

In most of my tasting and writing I don't really need scores. What's important when I taste a range of mixed wines is to mark those I think good enough – which often translates into sufficiently good value (for most us price is important) – to recommend. A mere tick suffices. An exclamation mark draws my attention to something notable such as an absurdly hyberbolic claim on the back label or some strange new phenomenon. I'm sure, for instance, I gave an exclamation mark to the first Italian wine I saw labelled Shiraz, or to a curiously old vintage of a particularly commercial wine for example. 'GV' distinguishes the seriously good value bottles while real stinkers get a cross to bear.

I like the five-star system used by Michael Broadbent and Decanter magazine. Wines that taste wonderful now get five stars. Those that will be great may be given three stars with two in brackets for their potential. But Brits being as polite, or just plain cowardly, as we are, almost all the wines get between three and five stars in Decanter so it's not an especially nuanced scoring system – although I have been known to use it for wines likely to be very close together in quality such as de luxe champagnes or mature vintage ports.

When even I have to admit that I really need a numerical scoring system is when tasting a wide range of wines of the same sort when readers, or subscribers to, need a shorthand reference to my favourite wines. En primeur bordeaux, for example; early offerings from the latest burgundy vintage; almost any horizontal tasting from producers of varying competence.

I know that Americans are used to points out of 100 from their school system so that now they, and an increasing number of wine drinkers around the world, use points out of 100 to assess wines. Like many Brits, I find this system difficult to cope with, having no cultural reference for it.

So, I limp along with points and half-points out of 20, which means that the great majority of wines (though by no means all) are scored somewhere between 15 and 18.5, which admittedly gives me only eight possible scores for non-exceptional wines – an improvement on the five star system but not much of one. (I try when tasting young wines to give a likely period when the wine will be drinking best, so I do cover the aspect of its potential for development.)

But, perhaps strangely for someone who studied mathematics at Oxford, I'm not a great fan of the conjunction of numbers and wine. Once numbers are involved, it is all too easy to reduce wine to a financial commodity rather than keep its precious status as a uniquely stimulating source of sensual pleasure and conviviality.