It would be lovely to think that cost and quality were inextricably tied together. The world would be a much simpler place - you'd only need to know a simple rule - the more it costs, the better it is. We want to believe this, even though in our hearts we know it ain't necessarily so. Clothes with a designer label must be better than clothes bought in a department store, they must be, or why else would they cost so much? With wine the argument is similar - Chateau Lafite costs what it does because it's a better wine than the rank and file. True. But is it 100 times better?

Enough theory and on to a little practical application. This week's wine tasting at the Radisson (see above) gave us a chance to taste some excellent wines in combination with good food. We tasted a truly magnificent Lafite '83, an expensive wine that tasted expensive. But the really interesting wines for me that night were the two other reds, Los Vascos Grande Reserva 2001 and Quinta do Carmo Reserva 2001, both from the Rothschild international stable. The first, from Chile, surprised me at once. The more you taste wine, the more you rely on your nose to tell you what to expect before you drink the wine. I smelt the wine, and somewhere in my mental database I found a match: I expected a sharp, tannic bite. Oddly none came, and the more the wine remained open, the more polished it became. And the more I let it swirl around my palate, the more cinvinced I was that this was a wine in the €25-€30 bracket.

Next we tasted the Portuguese Quinta do Carmo, a much more classically styled wine, closer to the Bordeaux mold. The wine writers around me were in agreement - a better wine than the first. I wasn't so sure, and I'm still not. Still less sure when the prices were discovered, the first will normally retail at around €16, the second around €35. It was the same old question; was the second wine more than twice as good as the first?

And that's when John Wilson gave me a really useful tip. If you score a wine out of 100 and then divide that number by its price, you get a measure of quality set against cost. Let's say you score the first wine 90/100 and the second 96/100. If quality and cost really were linked together, then you when you do this calculation you should always end up with much the same number. But when you do the maths with these figures, the first wine costs you 18 cents per quality point and the second costs you 36 cents. By that measurement you're doing twice as well when you buy the first wine, even if it has a lower score than the second.

Wine of the Week

Los Vascos Grande Reserva 2001

An very elegant wine that delivers a taste that's normally associated with wines costing a great deal more. Treat it with respect, chambre it and maybe even decant it, and it will repay you with a very classy glass of wine, and at the special offer price it's quite remarkable value.

Available O'Brien's Off Licenses, on special offer at €12.50