Given the remarkable advances in South African wine in the past 15 years, it's easy to assume that before then all was dross. Much was indeed drear at least - but the danger was always that the finest part of Cape winemaking tradition would also be chucked out with the turn to the challenges of pleasing new international markets after 1994.

Now that a realistic self-confidence is justifiably returning to local winemakers (different from earlier strident claims made on the basis of ignorance), the possibility of Cape wine's older greatness is also becoming clearer to those who get to taste a few wines of the decades before the 1980s. It was during the 1980s when, for various reasons (too much irrigation, worsening virus, ignorant and over-zealous oaking all contribute) problems set in, although a few good wines were still made.

It's important now to recognise this great tradition - partly to invoke the encouragement of knowing that greatness is possible here, partly to build on local achievements rather than trying to compete with bland internationalism that has no roots other than immediate market forces. Even if the knowledge is only in the air (actually sampling such wines is a rare privilege), young winemakers must know their place in a tradition with a history as well as, let's hope, a future.

For three years, chair and part-owner of the Trophy Wine Show, Michael Fridjhon, has organised a remarkable tasting on the day before the judges, local and foreign, start their work. Through useful contacts, and friends and colleagues with interesting cellars, he assembles a few dozen wines: reds more than 25 years old, whites more than 15.

Some are legendary (like Nederburg Auction Cabernet Sauvignon 1974, GS Cabernet 1966 and 1968, Chateau Libertas 1940), but many are decidely not (a majestic, concentrated Swartland Co-op Pinotage 1971 was a 2010 triumph). Some wines, from both categories, are valiantly tired, some are quite frankly dead, others gloriously triumph over time.

The experience of tasting them never fails to impress and exhilarate everyone lucky enough to attend alongside the primary intended tasters - the foreign judges with little idea of the historical background to the wines they have come to assess.

This year the star whites performers included a brilliant bottle of the famous Klein Constantia Sauvignon 1986, and two chardonnays: Backsberg 1985 and Overgaauw 1986 - not great wines, definitely past their best but surprisingly drinkable and interesting still. Amongst the reds (the majority of the wines), my heroes were Alto Rouge 1974, Rustenberg Cabernet Sauvignon 1971, GS Cabernet 1966, KWV Pinotage 1974 and the oldest, a half-bottle of Zonnebloem Cabernet 1959.

It is notable how well old pinotages often perform. The KWV was much admired by Neal Martin, a Brit who's recently become the official taster of South African wines for Robert Parker's Wine Advocate - an immensely important publication for the American market particularly. He Tweeted his appreciation around the world! [In the photo, Neal is helpfully wielding a corkscrew before the tasting - and doing so skillfully, as opening these old bottles with their often crumbly corks is not always straightforward.]

Of the 1959 Zonnebloem, still full, rich and lingering after 62 years, Neal remarked: "If you put that in a line-up of 1959s from Bordeaux it would have knocked most of them out of the field." He said later how the tasting had surprised him, and given him an entirely new perspective on Cape wine.

There are locals, too, who should learn that South African wines are not precluded from attaining grand maturity.

First published in the Mail & Guardian, 3-9 June 2011