Last time I brought up the subject of South African wine, I promised to follow up with the results of the Old Mutual Trophy Wine Show I was involved in in May and an update of the source of the problem flavours found in some Cape reds. After a series of reports of rubbery and singed characters identified in certain South African wines as possibly, but not conclusively, affected by vineyard virus, Wines of South Africa, the body responsible for Cape wines, decided that it was time for action; they isolated some of the offending examples and sent them off for analysis along with a list of "clean wines". A team at the University of Stellenbosch is assessing the evidence. They're not saying how long it will be before they can tell us the results, or if, indeed, they will.

That doesn't mean you should avoid South African wine. As the Trophy Wine Show and other tastings this summer confirm, there's plenty to be enjoyed. The offending characters are mostly confined to certain reds, and even then only in a minority. White wines appear to be immune to the problem, which is just as well because following a big swing towards planting red varieties in the late 1990s and early 2000s, white grape varieties are on the way back and now occupy 56 per cent of South Africa's vineyard area. Chenin blanc is South Africa's most widely planted grape variety, followed by colombard, chardonnay and sauvignon blanc. A good-value example of the former is the distinctly Loire-like, gooseberryish 2007 Cederburg Sustainable Chenin Blanc, £7.50, Waitrose. Less surprisingly, cabernet sauvignon leads the roll-call of reds followed by the fast-climbing shiraz, then merlot and, of course, pinotage.

The show highlighted the importance of the country's white grape varieties, in particular sauvignon, chardonnay and semillon. Best white trophy went to 2007 Zonnebloem Limited Edition Semillon and while we wait for some of the winners to make their appearance in the UK, the best example of Cape semillon I've come across here is the 2006 Vergelegen Prestige White, £21.50, Waitrose Wine Direct and top branches, an intense, richly concentrated, dry, semillon-based white whose lime-zesty fruit characters come close to top Graves in style. Trophy for best chardonnay went to the 2006 Jordan Nine Yards Chardonnay, £18-£19.85, George Hill, Loughborough (01509 212717), Swig, London (08000 272272), Frank Stainton Wines, Kendal (01539 731886). For excellent Cape chardonnay at a less elevated price, try Jordan's elegant 2006 Stellenbosch Barrel-Fermented Chardonnay, around £11.35, George Hill, Frank Stainton, or the rich, butterscotchy 2006 Neil Ellis Chardonnay, £9.19, Tesco.

One of the surprises was the performance of Nederburg, an old Cape warhorse back on track with the most successful producer award thanks to the talents of its cellarmaster, Razvan Macici. Nederburg won a trophy for best unwooded sauvignon blanc with its pristine 2007 Nederburg Private Bin D234 Sauvignon Blanc, while Quoin Rock's fine 2007 The Nicobar won the wooded sauvignon trophy. South African sauvignon is starting to rival New Zealand for quality, albeit in a more restrained expression. See it for yourself in the superb, sancerre-like 2007 Iona Elgin Sauvignon Blanc, £9.99, Waitrose, the consistently fine, aromatic 2007 Vergelegen Sauvignon Blanc, £8.79, Waitrose, or the green peppery 2007 Darracott Sauvignon Blanc, £8.99, M&S and the 2007 Paul Cluver Sauvignon Blanc, Elgin, £9.75, Jeroboams, whose nettley aromas and tropical fruit make an ideal summer's day dry white. BTW: the excellent site, sawines.com, will do its utmost to find you a Cape wine you can't otherwise get hold of.