Down by the seaside

My little suburban pad in Cape Town is a lesson in viticulture. The north-facing lounge is a veritable oven when the sun comes out and if I don't take care, the bonsai are reduced to cinders.

The study looks south to Muizenburg and False Bay. It never gets direct sunlight and the breeze that hits the window comes straight from the heart of the Antarctic. Even on warm days the chill is numbing.

The distance between the two rooms is only four metres.

Exactly the same nuances of physics apply to the hills of Darling area, up the west coast of the Cape. South-facing slopes are cool and maritime as they overlook the cold Atlantic Ocean but just a few hundred metres away, the north-facing slopes of the same hills will experience almost semi desert conditions.

'Darling isn't the alpha and omega of wine producing areas simply because you have such extremes,' says Distell viticulturist and Stellenbosch University lecturer Professor Eben Archer.

The lesson goes to the entire industry, says the Professor: site selection is absolutely critical when planting vineyards.

Here the soils are excellent but the low rainfall makes water management crucial.

Not many kilometres down the coastline are the Durbanville hills - overlooking the Cape peninsula, many of these vineyards experience the influence of both the Atlantic and the warmer Indian Ocean, whose currents occasion their way around the Cape.

Rainfall is higher here and the area's proximity is farther from the semi desert (only two to three hours drive up the coast from here) so both north and south facing slopes are relatively moderate and a little more hospitable to aspiring grape farmers.

Elgin is buffered from the ocean by the fold mountains but gets the wind sneaking over the peaks from Kleinmond (just on the Cape Town side of the coastal village, Hermanus) which helps to moderate this mild climate.

It's a distinctly high-lying valley, up to about 1000m above sea.

Here, like Darling's south-facing slopes and most of Durbanville's, the vineyards are protected from the dramatic spikes in summertime temperatures experienced further from the coast.

Grape growing wants moderation, says Archer, because ideally the vine should grow at the same rate at which it ripens fruit (rather than leaf growth exceeding ripening because all the energy goes to the wrong part of the plant).

Further south-east, the Agulhas Plain is the hottest cool property right now. The name refers to a distinct eco-region of gently rolling hills in the cusp of an amphitheatre of bergs which run from the Franskraal mountains near Stanford, across to Bredasdorp and down to Struisbaai.

An almost perpetual south-easterly wind, straight from the ocean, keeps this area so moderate and cool that it's ideal for grapes. The only problem is that the soils tend to be a bit brackish because of the high salt content and vineyards have to be planted accordingly.

Climate change modelling by the University of Cape Town shows that a pattern of warming and drying will take place, where climate envelopes are expected to shift to the south and east. This means that the semi-desert conditions up the west coast might infringe upon existing vineyards.

Darling may well become even drier than it already is and more dependent on sea breezes to keep fruit cool during summer. Inland areas, especially those warmer parts which are on the margins of tolerable warmth, might well become unviable grape areas.

Suddenly the Agulhas Plain, the most moderate area buffered from the harsh northern conditions by the Cape Fold Mountains, becomes critically strategic for the future of quality wine production. But there's the natural vegetation to contend with: national legislation is tightening up the protection of this unique flora. It may well be more viable to use the land for wild flower harvesting than ploughing it up for vines, an activity which is illegal now without the necessary permit.