Growing body of knowledge

By Fiona McDonald | 10th August 2023

“Our situation in South Africa is that we have a young fine wine culture with old geology,” said Dr Etienne Terblanche at Stellenbosch Wine Routes’ recent Terroir Tasting. “In Europe, it’s the opposite. They have a centuries old fine wine culture with relatively young geology.”

What’s the significance of that? Simply put, it’s that whereas the lines or easily applicable norms and rules of “this soil, that vine” work in Europe, the same criteria do not apply on the southern tip of Africa.

Terblanche is one of those rare creatures who can take complex scientific information, parse it and share it, making it comprehensible and easily digested by non-scientists. The approach to viticulture 20 years ago was totally different to what it is today, he said. Back in the late 90s and early 2000s the methodology was purely physical: to look at the soils, whether the aspect was north-, south-, east- or west-facing, the altitude and slope. “Nowadays it’s not so clean cut. We’ve realised that it doesn’t automatically follow that if you have ABC soil and slope, planting a particular grape variety will produce XYZ result,” he said.

There’s so much more to it – including the human and cultural element as well as an appreciation for variable climatic inputs. Terblanche then proceeded to synthesise the geology underlying the Western Cape’s soils, starting with the Pangea supercontinent 600-plus million years ago, explaining how and when the sedimentary soils and Malmesbury shales were derived, doing the same with the granite suite 200 million years ago and finally how the movement, intrusion, deposition and climatic weathering have contributed to the dirt beneath our feet.

“Now we sit with koffieklip soils in our valleys, weathered soils which are good for producing great wines – while soils mid-slope are vigorous,” he said. In Europe, the conventional wisdom is not to plant vineyard in the valleys because of the rich soils which have weathered from higher elevations. “They’re too vigorous – so the rule of thumb there is to plant higher up.”

In Stellies, it’s not like granite soils predominate in the north and shale in the south, for example. Europe is more cut and dried or distinctly delineated because their soils are geologically younger. “Here, mixed soils are everywhere!” And that’s where the viticulture becomes so crucial, considering rainfall, solar radiation and farming practices. An example he cited was the Polkadraai hills of Stellenbosch which felt the cooling effect of both Table and False Bay waters. “The area doesn’t quite get a full on fog such as that experienced in Sonoma, California, but there is a definite haze which results in decreased solar radiation but also increases humidity,” Terblanche said.

“This is an exciting time to be in research,” he said. “The challenge is to be able to take massive datasets available to us and to analyse and extrapolate results.”

All of that was a preamble to a tasting if four distinct flights of Stellenbosch wines: Chenin Blanc, Chardonnay, Pinotage and Cabernet Sauvignon to demonstrate the extensive work done by the Stellenbosch Wine Route and producers. The idea was to assess these wines, not to score or rate them, but to rather consider whether it was possible to distinguish differences in texture and mouthfeel which could be attributed to underlying geology.

Input from AdVini’s Dr Edo Heyns was that typicity sells. “This is something Burgundy has done so well. They have been able to convey the message about the diversity the region offers but also about its typicity; what makes Burgundy Burgundy.” People understand the difference between Chablis and Macon, for example, and can appreciate that while both are Burgundy, each is distinct.

This is the nub of the message Stellenbosch is driving. Nowhere was this more starkly obvious than the fourth flight of wines, the Cabernets. Oldenburg winemaker Nic van Aarde drew on his experience in vinifying Cabernet from the 2000s. “It used to be that we’d ripen the hell out of Cabernet to try and avoid those green characteristics South Africans were hammered for. So we’d burn off those pyrazines but then we’d sit with wines which were at 15% alcohol!”

Lessons learned in the interim have resulted in wines which are phenolically ripe, with finer tannins and little to no greenness. These included usage of cover crops, leaf plucking and opening and managing vine canopies better to balance vegetative and reproductive growth.

Dirk van Zyl, winemaker at Glenelly, was uniquely positioned to comment, having moved to the Simonsberg property after a few years at Saxenburg. “The biggest shift for me moving from the Polkadraai in the west to the Simonsberg in the north was the difference in soils. There was a coarser granite-derived soil at Saxenburg so I was never worried about picking Cabernet too early – but at Glenelly the decomposed granite soils are deeper.” His experience tasting the grapes during the 2023 vintage was “Glenelly has massive tannins – big, heavy and intense”. Not a problem when the property is owned by Bordelaise proprietors who are happy to take the long view, waiting years to release the wine and consciously making the wines to age for 10, 20 or more years!

“So I have to make very precise picking decisions at Glenelly,” he said, “in order to make the most of a much smaller window during which the sweet spot of tannin ripeness and optimum fruit ripeness is attained.”

As the Stellenbosch Wine Routes booklet detailing all the differences between wards in the north, south, east and west, each with differing geology, elevation, rainfall and climatic inputs, states: “Stellenbosch Cabernet renders unique and authentic expressions informed by its past, but profoundly reimagined in the present.”

Just as the proverbial single swallow does not make a summer, the achievement of Le Riche Reserve Cabernet Sauvignon 2020 as the Best in Show at the 2023 Decanter World Wine Awards does not mean that Stellenbosch Cabernet is the finished product. It does, however, reflect a growing appreciation for the fact South Africa – and Stellenbosch – is headed in the right direction, utilising its old geology to increase the appreciation for world-beating fine wines.

By Fiona McDonald