Head for the hills
“Hills are for grapevines, the valleys are for sheep” commented an Italian winemaker as he negotiated his four-wheel-drive vehicle through steeply-sloping vineyards.
An increasing number of New Zealand vineyards are being planted on hillsides despite the extra cost of tending and harvesting hillside vines. Waipara-based Greystone Wines winemaker, Dom Maxwell, estimates that their hillside grapes cost 30-40% more than those grown on more easily manageable fruit from the flats.
The sheltered valley floor can be a heat trap while the more exposed hillside vineyards can be cooler despite having higher sunshine hours.
“You can really see the quality of hillside grapes which tend to be smaller and more concentrated with a higher tannin potential,” says Maxwell.
Over the centuries soil gets washed from the hillsides and onto the valley floor where deeper, richer soils can compromise wine quality. While the soils on the flats tend to be deeper, richer and more consistent, those on the hills have better access to minerals and often better drainage.
I recall being told that every rise in 10 degrees of elevation gave an extra 1°C of heat summation. It is not quite as simple as that, according to Maxwell. The sheltered valley floor can be a heat trap while the more exposed hillside vineyards can be cooler despite having higher sunshine hours. A longer ripening period is good for quality.
Windy hillside vineyards tend to suffer less disease pressure than the more humid valley floors while the more effective hillside drainage means fewer problems if a downpour strikes during the ripening period.
Hillside vineyards tend to be less frost-prone than valley floor vineyards, which gave them a massive advantage when frost struck in the 2021 ripening season and the valley vineyards suffered heavy losses.