New Zealand Wine - Climate and Soil

Climate and Soil

Wine regions are mostly located in free draining alluvial valleys (Hawke's Bay, Martinborough, Nelson, the Wairau and Awatere valleys of Marlborough, and Canterbury) with notable exceptions (Waiheke Island, Kawarau Gorge in Central Otago). The alluvial deposits are typically the local sandstone called greywacke, which makes up much of the mountainous spine of New Zealand.

Sometimes the alluvial nature of the soil is important, as in Hawke's Bay where the deposits known as the Gimblett Gravels represent such quality characteristics that they are often mentioned on the wine label. The Gimblett Gravels is an area of former river bed with very stoney soils. The effect of the stones is to lower fertility, lower the water table, and act as a heat store that tempers the cool sea breezes that Hawke's Bay experiences. This creates a significantly warmer meso-climate.

Another soil type is represented in Waipara, Canterbury. Here there are the Omihi Hills which are part of the Torlesse group of limestone deposits. Viticulturalists have planted Pinot noir here due to French experience of the affinity between the grape type and the chalky soil on the Côte-d'Or. Even the greywacke alluvial soils in the Waipara valley floor has a higher calcium carbonate concentration as can be witnessed from the milky water that flows in the Waipara River.

The Kawarau valley has a thin and patchy top soil over a bed rock is schist. Early vineyards blasted holes into the bare rock of north facing slopes with miners caps to provide planting holes for the vines. These conditions necessitate irrigation and make the vines work hard for nutrients. This, low cropping techniques and the thermal effect of the rock produces great intensity for the grapes and subsequent wine.

The wine regions in New Zealand stretch from latitudes 36°S in the north (Northland) (comparable in latitude to Jerez, Spain), to 45°S (Central Otago) in the south (comparable in latitude to Bordeaux, France). The climate in New Zealand is maritime, meaning that the sea moderates the weather producing cooler summers and milder winters than would be expected at similar latitudes in Europe and North America. Maritime climates tend also to demonstrate higher variability with cold snaps possible at any time of the year and warm periods even in the depth of winter. The climate is typically wetter, but wine regions have developed in rain shadows and in the east, on the opposite coast from the prevailing moisture-laden wind. The wine regions of New Zealand tend to experience cool nights even in the hottest of summers. The effect of consistently cool nights is to produce fruit which is nearly always high in acidity.