New Zealand wine is largely produced in ten major wine growing regions spanning latitudes 36° to 45° South and extending 1,600 kilometres (990 mi). They are, from north to south
Northland, Auckland, Waikato/Bay of Plenty, Gisborne, Hawke’s Bay, Wellington, Nelson, Marlborough, Cantebury/Waipara, and Central Otago. Wine regions are mostly located in free draining alluvial valleys (Hawke’s Bay, Martinborough, Nelson, the Wairau and Awatere valleys of Marlborough, and Cantebury) 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.
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.
Characteristic of NZ winemaking methods is the universal use of stainless steel in winemaking, adapted from the norms and standards of the New Zealand dairy industry. There was an existing small-scale industrial infrastructure ready for winemakers to economically employ. This pervasive use of stainless steel almost certainly had a distinctive effect on both New Zealand wine styles and the domestic palate. The early wines which made a stir internationally were lauded for the intensity and purity of the fruit in the wine. Indeed, the strength of flavor in the wine favored very dry styles despite intense acidity. While stainless steel did not produce the intensity of fruit, it allowed for its exploitation. Even today, New Zealand white wines tend toward the drier end of the spectrum.
New Zealand red wines are typically made from a blend of varietals, Cabernet Sauvignon, Merlot, and much less often Cabernet Franc, Petit Verdot, and Malbec, or Pinot Noir. Recently, in Hawkes Bay, there have been wines made from Syrah, either solely or blends, as well as Tempranillo, Montepulciano, and Sangiovese.
In white wines Chardonnay and Sauvignon Blanc predominate in plantings and production. Typically Chardonnay planting predominate more the further north one goes, however it is planted and produced in Central Otago. There is no discernible difference in styles for Chardonnay between the New Zealand wine regions so far. Individual wine makers and the particular qualities of a vintage are more likely to determine factors such as malolactic fermentation or the use of oak for aging.
New Zealand Sauvignon Blanc has been described by some as "alive with flavors of cut grass and fresh fruits", and others as "cat's pee on a gooseberry bush" (but not necessarily as a criticism). Other white varietals commonly include (in no particular order)Riesling, Gewurztraminer, and Pinot Gris, and less commonly Chenin Blanc, Pinot Blanc, Muller-Thurgau, and viognier. (source: Wikipedia)
An interesting look at a highly mechanized winery in the Marlborough Appellation of New Zealand, courtesy of ViscosityTV (episodes 1-4).