WineWisdom

Cool climate is important for its deep-seated implication for potential high quality and longevity in bottle. And New Zealand has adopted the cool climate mantle for the new world with some aplomb, but is its status as the new world model of cool climate all its cracked up to be?    

The country is over 1,000 miles long.  That’s longer that Italy, where growing conditions vary from cool, Alpine valleys in the north to scorched Sicilian shores in the south.  No-one would suggest that all of Italy is cool climate, though bits of it seem to fit. New Zealand tracks a similar trend from a significantly warmer Auckland to a significantly cooler Central Otago.

New world model of cool climate?

Degree days and MJTs (see box) are regarded as a sound starting point for climate and viticulture. But degree days are not always a reliable indicator in NZ, as Ivan Donaldson, of Pegasus Bay Winery in Canterbury pointed out: “Degree days here [Canterbury], in Marlborough, and in Martinborough are about the same, but we harvest later than Marlborough. Also the highest ever official temperatures in NZ were recorded here in Canterbury at 43°C.  We have regular days at 30° to 40°C. Auckland achieves 30°C once every 20 years. But Auckland is warmer on average than here.”  Degree days and MJTs are clearly only a part of the picture.

High diurnal temperature fluctuations during the ripening season are a common theme for new world wine regions. They’re not a particular feature of Mediterranean climates, nor of maritime temperate climates such as Bordeaux, and Jackson Estate’s winemaker, Mike Paterson, said the diurnal temperature fluctuation “that we experience in NZ is one of the things that makes NZ unique. During ripening we get 5-6°C nights and warm 31-32°C during the day. It’s the temperature difference that drives the metabolism and flavour profile of the fruit.”

Added to this, the sun is strong in New Zealand, so warm to hot days and long sunshine hours may be one thing, but the strength of the sun is another.  It is said that 20 minutes in the sun in New Zealand will burn you quicker than 20 minutes almost anywhere else in the world. Blair Walter, the winemaker at Felton Road said: “solar radiation is higher in Central Otago than in northern Europe. The earth is closer to the sun during the growing season and the ozone hole causes higher levels of UV radiation than in northern hemisphere.”

Whether these factors have any connection to the conundrum of new world ‘cool climate’ combined with high alcohol may be a mute point as alcohols have been rising here as much as any region across the world in recent decades.  However, winemakers argue high alcohols are a temporary thing whilst they get to grips with the NZ model.  “Alcohol is a dilemma” said Rudi Bauer, winemaker at Quartz Reef, “physiological and sugar ripeness don’t go hand in hand.  We need better vineyard management, and vine age. With more experience we will learn how to handle it.”

It is easy to forget how young a viticultural region is New Zealand.  Made even more youthful by the recent arrival of new and better-suited clonal material, discussed below.

Escarpment vineyard, Martinborough

 Moderating influences – site selection

It is known some of the best vineyard sites in the Médoc owe their proximity to the Gironde, where a bit of reflected warmth from the water late in the ripening season can be significant. And without the steeply inclined slopes of the Mosel which maximise insolation, riesling would struggle to ripen.

With New Zealand’s strong sun and warm days, moderating influences are more about site selection for cooling influences during the heat of the day, despite its baseline cool climate position.  Waiheke Island has a very warm climate, with small diurnal variation, and extreme heat has been known to give cooked flavours to wine.  Cooling breezes compensate in part, but the island has adapted its varietal mix to the warmth with syrah, cabernet sauvignon, merlot, chardonnay and viognier.  The island is hilly, so, said Matt Allen, the vineyard manager of Man O’War Vineyards, “we use south-facing slopes [away from the sun], which are sub-optimal for sun and light intensity for our whites, and the reds are on warmer, north-facing slopes.”  

Sitting at the bottom of North Island, Martinborough has no protection from the cold Southerlies, coming up from the Antarctic.   These cold southerlies influence Marlborough as well, and can whip through the Cook Straits towards Nelson.  Mike Trought, research leader at Marlborough Wine Research Centre said of Marlborough sauvignon blanc “the Awatere has smaller diurnals [than the Wairau], it’s cooler and can get southerly blasts which give tomato stalk and gooseberry characters, as well as vivacity.”

Rippon Vineyard is another case in point.  Owner Nick Mills said: “The thermal mass of Lake Wanaka is 13°C in winter and 15°C in summer. We have hot days, with average temperature of 30°C, but we get a cooling breeze from lake.  And the lake moderates our frost risk. We’ve had only 3 serious frosts in 25 years.” He added “Ruby Island [in the lake] blocks or rather ‘spoils’ the norwesterly winds a bit, it helps to dissipate the wind.  The island is a very important part of our mesoclimate.”

Regional identity

Developing amongst all of this is the emergence in New Zealand of real, identifiable, regional character, which includes an improving matching of grape varieties with site.  Clear trends are emerging such chardonnay, viognier, Bordeaux reds and syrah from the warmer North Island; pinot noir moving to slopes in Marlborough for better expression; and indeed different expressions of pinot noir depending on its regional origin. 

The greater humidity towards the north of NZ enables quicker ripening. In Hawkes Bay, said Tim Turvey of Clearview Estate, the climate is “cool, more temperate daytime temperatures with warm night time temperatures. We get sea breezes all day and the temperature doesn’t drop at night.” This suits ‘warmer’ grape varieties and Hawkes Bay has over 80% of NZ’s plantings of merlot and cabernet sauvignon, and, on a smaller scale, syrah.  And it is syrah that’s creating all the excitement as the later-ripening cabernet sauvignon declines slightly. At the 2007 Air New Zealand wine show, the Champion Wine of the Show Trophy went to syrah for the first time – Trinity Hill’s Homage Syrah 2006.

Aromatic varieties such as riesling, pinot gris, and gewürztraminer are beginning to make a name for themselves in Nelson, where, said Hermann Seifried, “the climate is temperate, with an ocean influence.  Hot for us in summer is 24°C to 25°C.” And this despite the region claiming to have the highest sunshine hours on average, in NZ. Seifried is impressed with the mouthfeel and extract achievable in Nelson and he plans to plant 1,000 grüner veltliner vines during 2008, one suspects harking a little to his Austrian heritage as well as the inherent quality of the grape variety.

There's more than vines

But it is pinot noir where most regional flavour differences are coming to light, in those regions where it’s found a natural home: Martinborough and Wairarapa, Marlborough, Canterbury/Waipara and Central Otago.

Part of this evolution is very recent, and comes alongside new clones, and changes in winemaking practice. Bill Spence, founder and general manager of Matua Valley Wines, said “for many years people tried to make cabernet sauvignon out of pinot noir.  It changed when Montana moved to Blenheim which was thought to be the place for sparkling wine -but sparkling wines clones were planted.  Then people tried to make pinot noir from bubbly-production clones. New clones arrived only 10-12 years ago resulting in a new wave of new wines.”

Pinot noir is the new, bright thing for Marlborough, but only since plantings have been moving off the flats. Neill Culley, the managing director and winemaker of Cable Bay in Waiheke Island, said “pinot noir in Marlborough took longer to establish because the plantings were in the wrong place –  on flat paddock next to sauvignon blanc.  The good sites are up in the hills.  Marlborough is now one of the top pinot noir producing sites in NZ.”

Regional differences are apparent, as Jeff Clarke, chief winemaker of Pernod Ricard, explained: “Flavour profile tends to reflect the mesoclimate – Marlborough has lightest, red berry fruit, tending to strawberry, more aromatic, fruit characters, with soft tannins.  Martinborough/Wairarapa shows fulsome plummy fruit with a round and robust structure.”  In Waipara, he said the characters are more earthy, dense, brambly and Central Otago is pure, linear with dark cherry, wild thyme and attractive herbal characters.

But the best is yet to come, as vines age.  Most pinot noir vines, especially the new clones have been planted only in the last ten years. Winemaker at Mt. Difficulty, Matt Dicey said: “”Mt Difficulty has some of the oldest vineyards [in Central Otago], from 1992 to 1994. [We developed the label] Roaring Meg as somewhere to put the young fruit. There is a clear cut between depth and concentration for Mt Difficulty – from year 10 we start getting concentration and complexity.”

Pragmatism in the marketplace

Built into growing regional identities in New Zealand is the need for producers to draw on fruit from those distinct regions in order to offer the market key styles well regarded on the international stage. Producers outside Marlborough, such as Matua Valley and Cable Bay, must offer a Marlborough sauvignon blanc in their range, even if it means buying in expensive fruit, or having operations in Marlborough. Hawkes Bay sauvignon blanc may be a more economical item, with its more rounded and softer palate than Marlborough, but it simply doesn’t cut the mustard with customers who are looking for that benchmark zingy identity conferred by the Marlborough region.  Central Otago pinot noir is becoming another ‘must range’ for producers.

Uniquely NZ

Regardless of cool or cooler, marginal climates and clear differences along the 1000 mile north-south stretch that is NZ, Bauer strikes a chord for New Zealand, saying “our strongest card is our fruit – its clarity and the expression of that clarity. It doesn’t matter which grape variety. It is the core of our country. Germany has acid/residual sugar balance, Italy has tannin/acid balance. We need to learn how to harness our fruit so it’s stylish and extraordinary.”

Mean January or July temperature, depending on hemisphere

Degree days. Mean monthly temperature less 10 (degrees) multiplied by days in month, and totalled for seven month growing season.

Sources:
Viticulture and Environment. John Gladstones
National Institute of Atmospheric Research (NIWA)
Wine Atlas of the World, sixth edition. eds. Hugh Johnson, Jancis Robinson
NB: values from different sources may not be directly comparable.